Patent Publication Number: US-2021179461-A1

Title: Ozone distribution in a faucet

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of U.S. patent application Ser. No. 15/850,956, filed Dec. 21, 2017, which is a divisional application of U.S. patent application Ser. No. 14/362,764, filed Jun. 4, 2014, now U.S. Pat. No. 9,919,939, which is a 371 national phase filing of International Application No. PCT/US2012/068283, filed Dec. 6, 2012, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/567,392, filed Dec. 6, 2011, the disclosures of which are expressly incorporated by reference herein. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates generally to an electronic faucet and, more particularly, to an electronic faucet including a water treatment device. 
     Fluid delivery devices, such as faucets, may include a fluid treatment device. For example, a treatment device may include a filter or a water softener configured to treat the water before it flows from the faucet. A user input may be provided for controlled use of the fluid treatment device. 
     Additionally, a faucet may be configured to provide water from an outlet with different flow patterns or modes (e.g., stream, spray, or other aerated flow). A user may toggle between the flow modes using mechanical and/or electrical inputs. 
     According to an illustrative embodiment of the present disclosure, a faucet comprises a spout, a first valve in fluid communication with the spout, and a second valve spaced apart from the first valve and in fluid communication with the spout. The faucet further comprises a first flow path fluidly coupled to the first valve, a second flow path fluidly coupled to the second valve, and an antibacterial device fluidly coupled to the second flow path. The faucet is configured to selectively flow fluid through one of the first flow path and the second flow path. When in the first flow path, the fluid flows through the first valve in spaced relation to the antibacterial device. When in the second flow path, the fluid flows through the second valve and the antibacterial device. 
     According to another illustrative embodiment of the present disclosure, a faucet for dispensing a fluid comprises a spout and a pull-out spray head removably coupled to the spout and including an outlet. The faucet further comprises a valve assembly in fluid communication with the outlet and an antibacterial device configured to output a treatment into the fluid. 
     According to yet another illustrative embodiment of the present disclosure, a fluid delivery device for outputting a fluid comprises a spout supporting an outlet and a valve assembly in fluid communication with the outlet. The fluid delivery device further comprises a controller operably coupled to the valve assembly and a fluid treatment assembly operably coupled to the controller. The controller is configured to detect operation of the fluid treatment assembly based upon a temperature and a flow rate of the fluid. The controller also is configured to control operation of the fluid delivery device when the flow rate is lower than a predetermined minimum flow rate and when the temperature is greater than a predetermined temperature. 
     According to another illustrative embodiment of the present disclosure, a faucet comprises a spout supporting an outlet and a valve assembly in fluid communication with the outlet. The faucet further comprises a water treatment assembly having a water treatment device and a housing. A first portion of water is configured to flow through the water treatment device and a second portion of water is configured to flow around the water treatment device. The first and second portions of water are generally coaxial in the housing. The water treatment device is configured to output a treatment to the first portion of water. 
     According to another illustrative embodiment of the present disclosure, a housing for a fluid treatment device of a faucet comprises an inlet tube, a first cavity fluidly coupled to the inlet tube, a second cavity fluidly coupled to the first cavity and supporting the fluid treatment device, and an electrically operable valve supported within the first cavity. A fluid treatment assembly is supported within the second cavity and is fluidly coupled to the electrically operable valve. An outlet tube is fluidly coupled to the second cavity. The first cavity is substantially aligned with the second cavity. The fluid in the first cavity flows through the electrically operable valve and is directed into the second cavity. 
     According to a further illustrative embodiment of the present disclosure, a faucet for delivering fluid comprises a spout, an electrically operable valve fluidly coupled to the spout, and an ozone treatment device configured to provide ozone in the fluid. The faucet further comprises a capacitive sensor operably coupled to the ozone treatment device. The capacitive sensor provides an output signal. The faucet also comprises a controller operably coupled to the capacitive sensor. The controller is configured to monitor the output signal from the capacitive sensor to selectively operate the ozone treatment device. 
     According to a further illustrative embodiment of the present disclosure, a faucet comprises a spout, a first valve assembly in fluid communication with the spout, and a second valve assembly in fluid communication with the spout and the first valve assembly. The faucet further comprises a third valve assembly in fluid communication with the spout, a fluid treatment assembly in fluid communication with the third valve assembly, and a user input. The user input is configured to selectively flow fluid through the first and second valve assemblies when in a non-treatment mode, and is configured to selectively flow fluid through the third valve assembly and the fluid treatment assembly when in a treatment mode. 
     According to another illustrative embodiment of the present disclosure, an electronic fluid delivery device comprises a spout configured to deliver fluid from an outlet, a valve assembly in fluid communication with the spout, and a sensor operably coupled to the spout and configured to detect a flow mode at the outlet. The electronic fluid delivery device further comprises a user input operably coupled to the sensor and a controller in electronic communication with the sensor and the user input. The sensor is configured to provide an electrical signal to the controller indicative of the detected flow mode at the outlet. 
     Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed description of the drawings particularly refers to the accompanying Figures in which: 
         FIG. 1  is a perspective view of an illustrative embodiment faucet of the present disclosure; 
         FIG. 2A  is an exploded perspective view of a water treatment assembly of the faucet of  FIG. 1 ; 
         FIG. 2B  is a further exploded perspective view of the water treatment assembly of the faucet of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of a water treatment housing of the water treatment assembly of  FIG. 2 , taken along line  3 - 3  of  FIG. 1 ; 
         FIG. 4A  is a detailed view of the water treatment housing of  FIG. 3  when the faucet is operating; 
         FIG. 4B  is a detailed view of the water treatment housing when the faucet is not operating; 
         FIG. 5  is a cross-sectional view of the water treatment assembly of  FIG. 2 , taken along line  5 - 5  of  FIG. 1 ; 
         FIG. 6  is a perspective view of the water treatment housing of  FIG. 4A ; 
         FIG. 7  is a diagrammatic view of the present disclosure, illustrating a plurality of inputs and at least one output; 
         FIG. 8  is a perspective view of an alternative embodiment faucet of the present disclosure; 
         FIG. 9  is an exploded perspective view of an alternative water treatment assembly of the faucet of  FIG. 8 ; 
         FIG. 10  is a perspective view of the water treatment assembly of  FIG. 9 ; 
         FIG. 11  is an exploded perspective view of the water treatment assembly of  FIG. 10   
         FIG. 12  is a cross-sectional view of the water treatment assembly of  FIG. 10 , illustrating the flow of water when the faucet is in a non-treatment mode; 
         FIG. 13  is a cross-sectional view of the water treatment assembly of  FIG. 10 , illustrating the flow of water when the faucet is in a treatment mode; 
         FIG. 14  is an exploded view of a water treatment device and a cap; 
         FIG. 15  is a cross-sectional view of the water treatment device of  FIG. 14 , taken along line  15 - 15  of  FIG. 11 ; 
         FIG. 16  is a cross-sectional view of the water treatment device and the cap of  FIG. 14 , taken along line  16 - 16  of  FIG. 11 ; 
         FIG. 17A  is a schematic view of the illustrative water treatment assembly of  FIG. 10 ; 
         FIG. 17B  is a schematic view of an alternative embodiment of the water treatment assembly of  FIG. 17A ; 
         FIG. 18A  is a first portion of a diagrammatic view of an illustrative method of operation according to the present disclosure, illustrating a plurality of inputs and conditions; and 
         FIG. 18B  is a second portion of the diagrammatic view of  FIG. 18A . 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     The embodiments of the invention described herein are not intended to be exhaustive or to limit the invention to precise forms disclosed. Rather, the embodiments selected for description have been chosen to enable one skilled in the art to practice the invention. Although the disclosure is described in connection with water, it should be understood that additional types of fluids may be used. 
     Referring to  FIGS. 1 and 2 , an illustrative embodiment faucet  10  is shown including a spout body  12 , a hub  14 , a spray head  15 , a valve assembly  20 , a waterway assembly  24 , a mounting assembly  35 , a water treatment assembly  50 , and a controller  136  ( FIG. 7 ). In operation, faucet  10  receives water from hot and cold water supplies  6  and  8 , respectively, and selectively mixes the incoming water to provide water to an outlet  2  at spray head  15 . Faucet  10  may be mounted to a sink deck  5  or other suitable surface with outlet  2  positioned to direct water into a sink basin  1 , for example. 
     The illustrative hub  14  of faucet  10  is a generally hollow component having a vertically disposed body portion  14   a  and an angled valve portion  14   b  extending therefrom. As shown in  FIG. 1 , open ends  16 ,  18  of body portion  14   a  are longitudinally disposed and open end  22  of valve portion  14   b  is laterally disposed at an angle from open ends  16 ,  18 . In particular, valve portion  14   b  is illustratively positioned at any angle greater than 00 and less than or equal to 90° relative to body portion  14   a.  Body portion  14   a  of hub  14  includes an open bottom end  16  that is configured to be supported above sink deck  5 . Body portion  14   a  of hub  14  also includes an open top end  18  that is configured to mate with spout body  12 . For example, top end  18  of body portion  14   a  may include an internally threaded bore (not shown) that is sized to receive and engage an externally threaded end (not shown) of spout body  12 , thereby securing spout body  12  onto hub  14 . 
     Referring to  FIG. 1 , similar to body portion  14   a  of hub  14 , valve portion  14   b  also includes an open end  22  for coupling with a handle  34  of valve assembly  20 . The illustrative valve assembly  20  of faucet  10  includes handle  34  and at least a valve body  32 . Valve assembly  20  is supported by valve portion  14   b  of hub  14  and may be removably coupled thereto. In this illustrative embodiment, valve assembly  20  may be removed from the open end  22  of valve portion  14   b  for cleaning or servicing. Valve body  32  may be a conventional mixing valve that uniformly mixes the hot and cold water entering valve assembly  20  from inlet tubes  26 ,  28 , respectively. For example, valve body  32  may be a movable disc variety or a ball-type variety. Furthermore, valve assembly  20  and mixing valve  32  may be of the type described in U.S. Pat. No. 7,753,074 to Rosko et al., issued on Jul. 13, 2010, which is expressly incorporated by reference herein. 
     Hub  14  of faucet  10  may be formed of a traditional metallic material, such as zinc or brass. It is also within the scope of the present disclosure that hub  14  may be formed of a non-metallic material, such as a polymer. Suitable non-metallic materials that may be used to construct hub  14  include cross-linkable polyethylene (PEX), polybutylene terephthalate (PBT), polyester, melamine, melamine urea, and melamine phenolic. 
     As shown in  FIG. 1 , hub  14  is coupled to mounting assembly  35  above sink deck  5 . Mounting assembly  35  includes at least a pedestal  36 , which is coupled to hub  14  above sink deck  5 , and a base plate  38 . Pedestal  36  is positioned intermediate bottom end  16  of hub  14  and base plate  38 . Conventional sealing members, such as o-rings (not shown), may be positioned between pedestal  36  and hub  14 , and similarly, between pedestal  36  and base plate  38 . Base plate  38  is supported above sink deck  5  and a conventional sealing member (not shown) may be positioned between base plate  38  and sink deck  5 . Conventional fasteners (such as threaded shanks and nuts) may be used to stabilize hub  14  and couple base plate  38  to sink deck  5 . 
     With continued reference to  FIG. 1 , illustrative waterway assembly  24  of faucet  10  includes a hot water inlet tube  26 , a cold water inlet tube  28 , and an outlet tube  30 . Hot and cold water inlet tubes  26 ,  28  of waterway assembly  24  may be fluidly coupled to hot and cold water supplies  6 ,  8 , respectively, for receiving water into faucet  10 . Illustratively, outlet tube  30  includes a first portion  30   a  and a second portion  30   b.  Both first and second portions  30   a,    30   b  of outlet tube  30  are fluidly coupled to water treatment assembly  50 . More particularly, first portion  30   a  extends between valve assembly  20  and a water treatment housing  54  of water treatment assembly  50 . Second portion  30   b  extends below water treatment housing  54  and bends upwardly to pass through spout body  12  and couple with spray head  15  to deliver water from outlet  2 . 
     As shown in  FIG. 1 , inlet tubes  26 ,  28  extend beneath hub  14  and may include conventional fluid couplings, such as nuts, for fluidly coupling hot and cold inlet tubes  26 ,  28  onto hot and cold water supplies  6 ,  8 , respectively. Likewise, first portion  30   a  of outlet tube  30  may include conventional fluid couplings for fluidly coupling to water treatment housing  54  and valve assembly  20 . Additionally, second portion  30   b  may include conventional fluid couplings for coupling to water treatment housing  54 . Furthermore, conventional sealants (e.g., o-rings) may be included with the conventional fluid couplings. For example, waterway assembly may be constructed by the method set forth in International Patent Application No. PCT/US10/25524 to Nelson et al., filed Feb. 26, 2010, the disclosure of which is expressly incorporated by reference herein. 
     To limit contact between the water in faucet  10  and metallic components, waterway assembly  24  may be formed of a flexible, non-metallic material, such as a polymer, illustratively a cross-linkable polymer. Alternatively, waterway assembly  24  may be lined with a non-metallic material. As such, waterway assembly  24  is illustratively electrically non-conductive. In one illustrative embodiment, substantially the entire waterway assembly  24 , including inlet tubes  26 ,  28 , and outlet tube  30  is formed of a polyethylene which is subsequently cross-linked to form cross-linked polyethylene (PEX). Other suitable materials that may be used to construct waterway assembly  24  include polyethylene (PE) (such as raised temperature resistant polyethylene (PE-RT)), polypropylene (PP) (such as polypropylene random (PPR)), and polybutylene (PB). It is further envisioned that waterway assembly  24  may be constructed of cross-linked polyvinyl chloride (PVCX) using siline free radical initiators, cross-linked polyurethane, or cross-linked propylene (XLPP) using peroxide or siline free radical initiators. It is within the scope of the present disclosure that the polymer material used to construct waterway assembly  24  may include reinforcing members, such as glass fibers. 
     As shown in  FIG. 1 , spray head  15  is removably coupled to spout body  12  and is in fluid communication with second portion  30   b  of outlet tube  30 . Illustrative spray head  15  is a pull-down type but it is appreciated that spray head  15  may embody other types of spray heads. Spray head  15  is operably coupled to spout body  12  through a coupling (not shown), for example resilient fingers, bayonet coupling, or magnetic coupling. In operation, spray head  15  may be configured in a first position or a second position. More particularly, in the first position, an end  13  of spray head  15  is proximately coupled to an end  11  of spout body  12 . Conversely, in the second position, spray head  15  extends from spout body  12  via second portion  30   b  of outlet tube  30  such that end  11  of spout body  12  and end  13  of spray head  15  are spaced apart. Although the disclosure is described in connection with a pull-out spray head, it should be understood that additional types of spray heads or spout bodies may be used. For example, faucet  10  may include a spout having an outlet with a fixed aerator thereto. 
     Referring to  FIGS. 1 and 7 , spray head  15  may be configured to adjust the flow mode of the water at outlet  2 . The flow mode of operation may be a spray, a stream, or an aerated mode, or any combination thereof, and may include additional flow outlet patterns. Spray head  15  or hub  14  may be mechanically or electrically coupled to a mode sensor  120  in order to communicate the flow mode to controller  136 . More particularly, mode sensor  120  may be positioned on or within faucet  10  and may include a user input (not shown) to electrically toggle or switch between a stream mode, a spray mode, or other aerated modes, for example. A stream mode may output water from outlet  2  in a laminar, less turbulent manner than a spray mode. Mode sensor  120  may be configured to detect changes in specific characteristics of the water or the flow pattern, for example the turbulence of the water, in order to determine the mode. 
     Mode sensor  120  may be a piezoelectric element, a radio frequency (“RF”) device, a mechanical latching switch, a wireless sensor, a turbine generator for detecting flow rate, a deflection switch, a magnetic or Hall-Effect sensor, or a capacitive sensor, for example, in electronic communication with the user input in order to vary the flow mode of water at outlet  2 . In one illustrative embodiment, mode sensor  120  is a piezoelectric element for detecting changes in pressure pulses or vibrations to indicate when the mode changes between stream and spray. For example, faucet  10  may be configured to start in a default or baseline mode, such as the spray mode, and mode sensor  120  is configured to detect a change in pressure and/or vibrations which indicate that the mode has changed. In a further illustrative embodiment, mode sensor  120  may operate in conjunction with a capacitive sensor  138 , using touch or proximity sensing, in order to toggle between the stream mode and the spray mode. Additionally, capacitive sensor  138  may be used to tum faucet  10  on and off (i.e., start and stop the flow of water through waterway assembly  24 ), as detailed further hereinafter. 
     Outlet  2  may also include an aerator of the laminar-type (not shown) to change the water at outlet  2  between an aerated flow and a laminar flow. The aerator may include a plurality of openings that are configured to rotate and form various patterns or adjust the flow mode to promote either an aerated or a laminar flow. For example, rotating the aerator to align all of the openings may produce a laminar flow. Additionally, the aerator may include electronic sensors or mechanical couplings to toggle between aerated and laminar flow. 
     As shown in  FIGS. 1-3 , water treatment assembly  50  of faucet  10  further comprises a cover  52  supported under sink deck  5 , a printed circuit board  56 , a water treatment device  58 , illustratively an antibacterial device such as an ozone generator, and an electrically operable valve  60 . Water treatment housing  54  is positioned within cover  52 . Optionally, cover  52  may be surrounded by a shell  62  ( FIG. 1 ). Shell  62  may be formed as a single unit or may include first and second sides  62   a,    62   b  that couple together about the perimeter of shell  62 . Although the disclosure is described in connection with ozone treatment, it should be understood that additional types of fluid treatment may be used. 
     With respect to  FIGS. 2 and 5 , cover  52  illustratively includes a first side  52   a  and a second side  52   b  which are generally mirror images and represent approximately half of cover  52 . First and second sides  52   a,    52   b  are coupled about the perimeter of cover  52  to illustratively form a cube having a generally square cross-section. However, cover  52  may form other shapes. Alternatively, cover  52  may be formed as a single unit. Additionally, cover  52  and shell  62  may be formed of non-conductive materials, such as polymers. 
     Referring to  FIGS. 2-6 , water treatment housing  54  includes an inlet waterway  64  and an outlet waterway  66 . Inlet and outlet waterways  64 ,  66  may be oriented in close proximity to each other but not directly aligned. More particularly, illustrative inlet waterway  64  may be laterally offset from outlet waterway  66  such that inlet waterway  64  and outlet waterway  66  are substantially parallel. By positioning inlet and outlet waterway  64 ,  66  in close proximity to each other, water treatment housing  54  may be more compact. Alternatively, inlet and outlet waterways  64 ,  66  of water treatment housing  54  may be angled relative to each other. 
     As shown in  FIGS. 2, 3, 5, and 6 , a filter or screen  112  may be positioned within inlet waterway  64  of water treatment housing  54 . Filter  112  may be comprised of a finely-woven mesh material in order to remove impurities and other particulate matter from the water. As such, filter  112  may improve the quality of the water. Additionally, filter  112  may increase the uniformity of the water. 
     Referring to  FIGS. 2-5 , water treatment housing  54  extends from above an upper surface  68  of cover  52  and below a lower surface  70  of cover  52 . More particularly, upper surface  68  of cover  52  includes an aperture  72  through which inlet waterway  64  of water treatment housing  54  extends and lower surface  70  of cover  52  includes an aperture  74  through which outlet waterway  66  of water treatment housing  54  extends. Water treatment housing  54  may include a valve cavity  76  and a treatment cavity  84 . Treatment cavity  84  is aligned with valve cavity  76  and may be spaced apart therefrom by a wall  106  of water treatment housing  54 . More particularly, valve cavity  76  and treatment cavity  84  are substantially perpendicular to inlet and outlet waterways  64 ,  66  of water treatment housing  54 . Treatment cavity  84  extends toward a lateral surface  86  of cover  52  and extends through an aperture  88  in lateral surface  86 . 
     Referring to  FIGS. 2A-4A , valve cavity  76  supports electrically operable valve  60 , which may be coupled to water treatment housing  54  and circuit board  56  via conventional fasteners, for example a plurality of screws  61 , and/or adhesive materials. Electrically operable valve  60  extends substantially perpendicularly to inlet waterway  64  and outlet waterway  66  of water treatment housing  54 . Electrically operable valve  60  may be an electromechanical valve, illustratively a solenoid valve, that converts energy into linear motion. Illustratively, electrically operable valve  60  includes a magnetic portion  78 , a plunger  80 , and a valve member  82 . More particularly, plunger  80  is positioned within magnetic portion  78  and valve member  82  is spaced apart from magnetic portion  78 . Valve member  82  includes a first side  82   a  that is comprised of magnetic material (e.g., metal) and a second side  82   b  that is comprised of a non-conductive sealing material (e.g., rubber). Electrically operable valve  60  is electrically coupled to an external power supply  146  (e.g., the electrical system of the house, building, or other structure in which faucet  10  is used) (not shown). 
     Illustratively, electrically operably valve  60  further includes a spring mechanism  275  ( FIG. 11 ) within magnetic portion  78  that is adjacent to an end of plunger  80 , such that plunger  80  is spring-biased within magnetic portion  78 . In particular, plunger  80  is spring-biased toward a closed position. In other words, electrically operable valve  60  is closed when no power is supplied thereto and plunger  80  may extend from magnetic portion  78 . Additionally, spring mechanism  275  ( FIG. 11 ) is extended and not compressed by plunger  80 . More particularly, in the closed position, plunger  80  contacts first side  82   a  of valve member  82 , thereby pushing or propelling valve member  82  toward a valve seat  83  of wall  106  ( FIGS. 4A, 4B ). As such, second side  82   b  of valve member  82  is sealingly engaged with valve seat  83  to prevent water from flowing into valve cavity  76 . 
     Conversely, during operation, a voltage is applied to magnetic portion  78  to form a magnetic field along plunger  80  when faucet  10  is operating. The magnetic field causes plunger  80  to slide or retract within magnetic portion  78  to open or actuate electrically operable valve  60 . When electrically operable valve  60  is in the open position, plunger  80  retracts within magnetic portion  78  and compresses spring mechanism  275  ( FIG. 11 ). As such, when electrically operable valve  60  is operating, plunger  80  is spaced apart from valve member  82 , thereby allowing the water pressure of the water in inlet waterway  64  to create a pressure differential in valve cavity  76  and push valve member  82  away from valve seat  83  and toward plunger  80  and magnetic portion  78 . During operation, electrically operable valve  60  may generate heat and, therefore, a heat sink  114  may be coupled to circuit board  56  and positioned near electrically operable valve  60 . Cover  52  may include a plurality of narrow openings or slits  116  in at least upper surface  68  adjacent heat sink  114  to vent heat produced by electrically operable valve  60 . 
     With continued to reference to  FIGS. 3, 4A, and 4B , treatment cavity  84  removably supports a treatment device, illustratively water treatment device  58 , therein. Illustrative water treatment device  58  may be a filter device, an antibacterial device, or any other device configured to treat a fluid within faucet  10 . Antibacterial devices are configured to kill or inhibit the growth of bacteria, for example in foods or on inanimate surfaces or hands (See http://www.fda.govIFood/ResourcesForYou/StudentsTeachers/Science andTheFoodSupply/ucm2 15830.htm). Illustratively, antibacterial devices may use chemical treatments (e.g., chlorine), additives, ozone, UV, and other known methods to kill or inhibit growth of bacteria. 
     Illustratively, water treatment device  58  is an antibacterial ozone generator configured to output a treatment with activity against bacteria into the water. Water treatment device  58  is positioned upstream from outlet tube  30  and is housed within a sleeve  90 . Sleeve  90  and water treatment device  58  extend along a longitudinal axis   of treatment cavity  84  ( FIGS. 3 and 6 ). An open threaded end  96  of treatment cavity  84  is threadedly coupled to a threaded fastener or cap  98  (e.g., a nut) to retain sleeve  90  within treatment cavity  84 . Sleeve  90  may further include at least one groove  100  to receive a sealing member  102 . Illustratively, a first end  94  of sleeve  90  includes first and second grooves  100  to receive first and second sealing members  102  (e.g., o-rings). 
     Water treatment device  58  illustratively includes at least one channel  118 , an ozone production device, illustratively a pill  59 , and electric couplers, illustratively cables or wires  92 . Wires  92  extend from first end  94  of sleeve  90 . Illustratively, water treatment device  58  includes first and second channels  118   a,    118   b  that may be substantially parallel to longitudinal axis   of treatment cavity  84  ( FIG. 3 ). Additionally, pill  59  of water treatment device  58  may be intermediate channels  118   a,    118   b.  In operation, water flows between valve cavity  76  and treatment cavity  84  and is separated such that a portion of the water flows through water treatment device  58  and a portion of the water side streams through channels  118   a,    118   b . As shown in  FIG. 4A , side streaming water is illustratively denoted by arrows  150 A and as such, bypasses water treatment device  58 . The water flowing through water treatment device  58  is illustratively denoted by arrows  150 B and may be treated, for example with ozone, if water treatment device  58  is operating. As shown in  FIG. 4A , arrows  150 A and  150 B indicate that the treated water and the non-treated water flow in generally coaxial directions during operation of faucet  10 . The side streaming water  150 A and the water  150 B flowing through water treatment device  58  mix together in second portion  30   b  of outlet tube  30 . When faucet  10  of the present disclosure is operating (i.e., electrically operable valve  60  is in the open position), a portion of the water flowing through water treatment housing  54  side streams and a portion of the water flows through water treatment device  58 , regardless of whether water treatment device  58  is operating. In particular, the side streaming water  150 A may minimize the pressure drop within a water passageway  110  of water treatment housing  54 . 
     With continued reference to  FIGS. 4A and 4B , wall  106  of water treatment housing  54  is positioned intermediate treatment cavity  84  and valve cavity  76 . Wall  106  may abut a second end  104  of sleeve  90  to prevent sleeve  90  and water treatment device  58  from extending into valve cavity  76 . More particularly, wall  106  includes openings  108  that regulate and control water flowing between valve cavity  76  and treatment cavity  84 . Optionally, a spacer (not shown) having at least one opening or window may be positioned between second end  104  of sleeve  90  and wall  106  in order to further regulate and control the volume of water that flows between valve cavity  76  and treatment cavity  84 . In particular, openings  108  control and regulate the volume of water  150 B that flows through water treatment device  58  and the volume of water  150 A that side streams. 
     Referring to  FIGS. 3, 4A, and 4B , water passageway  110  of water treatment housing  54  extends between inlet waterway  64  and outlet waterway  66  and between valve cavity  76  and treatment cavity  84 . Illustratively, water passageway  110  has a generally serpentine shape. More particularly, water passageway  110  is substantially vertical through inlet waterway  64  and includes a substantially right-angle bend and continues into valve cavity  76 . Water passageway  110  continues from valve cavity  76 , through openings  108  in wall  106 , and extends into treatment cavity  84 . Water passageway  110  includes another substantially right-angle bend in treatment cavity  84  and is substantially vertical through outlet waterway  66 . By including another substantially right-angle bend, a return passageway of water passageway  110  reverses the flow direction of the water, which illustratively reduces the distance between inlet waterway  64  and outlet waterway  66 . Additionally, the return passageway may be approximately parallel to treatment cavity  84 , thereby further decreasing the size of water treatment housing  54 . 
     To limit contact between the water in faucet  10  and metallic components, water treatment housing  54  may be formed of a flexible, non-metallic material, such as a polymer, illustratively a cross-linkable polymer. Alternatively, water treatment housing  54  may be lined with a non-metallic material. As such, water treatment housing  54  is illustratively electrically non-conductive. In one illustrative embodiment, substantially the entire water treatment housing  54  is formed of a polyethylene which is subsequently cross-linked to form cross-linked polyethylene (PEX). Other suitable materials that may be used to construct water treatment housing  54  include polyethylene (PE) (such as raised temperature resistant polyethylene (PE-RT)), polypropylene (PP) (such as polypropylene random (PPR)), and polybutylene (PB). It is further envisioned that water treatment housing  54  may be constructed of cross-linked polyvinyl chloride (PVCX) using silane free radical initiators, cross-linked polyurethane, or cross-linked propylene (XLPP) using peroxide or silane free radical initiators. It is within the scope of the present disclosure that the polymer material used to construct water treatment housing  54  may include reinforcing members, such as glass fibers. 
     Water treatment device  58  may be used to produce ozone (03) that absorbs into the water in water treatment housing  54 . Water treatment device  58  may be configured to produce ozone through conventional methods (e.g., corona discharge or “hot spark,” electrolysis, plasma, UV). Faucet  10  may further include an aspirator (not shown) to facilitate the treatment of the water. 
     Illustratively, water treatment device  58  uses an electrolytic process which allows ozone to be produced under pressure, and therefore, may increase the concentration of ozone in the water relative to other ozone production methods. In particular, an electric current is supplied to wires  92  and is transmitted to pill  59  of water treatment device  58  in order to produce ozone. Wires  92  are electrically coupled to external power supply  146 . Exemplary ozone generators  58  may be available from EOI Electrolytic Ozone Inc. or Klaris Corporation Inc. Because water treatment device  58  is positioned under sink deck  5 , sufficient time is permitted for the ozone to be absorbed by the water in second portion  30   b  of outlet tube  30  before the ozone-treated water is delivered from outlet  2 . For example, outlet tube  30  may be approximately 36 inches in length in order to allow the ozone to be dissolved or absorbed in the water before reaching outlet  2 . In addition to ozone, water treatment device  58  also may be configured to treat the water in other ways and/or with other chemicals. For example, controller  136  may be configured to alter the treatment produced by water treatment device  58  in response to a user input or desired fluid application. 
     When water treatment device  58  is configured to produce ozone, the ozone-treated water at outlet  2  is preferably used as a disinfectant or cleaning agent. Additionally, the ozone-treated water may be used to disinfect drinking water. More particularly, until the ozone dissolved in the water is destroyed or otherwise destructed, the ozone-treated water performs a disinfecting function (i.e., actively disinfects objects in contact with the water). Alternatively, if the ozone dissolved in the water is destroyed, the ozone-treated water remains disinfected or clean; however, the ozone-treated water no longer actively performs a disinfecting function. For example, disinfected ozone-treated water may be preferable for clean drinking water applications, whereas ozone-treated water that actively performs a disinfecting function may be preferable as a cleaning agent. 
     Faucet  10 , and in particular waterway assembly  24 , may include a filter  113  ( FIGS. 17A and 17B ) downstream from water treatment device  58 . Filter  113  may be configured to further improve the quality of the water by removing impurities or other particles. Additionally, filter  113  may be, for example, a carbon black filter, may be configured to destroy or destruct the ozone in the water in second portion  30   b  of outlet tube  30 . As such, the water in second portion  30   b  of outlet tube  30  is treated with ozone and is disinfected or clean as it is delivered from outlet  2 . However, when the ozone in the water is destroyed by filter  113 , the water delivered from outlet  2  no longer actively disinfects objects in contact with the water. Controller  136  may be operably coupled to filter  113  to control operation of filter  113  and/or the flow of water through filter  113  (i.e., through a bypass valve). As such, a user may selectively operate filter  113  in order to produce disinfected water for particular clean water applications (e.g., drinking) and disinfecting water for other water applications (e.g., cleaning). 
     Referring to  FIGS. 1, 3, and 7 , controller  136  may receive input from sensors or other ozone user inputs  134  to tum water treatment device  58  on and off. Illustratively, user input  134  is a mechanical push button on pedestal  36 . Alternatively, user input  134  may be a capacitive sensing button. Controller  136  electrically controls the operation of water treatment device  58  and may include a timer or clock  142  to tum off water treatment device  58  after a predetermined length of time of operation. For example, controller  136  may be configured to tum off water treatment device  58  after four consecutive minutes of operation. Additionally, clock  142  may record a cumulative amount of time that water treatment device  58  has been operating within a predetermined period. For example, when water treatment device  58  cumulatively operates for approximately 15 minutes during a 60-minute period, clock  142  may send a signal to controller  136 . In response thereto, controller  136  may prevent water treatment device  58  from operating until water treatment device  58  has been inactive for a predetermined time. 
     Additionally, clock  142  may be configured as a water treatment retention timer. More particularly, controller  136  may cooperate with clock  142  to continue operation of water treatment device  58  when a user accidentally bumps or taps spout  12 , thereby accidentally turning off the water. For example, when water flows from outlet  2  and user input  134  is activated, controller  136  activates water treatment device  58  to deliver treated water from outlet  2 . However, if a user accidentally bumps or taps spout  12  while water treatment device  58  is operating, thereby turning off the water, and then subsequently taps spout  12  again within a predetermined time period, the water will tum on and treated water will continue to flow from outlet  2 . As such, controller  136  continues operation of water treatment device  58  for a predetermined time (e.g., 30 seconds) after spout  12  receives a tap to tum water off. If the user does not tap spout  12  within the predetermined time period to tum on the water again, thereby indicating that the user did not accidentally tum off the water, controller  136  will stop operation of water treatment device  58 . It may be appreciated that controller  136  may differentiate between a tap on spout  12  for controlling operation of faucet  10  and a grab on spout  12  for adjusting the position of spout  12 . In particular, spout  12  is configured to swivel or rotate and a user may adjust the position of spout  12  without turning on/off the water. 
     Faucet  10  also may include a display or other signal (not shown) operably coupled to user input  134  to indicate to a user whether water treatment device  58  is operating. For example, faucet  10  may include a light-emitting diode (“LED”) display on pedestal  36  that may use a specific color to indicate if water treatment device  58  is active (i.e., turned on). In other illustrative embodiments of the present disclosure, user input  134  may be backlit and illuminates to indicate that water treatment device  58  is operating. For example, user input  134  may be backlit to illuminate a white light when water treatment device  58  is operating. Additionally, user input  134  may include a temperature indicator, for example a blue light for cold water and a red light for hot water. Additionally, user input  134  may be configured to gradually change from red to blue or blue to red to indicate a respective decrease or increase in the temperature of the water, as measured by thermistor  122 . 
     Alternatively, capacitive sensor  138  and controller  136  may be used to operate water treatment device  58  and/or actuate electrically operable valve  60  through touch or proximity sensing technology. As such, capacitive sensor  138 , in combination with controller  136 , may be configured to monitor and control the operation of both electrically operable valve  60  and water treatment device  58 . Capacitive sensor  138  may comprise a hands-free proximity sensor, such as an infrared sensor coupled to spout  12 , or a touch sensor, such as an accelerometer, force sensor, or push button, to control activation of electrically operable valve  60  and/or water treatment device  58  in a manner similar to that disclosed in U.S. Patent Application Publication No. 2011/0253220 to Sawaski et al., the disclosure of which is expressly incorporated by reference herein. More particularly, capacitive sensor  138  also may comprise an electrode (not shown) coupled to spout body  12 . The side wall of spout body  12  may be formed of an electrically conductive material (e.g., metal) and define the electrode. In other illustrative embodiments, the electrode may be defined by a separate electrically conductive element, such as a metal plate. Any suitable capacitive sensor  138  may be used, such as a CapSense capacitive sensor available from Cypress Semiconductor Corporation. 
     An output from capacitive sensor  138  is coupled to controller  136 . More particularly, controller  136  may determine whether a touch (tap or grab) is detected on spout body  12  and/or whether a user&#39;s hands or other object is within a detection area proximate spout body  12 . For example, if capacitive sensor  138  is operating with the touch sensor, when a touch is detected on spout body  12 , controller  136  determines the touch pattern (number of touches) before implementing different functions of faucet  10 . Controller  136  may determine that a single tap was detected on spout body  12 , thereby indicating that electrically operable valve  60  should be turned on or off. Alternatively, controller  136  may determine that two taps (a double tap) were detected on spout body  12  within a predetermined time period (e.g., one second), thereby indicating that water treatment device  58  should be turned on or off. 
     The illustrative embodiment faucet  10  may operate according to the following example. When electrically operable valve  60  is closed, faucet  10  does not operate. A single tap on spout body  12  may activate operating electrically operable valve  60 . However, a double tap on spout body  12  may activate both electrically operable valve  60  and water treatment device  58 , such that the water at outlet  2  is treated with ozone. Only a single tap on spout body  12  may be required to simultaneously tum off both electrically operable valve  60  and water treatment device  58 . Furthermore, if electrically operable valve  60  is activated, a double tap on spout body  12  may tum water treatment device  58  on and off. However, a double tap on spout body  12  will not tum off electrically operable valve  60 , such that only operation of water treatment device  58  may be affected by a double tap on spout body  12 . As is further detailed below, water treatment device  58  will not operate when electrically operable valve  60  is not operating. 
     The effectiveness of water treatment device  58  is proportional to the concentration of ozone in the water. For example, the oxidation-reduction potential (“ORP”) (i.e., the cleanliness) of the water treated with ozone may be one method of determining the effectiveness of water treatment device  58 . Similarly, the “kill-rate” of the ozone in the water indicates the effectiveness of water treatment device  58  and measures the amount of contaminants in the water. Faucet  10  may include a quality sensor  144  ( FIG. 7 ) to measure the ORP and/or the kill-rate, thereby monitoring the effectiveness of water treatment device  58 . 
     Referring to  FIGS. 2, 3, and 5-7 , the concentration of ozone in the water, and therefore, the effectiveness of water treatment device  58 , may be affected by parameters or properties of the water, such as flow rate, temperature, the flow mode at outlet  2 , and the amount of power supplied to water treatment device  58 . As such, faucet  10  further includes a temperature sensor, illustratively a thermistor  122 , and a flow rate sensor assembly  124 , which illustratively includes a turbine  126  and a Hall-Effect sensor  128 . Controller  136  monitors and controls the operation of water treatment device  58  in response to signals sent by thermistor  122  and flow rate sensor assembly  124  indicating the corresponding values for the water. Additionally, faucet  10  may include a power sensor  140  to monitor the power available to electrically operable valve  60  and water treatment device  58 . 
     Thermistor  122  may be positioned within a thermistor retainer  123  coupled to inlet waterway  64  of water treatment housing  54 . More particularly, thermistor  122  is positioned upstream to valve cavity  76  and treatment cavity  84  in order to monitor the temperature of the water before it flows to water treatment device  58 . Illustratively, thermistor  122  is oriented perpendicularly to inlet waterway  64  of water treatment housing  54 , however thermistor  122  may be positioned in a different orientation, depending on the configuration of water treatment housing  54 . 
     The temperature of the water is inversely related to the concentration of ozone in the water. In particular, as the temperature of the water increases, the concentration of ozone in the water may decrease due to undesirable off-gassing. When controller  136  receives a temperature measurement from thermistor  122  that is greater than a predetermined maximum temperature, such that the temperature of the water will adversely affect the concentration of ozone in the water, controller  136  may prevent water treatment device  58  from operating. As such, if water treatment device  58  is activated when the water temperature is equal to or greater than the predetermined maximum temperature, user input  134  may indicate to a user that water treatment device  58  has not been turned on. Additionally, due to the inverse relationship between ozone concentration and temperature of the water, water treatment device  58  is positioned downstream of valve assembly  20 . More particularly, if an ozone production device is positioned within hot and cold inlet tubes  26 ,  28 , the water would not yet be mixed in valve assembly  20  and the concentration of ozone in the hot water may be diminished relative to the concentration of ozone in the cold water. By positioning water treatment device  58  downstream from valve assembly  20 , the concentration of ozone in the water may be more uniform and the effectiveness of water treatment device  58  may increase. Further, turbine  126  of flow rate sensor assembly  124  helps mix hot and cold water and is, therefore, upstream of thermistor  122 . 
     Similarly, and as shown in  FIGS. 2 and 5-7 , the flow rate of the water may affect the concentration of ozone in the water, and therefore, the effectiveness of water treatment device  58 . More particularly, when the flow rate of the water is low, undesirable off-gassing may occur. Additionally, when the flow rate of the water is high, the concentration of the ozone in the water may be adversely affected (i.e., too low), thereby also decreasing the effectiveness of water treatment device  58 . As such, in certain illustrative embodiments, controller  136  may be operably coupled to flow rate sensor assembly  124  and water treatment device  58  in order to proportionally adjust the ozone output relative to the flow rate. Furthermore, the flow rate may be correlated to the volume of water requested and/or the capacity of faucet  10  and water treatment device  58 . 
     Turbine  126  of flow rate sensor assembly  124  may be positioned within inlet waterway  64  of water treatment housing  54  and aligned with Hall-Effect sensor  128 , which is external to inlet waterway  64 . More particularly, Hall-Effect sensor  128  is positioned intermediate inlet waterway  64  and circuit board  56 . Additionally, flow rate sensor assembly  124  may be adjacent to and downstream from filter  112 . Flow rate sensor assembly  124  is positioned upstream to valve cavity  76  and treatment cavity  84  in order to monitor the flow rate of the water before entering treatment cavity  84 . 
     During operation, when water flows through inlet waterway  64  of water treatment housing  54 , flow rate sensor assembly  124  monitors the flow rate of the water and electrically communicates a signal to controller  136 . More particularly, turbine  126  facilitates mixing of the hot and cold water entering water treatment housing  54  by rotating as the water passes through. Hall-Effect sensor  128  detects the number of rotations made by turbine  126  during a predetermined time period and transmits a signal to controller  136  indicative thereof. Controller  136  is configured to equate the number of rotations of turbine  126  to a particular flow rate of the water. When the flow rate of the water is within a desired operating range, for example between 0.01-2.5 gallons/minute, water treatment device  58  will not operate. For example, if water treatment device  58  is turned on while the flow rate is lower than the predetermined minimum rate (e.g., 0.01 gallons/minute), controller  136  prevents water treatment device  58  from operating. Similarly, if ozone generator is turned on while the flow rate is greater than the predetermined maximum rate (e.g., 2.5 gallons/minute), controller  136  also prevents water treatment device  58  from operating. Alternatively, the maximum flow rate may be controlled by a flow restrictor, for example flow restrictor  200  ( FIG. 17A ), which maintains the flow rate at or below the predetermined maximum flow rate. If the flow rate is not within the operating range, user input  134  may indicate to a user that water treatment device  58  has not been activated. Also, it may be understood that water treatment device  58  will not operate if electrically operable valve  60  is not operating. 
     In alternative embodiments, controller  136  may be configured to control operation of water treatment device  58  to proportionally increase or decrease the production of ozone relative to the flow rate and/or the temperature of the water. In particular, pill  59  of water treatment device  58  may be operated by controller  136  to optimize the production of ozone such that the concentration of ozone absorbed into the water also is optimized based upon the detected flow rate and temperature of the water. 
     The flow modes of the water at outlet  2 , or variations thereof, also may affect the concentration of ozone in the water. More particularly, the turbulence of the water is inversely related to the concentration of ozone in the water. As the turbulence of the water increases, the concentration of ozone in the water may decrease. As detailed above, the stream mode produces a more laminar, less turbulent flow of water at outlet  2  when compared to the spray mode. Additionally, the water is less turbulent when the aerator produces a laminar stream. As such, mode sensor  120  may send a signal to controller  136  to prevent water treatment device  58  from operating when spray head  15  is in a spray mode, when the aerator is in an aerated mode, or in another mode that may increase the turbulence of the water. If water treatment device  58  is turned on when spray head  15  is in the spray mode, for example, controller  136  will prevent water treatment device  58  from operating and user input  134  may indicate to a user that water treatment device  58  has not been activated. 
     Furthermore, it may be appreciated that water treatment device  58  is positioned in an unrestricted portion of waterway assembly  24 . For example, filter  112 , flow rate assembly  124 , and electrically operable valve  60  may restrict water flow or narrow water passageway  110 , which may increase the turbulence of the water. However, water treatment device  58  is positioned downstream of filter  112 , flow rate assembly  124 , and electrically operable valve  60 , thereby ensuring that the turbulence in the water is minimized before the water enters water treatment device  58 . Additionally, ozone in the water may adversely affect components of faucet  10 , for example valve disc  82 . In particular, ozone may erode the material comprising valve disc  82 . Therefore, by positioning water treatment device  58  downstream from electrically operable valve  60 , damage to valve disc  82  and other components of faucet  10  may be minimized. 
     Additionally, power sensor  140  is illustratively in electrical communication with controller  136  and wires  92  of water treatment device  58  ( FIG. 7 ). As such, power sensor  140  monitors the power (e.g., electric current) supplied to water treatment device  58  because the current flowing through pill  59  is proportional to the concentration of ozone produced by water treatment device  58 . More particularly, if the current is lower than a predetermined amount, no ozone may be produced by water treatment device  58 . As detailed above, a low concentration of ozone decreases the effectiveness of water treatment device  58 . Therefore, if water treatment device  58  is turned on when the current supplied to water treatment device  58  is below a predetermined minimum level, controller  136  will prevent water treatment device  58  from operating. User input  134  may indicate to a user that water treatment device  58  has not been activated. For example, if external power supply  146  loses power, no current is supplied to water treatment device  58 , and controller  136  prevents water treatment device  58  from operating. 
     Controller  136  also may communicate with a secondary or back-up power source, illustratively battery  130 , coupled to cover  52  and electrically coupled to electrically operable valve  60 . More particularly, if external power supply  146  loses power, electrically operable valve  60  may be prevented from operating. However, battery  130  or other secondary power system may provide electricity to electrically operable valve  60  in the event of a power loss. Battery  130  is illustratively a qV battery that is coupled to lower surface  72  of cover  52 . More particularly, lower surface  72  of cover  52  includes a cover  132  extending downwardly therefrom and generally surrounding battery  130 . The illustrative embodiment of cover  132  includes a first side  132   a  and a second side  132   b  that are coupled together to form cover  132  around battery  130 . However, cover  132  may be constructed as a single piece that is configured to receive battery  130 . Illustrative battery  130  is not coupled to water treatment device  58  and, therefore, may not supply power to water treatment device  58 . As such, water treatment device  58  will not operate during a power loss even when electrically operable valve  60  is operating via battery  130  and water is flowing from outlet  2 . 
     As detailed herein, and with reference to  FIG. 7 , controller  136  monitors and controls the operation of water treatment device  58 . More particularly, controller  136  receives input signals from at least thermistor  122 , flow rate sensor assembly  124 , mode sensor  120 , and power sensor  140  in order to determine when, and if, water treatment device  58  may be prevented from operating. For example, when the temperature of the water is greater than a predetermined maximum, when the flow rate of the water is not within the operating range, when the flow mode at outlet  2  is defines a spray mode, and when no power is supplied to water treatment device  58 , controller  136  will output a signal to prevent water treatment device  58  from operating. Controller  136  also may be in electrical communication with quality sensor  144 . 
     Referring to  FIGS. 1, 3, 4A, 4B, and 7 , in use, hot and cold water flows from hot and cold water supplies  6 ,  8 , through hot and cold inlet tubes  26 ,  28 , to valve assembly  20  of faucet  10 . The water mixes in valve assembly  20  and flows downward through first portion  30   a  of outlet tube  30  toward water treatment housing  54 . The water enters inlet waterway  64  of water treatment housing  54  flowing through filter  112  and turbine  126  of flow rate sensor assembly  124 , and flowing past thermistor  122 . The water bends at a generally right angle to enter valve cavity  76 . Electrically operable valve  60  is operated and the water pressure pushes valve member  82  toward plunger  80 , thereby allowing water to flow through valve cavity  76  and openings  108  in wall  106  toward treatment cavity  84 . 
     Water enters treatment cavity  84  and a portion of the water  150 A ( FIG. 4A ) side streams, or bypasses water treatment device  58 , and a portion of the water  150 B ( FIG. 4A ) enters channels  118   a,    118   b  of water treatment device  58 . The water flows from treatment cavity  84  and bends at a generally right angle to flow downwardly toward outlet waterway  66  of water treatment housing  54 . The water  150 A,  150 B leaving treatment cavity  84  flows in a reverse direction relative to the water entering treatment cavity  84 . The water continues to flow through second portion  30   b  of outlet tube  30  toward spray head  15  and outlet  2 . The water at outlet  2  may be a spray, a stream, or aerated, depending on the mode selected. 
     Referring to  FIG. 4A , as water flows through water treatment housing  54 , flow rate sensor assembly  124  and thermistor  122  may each electrically communicate a signal to controller  136  indicative of the respective flow rate and temperature of the water. Additionally, controller  136  may receive a signal from mode sensor  120  indicative of the flow mode of the water. If water treatment device  58  is not operating (i.e., user input  134  or capacitive sensor  138  was not activated and no signal was sent to controller  136  to activate water treatment device  58 ), no ozone is generated as water flows through channels  118   a,    118   b  of water treatment device  58 . The side streaming water then mixes with the water exiting channels  118   a,    118   b  and combines to flow toward outlet waterway  66 , through outlet tube  30 , and toward spray head  15  and outlet  2 . 
     However, if user input  134  or capacitive sensor  138  sends a signal to controller  136  indicating that ozone generation is requested, controller  136  determines if the flow rate is within the operating range and, likewise, if a temperature of the water is below a predetermined maximum temperature. Additionally, controller  136  determines if the flow mode of the water defines a stream and if power is available for water treatment device  58 . If the flow rate is within the operating range, the temperature of the water is below the predetermined maximum temperature, the flow mode is a stream, and power is available, controller  136  will activate water treatment device  58 . As such, and with reference to  FIG. 4A , power is supplied to water treatment device  58 , in particular to pill  59 , in order to produce ozone as the water flows through water treatment device  58 . Pill  59  mixes ozone into the water in channels  118   a,    118   b.  The ozone-treated water mixes with the side streaming water flowing around sleeve  90  water in second portion  30   b  of outlet tube  30  to deliver water to outlet  2 . 
     Conversely, if controller  136  determines that the temperature of the water is greater than the predetermined temperature, that the flow rate is not within the operating range, that the water at outlet  2  is in the spray mode, or that insufficient power is available to water treatment device  58 , controller  136  prevents water treatment device  58  from operating. User input  134  may indicate that water treatment device  58  is not operating. As such, water flowing through channels  118   a,    118   b  of water treatment device  58  is not treated with ozone. 
     As shown in  FIG. 4B , when faucet  10  is turned off, electrically operable valve  60  does not operate and no power is supplied to electrically operable valve  60 . As such, valve member  82  seals against valve seat  83  to prevent water from entering valve cavity  76 . When electrically operable valve  60  is not operating, water may not flow through outlet tube  30  or spray head  15  and water treatment device  58  is not activated. 
     With reference to  FIGS. 2 and 3 , to service or replace water treatment device  58 , cap  98  is removed from first end  96  of treatment cavity  84 . Sleeve  90 , including water treatment device  58  positioned therein, may be slidably removed from treatment cavity  84  along longitudinal axis  . As such, sleeve  90  allows water treatment device  58  to be removed from water treatment housing  54  without accessing the interior of cover  52 . Similarly, water treatment device  58  and sleeve  90  may be coupled to water treatment housing  54  by sliding sleeve  90  along longitudinal axis   and coupling cap  98  to first end  96  of treatment cavity  84 . 
     Referring next to  FIGS. 8-13 , another illustrative embodiment faucet  10 ′ is shown. Faucet  10 ′ of  FIGS. 8-13  includes features similar to those of faucet  10  of  FIGS. 1-7 , with like reference numerals indicating like elements, except as described below. Similar to faucet  10 , illustrative faucet  10 ′ includes spout body  12 , hub  14 , spray head  15 , valve assembly  20 , a waterway assembly  24 ′, mounting assembly  35 , a water treatment assembly  50 ′, and controller  136  ( FIG. 7 ). In operation, faucet  10 ′ receives water from hot and cold water supplies  6  and  8 , respectively, and selectively mixes the incoming water in valve body  32  to provide water to outlet  2  at spray head  15 . Faucet  10 ′ may be mounted to sink deck  5  with mounting assembly  35  and is arranged to direct water from outlet  2  into sink basin  1 , for example. Water treatment assembly  50 ′ may be easily added to faucet  10 ′ without disrupting the configuration of other components of faucet  10 ′. 
     With reference to  FIG. 8 , illustrative waterway assembly  24 ′ of faucet  10 ′ includes hot water inlet tube  26  fluidly coupled to a stop valve  282  ( FIGS. 17A and 17B ), a cold water inlet tube  28 ′ fluidly coupled to a stop valve  280  ( FIGS. 17A and 17B ), and outlet tube  30 . Hot and cold water inlet tubes  26 ,  28 ′ of waterway assembly  24 ′ are fluidly coupled to hot and cold water supplies  6 ,  8 , respectively, for receiving water into faucet  10 ′. Hot water inlet tube  26  may include a check valve  288  ( FIGS. 17A and 17B ). Cold water inlet tube  28 ′ includes a first portion  28   a ′, a second portion  28   b ′, and a third portion  28   c ′. Cold water inlet tube  28 ′ also includes a multi-directional flow member, illustratively a T-member  152 . T-member  152  includes a first portion  152   a  extending in an illustratively vertical direction and a second portion  152   b  extending generally perpendicularly from first portion  152   a.  First portion  28   a ′ of cold water inlet tube  28 ′ extends between cold water supply  8  and a bottom end of first portion  152   a  of T-member  150 . Third portion  28   c ′ of cold water inlet tube  28 ′ may include a check valve  284  ( FIGS. 17A and 17B ) and is fluidly coupled to valve assembly  20  and a top end of first portion  152   a  of T-member  150 . Both top and bottom ends of first portion  152   a  may include sealing members (not shown) for preventing water leaks between T-member  152  and cold water inlet tube  28 ′. 
     Second portion  28   b ′ of cold water inlet tube  28 ′ may include a check valve  286  ( FIGS. 17A and 17B ) and is fluidly coupled to water treatment assembly  50 ′ and second portion  152   b  of T-member  152 . Second portion  152   b  of T-member  152  may include sealing members (not shown) for preventing water leaks between T-member  152  and cold water inlet tube  28 ′. 
     Illustratively, outlet tube  30  includes first portion  30   a  and second portion  30   b . Both first and second portions  30   a,    30   b  of outlet tube  30  are fluidly coupled to water treatment assembly  50 ′. More particularly, first portion  30   a  extends between valve assembly  20  and a water treatment housing  54 ′ of water treatment assembly  50 ′. Second portion  30   b  extends below water treatment housing  54 ′ and bends upwardly to pass through spout body  12  in order to couple with spray head  15  and deliver water from outlet  2 . 
     To limit contact between the water in faucet  10 ′ and metallic components, waterway assembly  24 ′, including inlet tubes  26 ,  28 ′, outlet tube  30 , and T-member  152 , may be formed of, or lined with, a flexible, non-metallic material, such as a polymer, illustratively a cross-linkable polymer, as detailed above with respect to waterway assembly  24 . As such, waterway assembly  24 ′ is illustratively electrically non-conductive. 
     Referring to  FIG. 8 , spray head  15  may be a pull-down spray head, as detailed above, and is fluidly coupled to second portion  30   b  of outlet tube  30 . Spray head  15  may be configured to adjust the flow mode of the water at outlet  2 . The flow mode of operation may be a spray, a stream, an aerated mode, or any combination thereof, and may include additional flow outlet patterns. Spray head  15  may be mechanically or electrically coupled to mode sensor  120  in order to communicate the flow mode to controller  136 . More particularly, mode sensor  120  may be positioned on or within faucet  10  and may include a user input (not shown) to electrically toggle or switch between a stream mode, a spray mode, or other aerated modes, for example. A stream mode may output water from outlet  2  in a laminar, less turbulent manner than a spray mode. 
     As shown in  FIGS. 9 and 10 , water treatment assembly  50 ′ of faucet  10 ′ comprises water treatment housing  54 ′, a first printed circuit board  56 , a second printed circuit board  154 , water treatment device  58 ′, illustratively an ozone generator, a first electrically operable valve  60 , and a second electrically operable valve  156 . Water treatment housing  54 ′ includes cover members  54   a ′ and  54   b ′ which, when coupled together through latches  158  and latch openings  159 , generally surround first and second printed circuit boards  56 ,  154 , water treatment device  58 ′, and first and second electrically operable valves  60  and  156 . Faucet  10 ′ is configured to operate in either a treatment mode or a non-treatment mode. More particularly, when faucet  10 ′ is in the treatment mode, first electrically operable valve  60 , not second electrically operable valve  156 , is open. Conversely, when faucet  10 ′ is in the non-treatment mode, second electrically operable valve  156 , not first electrically operable valve  60 , is open. 
     Referring to  FIGS. 8-11 , water treatment assembly  50 ′ further includes an inlet waterway  64 ′ and an outlet waterway  66 ′. As detailed further below, outlet waterway  66 ′ includes a waterway tube  162  and is fluidly coupled to outlet tube  30 . Illustrative inlet waterway  64 ′ may be generally perpendicular to outlet waterway  66 ′ and is fluidly coupled to water treatment device  58 ′ and second portion  28   b ′ of cold water inlet tube  28 ′. Inlet waterway  64 ′ defines a treatment flow path  302  ( FIGS. 17A and 17B ) in which cold water from cold water supply  8  bypasses second electrically operable valve  156  and flows through water treatment device  58 ′ in order to flow treated water from outlet  2 . 
     As shown in  FIG. 11 , inlet waterway  64 ′ of water treatment assembly  50 ′ may support filter  112 , flow rate sensor assembly  124 , thermistor  122 , and a pressure-compensating flow restrictor  200  ( FIG. 17A ). Flow restrictor  200  may be available from Neoperl, Inc. and may be configured to restrict flow at a maximum rate of approximately 0.5 gallons/minute. 
     Filter  112  may be positioned within inlet waterway  64 ′ of water treatment assembly  50 ′ to remove impurities and other particulate matter from the water. As such, filter  112  may improve the quality of the water. Filter  112  also may increase the uniformity of the water. Additionally, flow rate sensor assembly  124  may be positioned within inlet waterway  64 ′. Illustratively, flow rate sensor assembly  124  is downstream from filter  112  and includes turbine  126  and Hall-Effect sensor  128  ( FIGS. 9 and 10 ). Thermistor  122  is supported by thermistor retainer  123  and a support member  160  on inlet waterway  64 ′ and is received within an aperture  194  ( FIG. 12 ). Flow rate sensor assembly  124  and thermistor  122  are electrically coupled to controller  136  ( FIG. 7 ). More particularly, flow rate sensor assembly  124  and thermistor  122  are electrically coupled to controller  136  via printed circuit board  56 . 
     Printed circuit board  56  and controller  136  also are electrically coupled to first electrically operable valve  60 . Referring to  FIGS. 9-11 , first electrically operable valve  60  is supported within valve cavity  76  and extends substantially perpendicularly to inlet waterway  64 ′ and waterway tube  162 . As shown in  FIG. 11 , fasteners  176  retain first electrically operable valve  60  within valve cavity  76 . First electrically operable valve  60  may be an electromechanical valve, illustratively a solenoid valve, for converting energy into linear motion. As detailed above, first electrically operable valve  60  includes magnetic portion  78 , plunger  80 , and valve member  82 . More particularly, plunger  80  is positioned within magnetic portion  78  and valve member  82  is spaced apart from magnetic portion  78 . First side  82   a  of valve member  82  is comprised of magnetic material (e.g., metal) and second side  82   b  of valve member  82  is comprised of a non-conductive sealing material (e.g., rubber). First electrically operable valve  60  is electrically coupled to external power supply  146  (e.g., the electrical system of the house, building, or other structure in which faucet  10 ′ is used) ( FIG. 7 ). 
     First electrically operably valve  60  further includes a spring mechanism  275  ( FIG. 11 ) within magnetic portion  78  such that plunger  80  is spring-biased toward a closed position. In other words, as shown in  FIG. 12 , first electrically operable valve  60  is closed when no power is supplied thereto and plunger  80  may extend from magnetic portion  78  in order to contact first side  82   a  of valve member  82  and push valve member  82  toward valve seat  83  ( FIGS. 12 and 13 ). As such, second side  82   b  of valve member  82  is sealingly engaged with valve seat  83  to prevent water from flowing into treatment cavity  84 . 
     As shown in  FIG. 13 , in order to open first electrically operable valve  60 , a voltage is applied to magnetic portion  78  to form a magnetic field along plunger  80  when faucet  10 ′ is operating. The magnetic field causes plunger  80  to slide or retract within magnetic portion  78  to open or actuate first electrically operable valve  60 . When first electrically operable valve  60  is in the open position, plunger  80  retracts within magnetic portion  78  and compresses spring mechanism  275  ( FIG. 11 ). As such, when first electrically operable valve  60  is operating, plunger  80  is spaced apart from valve member  82 , thereby allowing the water pressure of the water in inlet waterway  64 ′ to create a pressure differential in valve cavity  76  and push valve member  82  away from valve seat  83  and toward plunger  80  and magnetic portion  78 . During operation, first electrically operable valve  60  may generate heat and, therefore, heat sink  114  may be coupled to circuit board  56  and positioned near first electrically operable valve  60 . Cover member  54   b ′ may include slits  116  adjacent heat sink  114  to vent heat produced by first electrically operable valve  60 . 
     As shown in  FIG. 13 , treatment cavity  84  may be separated from valve cavity  76  by wall  106 . More particularly, wall  106  of water treatment housing  54 ′ is positioned intermediate treatment cavity  84  and valve cavity  76 . Wall  106  includes openings  108  that regulate and control water flowing between valve cavity  76  and treatment cavity  84 . Optionally, a spacer (not shown) having at least one opening or window may be positioned between sleeve  90  and wall  106  in order to further regulate and control the volume of water that flows between valve cavity  76  and treatment cavity  84 . As such, openings  108  control and regulate the volume of water that flows through water treatment device  58 ′. 
     With reference to  FIGS. 9-11 , treatment cavity  84  removably supports water treatment device  58 ′ therein. Illustrative water treatment device  58  may be a filter device, an antibacterial device, or any other device configured to treat a fluid within faucet  10 ′. Antibacterial devices are configured to kill or inhibit the growth of bacteria, for example, in foods or on inanimate surfaces or hands (See http://wwwfda.govIFood/ResourcesForYou/StudentsTeachers/ScienceandTheFoodSupply/ucm2 15830.htm). Illustratively, antibacterial devices may use chemical treatments (e.g., chlorine), additives, ozone, UV, and other known methods to kill or inhibit growth of bacteria. 
     Illustratively, water treatment device  58 ′ is an antibacterial ozone generator configured to output ozone into the water. Water treatment device  58 ′ is positioned upstream from outlet tube  30  and is housed within sleeve  90 . Threaded end  96  of treatment cavity  84  is threadedly coupled to cap  98  (e.g., a nut) to retain sleeve  90  and water treatment device  58 ′ within treatment cavity  84 . More particularly, cap  98  is directly coupled to, or integrally formed with, sleeve  90 , such that when cap  98  is removed from water treatment assembly  50 ′, sleeve  90  and water treatment device  58 ′ also are removed from water treatment assembly  50 ′. For example,  FIGS. 14-16  shows that sleeve  90  includes resilient members, illustratively snap fingers  91 , and a shoulder  93  to retain cap  98  on sleeve  90 . As shown in  FIG. 16 , a lip  99  of cap  98  is positioned intermediate snap fingers  91  and shoulder  93  of sleeve  90 , and cap  98  contacts shoulder  93  when coupled to sleeve  90 . Cap  98  is axially retained by snap fingers  91  and shoulder  93  but is free to rotate in order to threadedly couple with treatment cavity  84 . Sealing members  102 , illustratively o-rings, may be included to seal treatment cavity  84 . By coupling cap  98  and water treatment device  58 ′ together via sleeve  90 , assembly and serviceability of faucet  10 ′ increases. Additionally, during assembly, cap  98  secures water treatment device  58 ′ within treatment cavity  84 . More particularly, water treatment device  58 ′ may be positioned within treatment cavity  84  and, as cap  98  is threaded onto treatment cavity  84 , cap  98  presses against snap fingers  91  and contacts shoulder  93 . Snap fingers  91  then spring or move outwardly when lip  99  of cap  98  contacts shoulder  93  in order to retain cap  98  on sleeve  90 . As cap  98  is further threaded onto treatment cavity  84 , sleeve  90  and water treatment device  58 ′ are secured within treatment cavity  84  and move inwardly toward first electrically operable valve  60 . 
     Water treatment device  58 ′ illustratively includes first and second channels  118   a  and  118   b,  a pill  59 ′, and electrical wires  92 . Illustratively, first and second channels  118   a,    118   b  are substantially parallel to each other and pill  59 ′ may be intermediate channels  118   a,    118   b.  As shown in  FIGS. 15 and 16 , pill  59 ′ extends in a parallel direction to ribs or dividers  119  on sleeve  90 . Ribs  119  separate the treated water flowing from channels  118   a  and  118   b  for a longer duration in order to increase the concentration of ozone produced in the water flowing from channels  118   a,    118   b.  For example, the ozonated water flowing from channel  118   a  mixes with the water flowing in direction  150 A ( FIG. 4A ) but is separated by ribs  119  from the water flowing from channel  118   b.  As such, ribs  119  may increase the concentration of ozone in the water because the ozone has more time to absorb into the water before the water is mixed and exits treatment cavity  84 , as further detailed herein. 
     Water treatment device  58 ′ is an electrolytic ozone generator configured to produce ozone under pressure; however, water treatment device  58 ′ may be configured to produce ozone through other methods (e.g., corona discharge or “hot spark,” plasma, UV). The illustrative embodiment of water treatment device  58 ′ uses an electric current supplied to wires  92  via external power supply ( FIG. 7 ) and transmitted to pill  59 ′ of water treatment device  58 ′ in order to produce ozone. Exemplary water treatment devices  58 ′ may be available from EOI Electrolytic Ozone Inc. or Klaris Corporation Inc. The current supplied to wires  92  is held constant (e.g., 1.25 amps), however, the voltage may be variable (e.g., 14-24 volts). More particularly, by maintaining a constant current, water treatment device  58 ′ receives a constant power input, thereby allowing water treatment device  58 ′ to consistently operate. For example, when water treatment device  58 ′ produces ozone, the fixed current maintains a consistent output of ozone which increases ozone production and, therefore, increases the concentration of ozone in the water. The voltage is variable and fluctuates to supply water treatment device  58 ′ with necessary voltage depending on the requirements of faucet  10 ′. 
     Controller  136  ( FIG. 7 ) may be configured to determine when the current supplied to water treatment device  58 ′ is not maintained at the constant, predetermined level (e.g., 1.25 amps). Controller  136  is configured to signal the user that water treatment device  58 ′ is not operating efficiently, for example due to mineral build-up, or should be replaced. For example, controller  136  may be configured to flash red and white lights on user input  134  and prevent water treatment device  58 ′ from operating when it is necessary to replace water treatment device  58 ′ and/or when water treatment device  58  is not efficiently producing ozonated or ozone-treated water. If water treatment device  58 ′ is not operating efficiently, controller  136  also may be configured to reverse or flip the current in order to clean water treatment device  58 ′. Additionally, controller  136  also may indicate to a user that water treatment device  58 ′ should be replaced. Exemplary water treatment device  58 ′ may be configured to have a service life of at least approximately two years when typically operating approximately 10 minutes/day. 
     Because water treatment device  58 ′ is positioned under sink deck  5 , sufficient time is permitted for the ozone to be absorbed by the water in second portion  30   b  of outlet tube  30  before the ozone-treated water is delivered from outlet  2 . For example, outlet tube  30  may be approximately  36  inches in length in order to allow the ozone to be sufficiently dissolved or absorbed in the water before reaching outlet  2 . As such, the ozone concentration may increase as water flows toward outlet  2  in second portion  30   b  of outlet tube  30 . Additionally, faucet  10 ′ may include an aspirator (not shown) to facilitate the treatment of the water. 
     When water is configured to flow through water treatment device  58 ′, as shown in  FIG. 13 , water flows in a water passageway  110 ′ which includes valve cavity  76 , treatment cavity  84 , and channels  118   a,    118   b.  Water passageway  110 ′ extends between inlet waterway  64 ′ and outlet waterway  66 ′ and between valve cavity  76  and treatment cavity  84 . Illustrative water passageway  110 ′ has a generally serpentine shape in order to condense water passageway  110 ′. More particularly, water passageway  110 ′ is substantially horizontal through inlet waterway  64 ′ and includes a substantially right-angle bend as water flows in a substantially vertical direction between valve cavity  76  and treatment cavity  84 . Illustratively, water passageway  110 ′ extends between valve cavity  76 , through openings  108  in wall  106 , and into treatment cavity  84 . Water passageway  110 ′ includes another substantially right-angle bend in treatment cavity  84  and extends toward waterway tube  162 . The configuration of water passageway  110 ′ also increases the flow path of the water through water treatment device  58 ′ which may increase the amount of ozone absorbed into the water. 
     As water flows in water passageway  110 ′ between valve cavity  76  and treatment cavity  84 , water is separated such that a portion of the water flows through water treatment device  58 ′ and a portion of the water side streams through channels  118   a,    118   b.  The side streaming water is illustratively denoted by arrows  150 A ( FIG. 4A ) and as such, bypasses water treatment device  58 ′. The side streaming water  150 A may minimize the pressure drop within water treatment housing  54 ′. The water flowing through water treatment device  58 ′ is illustratively denoted by arrows  150 B ( FIG. 4A ) and may be treated, for example with ozone. As shown in  FIG. 4A , arrows  150 A and  150 B indicate that the treated water flowing through water treatment device  58 ′ ( FIG. 13 ) is generally coaxial with the non-treated water flowing around water treatment device  58 ′. As such, when faucet  10 ′ is in the treatment mode, treated and non-treated water simultaneously flow in a generally coaxial arrangement through treatment cavity  84 . Water treatment device  58 ′ is configured to produce ozone (03) from the water flowing in the direction of arrows  150 B (i.e., flowing through water treatment device  58 ′). By separating channels  118   a  and  118   b  with ribs  119  on pill  59 ′, oxygen may be separated from hydrogen from a longer duration of time in treatment cavity  84  and may be better able to form ozone. Therefore, the configuration and structure of pill  59 ′ may increase the concentration of ozone produced by water treatment device  58 ′. 
     Referring to  FIGS. 9, 10, and 12 , water treatment device  58 ′ is fluidly coupled to outlet waterway  66 ′ of water treatment assembly  50 ′ through waterway tube  162 . Outlet waterway  66 ′ also is fluidly coupled to outlet tube  30  and, more particularly, first portion  30   a  of outlet tube  30  is coupled to a first end  66   a ′ of outlet waterway  66 ′ to define a non-treatment flow path  300  ( FIGS. 17A and 17B ) in which the user may control the temperature, flow rate, and other properties of the water via handle  34  and the water flowing to outlet  2  bypasses water treatment device  58 ′. Outlet waterway  66 ′ further includes a second end  66   b ′ which is fluidly coupled to second portion  30   b  of outlet tube  30 . First and second ends  66   a ′ and  66   b ′ may include sealing members  174 , illustratively o-rings, for preventing water leaks between outlet waterway  66 ′ and outlet tube  30 . As shown in  FIGS. 12 and 13 , outlet waterway  66 ′ supports a temperature sensor, illustratively a thermistor  188  and a thermistor retainer  190 . Thermistor  188  is received within an aperture  192  in outlet waterway  66 ′. Illustratively, thermistor  188  is downstream from second electrically operable valve  156  and is configured to electrically communicate with controller  136  in order to determine the temperature of the water. 
     Outlet waterway  66 ′ further includes a third end  66   c ′ which is configured to receive waterway tube  162 . Waterway tube  162  extends between first electrically operable valve  60  and outlet waterway  66 ′. Waterway tube  162  may include sealing members  164 , illustratively o-rings, for preventing water leaks between waterway tube  162  and third end  66   c ′ of outlet waterway  66 ′. Waterway tube  162  is supported by a channel member  166 , which includes a first end  168  adjacent treatment cavity  84  and a second end  170  adjacent third end  66   c ′ of outlet waterway  66 ′. Channel member  166  further includes tabs  172  for assembling or disassembling channel member  166  with waterway tube  162 . 
     Outlet waterway  66 ′ also supports second electrically operable valve  156 . Similar to first electrically operable valve  60 , second electrically operable valve  156  includes a magnetic portion  178 , a plunger  180 , and a valve member  182  having a first side  182   a  comprised of a magnetic material and a second side  182   b  comprised of a non-conductive sealing material, as shown in  FIGS. 12 and 13 . Second electrically operable valve is supported within a valve cavity  184  and is retained therein with fasteners  185 . Second electrically operable valve  156  is configured to move between an open position and a closed position. A spring mechanism (not shown) similar to spring mechanism  275  ( FIG. 11 ) may be included to bias plunger  180  toward valve member  182  such that plunger  180  contacts first side  182   a  of valve member  182 . As such, second electrically operable valve  156  is biased in the closed position. In other words, as shown in  FIG. 13 , second electrically operable valve  156  is closed when no power is supplied thereto and plunger  180  may extend from magnetic portion  178  in order to contact first side  182   a  of valve member  182  and push valve member  182  toward a valve seat  196  ( FIGS. 12 and 13 ). As such, second side  182   b  of valve member  182  is sealingly engaged with valve seat  196  to prevent water from flowing into second portion  30   b  of outlet tube  30 . 
     As shown in  FIG. 12 , in order to open second electrically operable valve  156 , a voltage is applied to magnetic portion  178  to form a magnetic field along plunger  180  when faucet  10 ′ is operating. The magnetic field causes plunger  180  to slide or retract within magnetic portion  178  in order to open or actuate second electrically operable valve  156 . When second electrically operable valve  156  is in the open position, plunger  180  retracts within magnetic portion  178  and compresses spring mechanism  275  ( FIG. 11 ). As such, when second electrically operable valve  156  is operating, plunger  180  is spaced apart from valve member  182 , thereby allowing the water pressure of the water in first end  66   a ′ of outlet waterway  66 ′ to create a pressure differential in valve cavity  184  and push valve member  182  away from valve seat  196  and toward plunger  180  and magnetic portion  178 . As such, water from valve assembly  20  flows through second electrically operable valve  156  and into second portion  30   b  of outlet tube  30 . Water in second portion  30   b  is dispensed from faucet  10 ′ at outlet  2  and is not treated by water treatment device  58 ′. 
     However, when a user desires to dispense treated water, for example ozonated water, from faucet  10 ′, second electrically operable valve  156  is closed and water only flows through first electrically operable valve  60 . When faucet  10 ′ is configured to flow water through water treatment device  58 ′, the ozone-treated water at outlet  2  is preferably used as an antibacterial agent for disinfecting or cleaning applications or purposes. Additionally, the ozone-treated water may be used to disinfect drinking water. More particularly, until the ozone dissolved in the water is destroyed or otherwise destructed, the ozone in the water actively kills or inhibits growth of bacteria in the water. Alternatively, if the ozone dissolved in the water is destroyed, the ozone-treated water remains disinfected or clean, however, the ozone in the water no longer actively kills or inhibits growth of bacteria. 
     Outlet waterway  66 ′ may further include filter  113  ( FIGS. 17A and 17B ). For example, filter  113  may be supported at second end  66   b ′ and downstream from second electrically operable valve  156  and water treatment device  58 ′. Alternatively, filter  113  may be supported in second portion  30   b  of outlet tube  30 . Filter  113  may be configured to further improve the quality of the water by removing impurities or other particles. Additionally, filter  113  may be, for example, a carbon black filter, may be configured to destroy or destruct the ozone in the water in second portion  30   b  of outlet tube  30 . As such, the water in second portion  30   b  of outlet tube  30  is treated with ozone and is disinfected or clean as it is delivered from outlet  2 . However, when the ozone in the water is destroyed by filter  113 , the water delivered from outlet  2  no longer actively disinfects objects in contact with the water. Controller  136  may be operably coupled to filter  113  to control operation of filter  113  and/or the flow of water through filter  113  (i.e., through a bypass valve). As such, a user may selectively operate filter  113  in order to produce disinfected water for particular clean water applications (e.g., drinking) and disinfecting water for other water applications (e.g., cleaning). 
     Faucet  10 ′ may include a quality sensor  144  ( FIG. 7 ) to measure the oxidation-reduction potential (“ORP”) and/or the kill rate of the ozonated water, thereby monitoring the effectiveness of water treatment device  58 ′. For example, under normal operation, faucet  10 ′ is configured to dispense ozonated water having a concentration of at least approximately 0.3 ppm when the water flows at approximately 0.75 gallons/minute and the temperature of the water is approximately 70° or less. Additionally, faucet  10 ′ may be configured to achieve a kill rate of at least approximately 3 log CFU for certain bacteria and viruses within approximately 60 seconds of exposure time on hard surfaces when the flow rate of the water is approximately 0.5-1.0 gallons/minute and the temperature of the water is approximately 70° For less. 
     Referring to  FIGS. 7 and 8 , controller  136  may receive input from sensors, user input  134 , or other inputs to control operation water treatment device  58 ′. Illustratively, user input  134  is a mechanical push button on pedestal  36 . Alternatively, user input  134  may be a touch or proximity sensor implemented by a capacitive sensor, IR sensor, acoustic sensor, and other sensors. Controller  136  electrically controls the operation of water treatment device  58 ′ and may include a timer or clock  142  to tum off water treatment device  58 ′ and/or faucet  10 ′ after a predetermined length of time of operation. For example, controller  136  may be configured to tum off faucet  10 ′ after four consecutive minutes of operation in order to prevent a potential overflow condition in sink basin  1 . Additionally, controller  136  may be configured to tum off water treatment device  58 ′ after three consecutive minutes of operation in order to prevent undesirable off-gassing. Also, clock  142  may record a cumulative amount of time that water treatment device  58 ′ has been operating within a predetermined period. For example, when water treatment device  58 ′ cumulatively operates for approximately 15 minutes during a 60-minute period, clock  142  may send a signal to controller  136 . In response thereto, controller  136  may prevent water treatment device  58 ′ from operating until water treatment device  58 ′ has been inactive for a predetermined time. 
     Additionally, clock  142  may be configured as a water treatment retention timer. More particularly, controller  136  may cooperate with clock  142  to continue operation of water treatment device  58 ′ when a user accidentally bumps or taps spout  12 , thereby accidentally turning off the water. For example, when water flows from outlet  2  and user input  134  is activated, controller  136  activates water treatment device  58 ′ to deliver treated water from outlet  2 . However, if a user accidentally bumps or taps spout  12  while water treatment device  58 ′ is operating, thereby turning off the water, and then subsequently taps spout  12  again within a predetermined time period, the water will tum on and treated water will continue to flow from outlet  2 . As such, controller  136  continues operation of water treatment device  58 ′ for a predetermined time (e.g., 30 seconds) after spout  12  receives a tap to tum water off. If the user does not tap spout  12  within the predetermined time period to tum on the water again, thereby indicating that the user did not accidentally tum off the water, controller  136  will stop operation of water treatment device  58 ′. It may be appreciated that controller  136  may differentiate between a tap on spout  12  for controlling operation of faucet  10  and a grab on spout  12  for adjusting the position of spout  12 . In particular, spout  12  is configured to swivel or rotate and a user may adjust the position of spout  12  without turning on/off the water. 
     Faucet  10 ′ also may include a display or other signal indicator (not shown) operably coupled to user input  134  to indicate to a user whether water treatment device  58 ′ is operating. For example, faucet  10 ′ may include a light-emitting diode (“LED”) display on pedestal  36  that may use a specific color to indicate if water treatment device  58 ′ is active (i.e., turned on). In other illustrative embodiments of the present disclosure, user input  134  may be backlit and illuminates to indicate that water treatment device  58 ′ is operating. For example, user input  134  may be backlit to illuminate a white light when water treatment device  58 ′ is operating. Additionally, user input  134  may include a temperature indicator, for example a blue light for cold water and a red light for hot water. Additionally, user input  134  may be configured to gradually change from red to blue or blue to red to indicate a respective decrease or increase in the temperature of the water, as measured by thermistor  122 . User input  134  also may be configured to produce a flashing light output to signal other conditions of faucet  10 ′. 
     Alternatively, rather than user input  134  to selectively activate water treatment device  58 ′, capacitive sensor  138  and controller  136  may be used to operate water treatment device  58 ′ and/or actuate first electrically operable valve  60  through touch or proximity sensing technology. As such, capacitive sensor  138 , in combination with controller  136 , may be configured to monitor and control the operation of both first electrically operable valve  60  and water treatment device  58 ′. Capacitive sensor  138  may comprise a hands-free proximity sensor, such as an infrared sensor coupled to spout  12 , or a touch sensor to control activation of first electrically operable valve  60  and/or water treatment device  58 ′ in a manner similar to that disclosed in U.S. Patent Application Publication No. 2011/0253220 to Sawaski et al., the disclosure of which is expressly incorporated by reference herein. More particularly, capacitive sensor  138  also may comprise an electrode (not shown) coupled to spout body  12 . The side wall of spout body  12  may be formed of an electrically conductive material (e.g., metal) and define the electrode. In other illustrative embodiments, the electrode may be defined by a separate electrically conductive element, such as a metal plate. Any suitable capacitive sensor  138  may be used, such as a CapSense capacitive sensor available from Cypress Semiconductor Corporation. 
     An output from capacitive sensor  138  is communicated to controller  136 . More particularly, controller  136  may determine whether a touch (tap or grab) is detected on spout body  12  and/or whether a user&#39;s hands or other object are within a detection area proximate spout body  12 . For example, if capacitive sensor  138  is operating with the touch sensor, when a touch is detected on spout body  12 , controller  136  determines the touch pattern (number of touches) before implementing different functions of faucet  10 ′. Controller  136  may determine that a single tap was detected on spout body  12 , thereby indicating that first electrically operable valve  60  should be turned off, for example. Alternatively, controller  136  may determine that two taps (a double tap) were detected on spout body  12  within a predetermined time period (e.g., one second), thereby indicating that first electrically operable valve  60  and water treatment device  58 ′ should be turned on, for example. 
     The concentration of ozone in the water, and therefore, the effectiveness of water treatment device  58 ′, may be affected by parameters or properties of the water, such as flow rate, temperature, the flow mode at outlet  2 , and the amount of power supplied to water treatment device  58 ′. User input  134  may be configured to flash a white light when any of the parameters or properties are insufficient or undesirable for the operation of water treatment device  58 ′. As such, controller  136  monitors and controls the operation of water treatment device  58 ′ in response to signals sent by thermistor  122  and flow rate sensor assembly  124 , power sensor  140 , quality sensor  144 , and mode sensor  120 . The exemplary faucet  10 ′ may be configured for ozone concentrations of at least approximately 0.3 ppm. 
     Power sensor  140  monitors the power available to first electrically operable valve  60 , second electrically operable valve  156 , and water treatment device  58 ′. For example, power sensor  140  may be configured to determine the level of current in water treatment device  58 ′. More particularly, if the current is lower than a predetermined amount, no ozone may be produced by water treatment device  58 ′. As detailed above, a low concentration of ozone decreases the effectiveness of water treatment device  58 ′. Therefore, if water treatment device  58 ′ is turned on when the current supplied to water treatment device  58 ′ is below a predetermined minimum level, controller  136  will prevent water treatment device  58 ′ from operating in order to prevent damage to water treatment device  58 ′. User input  134  may indicate to a user that water treatment device  58  has not been activated. 
     Controller  136  also may communicate with a secondary or back-up power source, illustratively battery  130 , externally coupled to water treatment housing  54 ′ and electrically coupled to first and second electrically operable valve  60  and  156 . If external power supply  146  loses power, faucet  10 ′ may be prevented from operating. However, battery  130  or other secondary power system may provide electricity to faucet  10 ′ in the event of a power loss. Battery  130  is illustratively a qV battery having a service life of at least approximately five years. Battery  130  is configured to power faucet  10 ′ in a non-treatment mode for up to six months in the event of a sustained power loss. User input  134  may be configured to intermittently flash a red light to indicate that battery  130  should be replaced. It may be appreciated that battery  130  can be replaced without accessing water treatment housing  54 ′ because battery  130  is coupled to the outside of water treatment housing  54 ′. 
     Additionally, as shown in  FIG. 11 , thermistor  122  is upstream from water treatment device  58 ′ such that the water flowing from inlet waterway  64 ′ flows over thermistor  122  before flowing to water treatment device  58 ′. The temperature of the water is inversely related to the concentration of ozone in the water, and in particular, as the temperature of the water increases, the concentration of ozone in the water may decrease due to undesirable off-gassing. When controller  136  receives a temperature measurement from thermistor  122  that is greater than a predetermined maximum temperature (e.g., 85° F.) for a predetermined length of time, such that the temperature of the water will adversely affect the concentration of ozone in the water, controller  136  may prevent water treatment device  58 ′ from operating. Additionally, if the temperature of the water is periodically greater than a second predetermined temperature (e.g., approximately 120° F.), undesirable off-gassing also may occur and controller  136  may prevent water treatment device  58 ′ from operating. If water treatment device  58 ′ is activated when the water temperature is equal to or greater than the predetermined maximum temperature, user input  134  may indicate to a user that water treatment device  58 ′ has not been turned on. For example, user input  134  may be illuminated with a flashing white light to indicate that the temperature of the water is not within an operating range for water treatment device  58 ′. 
     Similarly, and as shown in  FIG. 11 , the flow rate of the water may affect the concentration of ozone in the water, and therefore, the effectiveness of water treatment device  58 ′. Illustratively, the predetermined operating range of the flow rate may be approximately 0.01-2.5 gallons/minute. The maximum flow rate may be controlled by pressure-compensating flow restrictor  200  ( FIG. 17A ). Alternatively, as shown in  FIG. 17B , a second flow restrictor  202  may be included in water treatment assembly  50 ′. Illustratively, second flow restrictor  202  is within outlet tube  30  and is intermediate thermistor  122  and second electrically operable valve  156 . When the flow rate of the water is low (e.g., less than approximately 0.25 gallons/minute), undesirable off-gassing may occur. Additionally, when the flow rate of the water is high (e.g., greater than approximately 1.0 gallons/minute), the concentration of the ozone in the water may be adversely affected (i.e., the concentration may be too low), thereby also decreasing the effectiveness of water treatment device  58 ′. User input  134  may be illuminated with a flashing white light to indicate that the flow rate of the water is not within an operating range for water treatment device  58 ′. 
     In certain illustrative embodiments, controller  136  may be operably coupled to flow rate sensor assembly  124  and water treatment device  58 ′ in order to proportionally adjust the ozone output or ozone concentration relative to the flow rate. For example, as the user or flow restrictor  200  decreases the flow of water through faucet  10 , the concentration of ozone may be adjusted because ozone concentration is dependent upon the flow rate. Illustrative faucet  10 ′ is configured to limit airborne ozone caused by off-gassing to approximately 0.05 ppm during an eight-hour time-weighted average, 0.2 ppm during a 15-minute time-weighted average, 10 and 0.5 ppm during peak exposure. 
     The flow modes of the water at outlet  2 , or variations thereof, also may affect the concentration of ozone in the water. More particularly, the turbulence of the water is inversely related to the concentration of ozone in the water. As the turbulence of the water increases, the concentration of ozone in the water may decrease. As detailed above, the stream mode produces a more laminar, less turbulent flow of water at outlet  2  when compared to the spray mode. Additionally, the water is less turbulent when the aerator produces a laminar stream. As such, mode sensor  120  may send a signal to controller  136  to prevent water treatment device  58 ′ from operating when spray head  15  is in a spray mode or when the aerator is in an aerated mode. If water treatment device  58 ′ is turned on when spray head  15  is in the spray mode, for example, controller  136  may prevent water treatment device  58 ′ from operating and user input  134  may indicate to a user that water treatment device  58 ′ has not been activated. Alternatively, controller  136  may send a signal to change the mode of spray head  15  to produce a laminar stream. Additionally, faucet  10 ′ may be configured with a manual override option, thereby allowing users to continue to use faucet  10 ′ in the treatment mode when the water at outlet  2  is turbulent. 
     In alternative embodiments, controller  136  and/or the user may control operation of water treatment device  58 ′ to proportionally increase or decrease the production of ozone relative to the flow rate, the temperature of the water, the current or power supply to water treatment device  58 ′, and/or the properties or composition of the water (e.g., the concentration of ozone outputted to the water may be adjusted if the water has been filtered or otherwise treated before entering water treatment device  58 ′). In particular, pill  59 ′ of water treatment device  58 ′ may be operated by controller  136  to optimize the production of ozone such that the concentration of ozone absorbed into the water also is optimized based upon the detected flow rate and temperature of the water. Additionally, the concentration of ozone in the water may be adjusted to conserve water treatment device  58 ′ (e.g., the output of water treatment device  58 ′ is reduced such that the water may be partially ozonated in order to conserve water treatment device  58 ′). A user input, such as a dial sensor, slide sensor, or other similar inputs may be used to allow the user to positively adjust the concentration of ozone to a particular concentration. 
     As shown in  FIGS. 18A and 18B , the illustrative embodiment faucet  10 ′ may operate according to the following examples. When first and second electrically operable valves  60  and  156  are closed, faucet  10 ′ is off and does not operate (i.e., water does not flow through outlet  2 ), as shown in box  212  and defined as Condition A (box  210 ). When faucet  10 ′ is turned off and in Condition A, water treatment device  58 ′ also is turned off, as shown in box  212 . As shown in box  214 , if the user double touches faucet  10 ′ when faucet  10 ′ is turned off, faucet  10 ′ remains off and does not operate. 
     As shown in box  220 , a single tap may activate second electrically operable valve  156  through capacitive sensor  138  such that second electrically operable valve  156  opens. However, as shown in box  220 , first electrically operable valve  60  remains closed and water treatment device  58 ′ remains turned off. Therefore, non-treated water flows through non-treatment flow path  300  and from outlet  2 . More particularly, faucet  10 ′ may be configured to start in the non-treatment mode, shown in  FIG. 12 , in which water from hot and/or cold water supplies  6 ,  8  flows through second electrically operable valve  156  and valve assembly  20  before flowing from outlet  2 . Faucet  10 ′ may be turned on in the non-treatment mode by activating capacitive sensor  138  by touching or tapping spout  12 , manually moving handle  34 , and/or otherwise activating user input  134  and/or other sensors on faucet  10 ′. The temperature and flow rate of the water may be adjusted by moving handle  34 . If the user adjusts the position of handle  34  to indicate that both hot water and cold water are desired, water flowing from hot water supply  6  flows through hot water inlet tube  26  toward valve assembly  20 . Similarly, water from cold water supply  8  flows into first portion  28   a ′ of cold water inlet tube  28 ′, through T-member  152 , into third portion  28   c ′ of cold water inlet tube  28 ′, and toward valve assembly  20 . Cold water may flow into second portion  28   b ′ of cold water inlet tube  28 ′, however, first electrically operable valve  60  is closed when faucet  10 ′ is in the non-treatment mode and, therefore, water is prevented from flowing into first electrically operable valve  60 . As such, water from cold water supply  8  bypasses first electrically operable valve  60  and water treatment device  58 ′ when faucet  10 ′ is in the non-treatment mode ( FIG. 17A ). When both the hot and cold water flow into valve assembly  20 , the water is mixed in valve body  32  in order to output water at the desired temperature selected by the user through moving handle  34 . The mixed water then flows through first portion  30   a  of outlet tube  30 , through outlet waterway  66 ′, and through second portion  30   b  of outlet tube  30  in order to flow through spout  12  and from outlet  2 . It may be appreciated that when faucet  10 ′ is in the non-treatment mode, first electrically operable valve  60  is closed and water treatment device  58 ′ is not activated. As such and shown in  FIGS. 17A and 17B , both first electrically operable valve  60  and water treatment device  58 ′ are bypassed (i.e., water does not flow therethrough). User input  134  may be illuminated with a blue light to indicate that faucet  10 ′ is operating in the non-treatment mode. As shown in  FIG. 18A , a single tap, as shown in box  228 , may then close second electrically operable valve  156  and return faucet  10 ′ to Condition A (box  230 ) (i.e., faucet  10 ′ is turned off). 
     Referring again to  FIGS. 18A and 18B , a double tap, as shown in box  232 , may activate first electrically operable valve  60  and water treatment device  58 ′, such that the water at outlet  2  is treated with ozone. More particularly, as shown in box  234 , the double touch initiates Condition C, in which second electrically operable valve  156  is closed, first electrically operable valve  60  is opened, and water treatment device  58 ′ is turned on. As shown in  FIG. 13 , when faucet  10 ′ is in the treatment mode shown in Condition C, second electrically operable valve  156  is closed (i.e., valve member  182  is in contact with valve seat  196 ) and, as such, hot water does not flow to spout  12 . Additionally, because second electrically operable valve  156  is closed, any cold water in third portion  28   c ′ of cold water inlet tube  28 ′ does not flow through second electrically operable valve  156  or spout  12 . It may be appreciated that when faucet  10 ′ is in the treatment mode, the operation of faucet  10 ′ is independent of handle  34 . As such, a user may adjust handle  34  without affecting operation of faucet  10 ′ when in the treatment mode. 
     Referring to  FIG. 13 , when in the treatment mode, cold water from cold water supply  8  flows into first portion  28   a ′ of cold water inlet tube  28 ′, through second portion  152   b  of T-member  152 , and into inlet waterway  64 ′ of water treatment assembly  50 ′. First electrically operable valve  60  is opened such that valve member  82  is spaced apart from valve seat  83  to allow water to flow through water passageway  110 ′ and into valve cavity  84 . User input  134  may be illuminated with a white light to indicate that faucet  10 ′ is operating in the treatment mode. 
     As water flows through inlet waterway  64 ′, controller  136  determines, through flow rate sensor assembly  124 , if the flow rate is within an operating range and, likewise, determines, through thermistor  122 , if a temperature of the water is below a predetermined maximum temperature. Additionally, controller  136  determines if the flow mode at outlet  2  defines a stream and if power is available for water treatment device  58 ′. If the flow within the operating range, the temperature of the water is below the predetermined maximum temperature, the flow mode is a stream, and power is available, controller  136  will activate water treatment device  58 ′. As such, and with reference to  FIG. 13 , power is supplied to water treatment device  58 ′, in particular to pill  59 ′. As water flows from valve cavity  76  and into treatment cavity  84 , a side-streaming portion of the water flows in direction  150 A ( FIG. 4A ) around water treatment device  58 ′ and a portion of the water flows in direction  150 B ( FIG. 4A ) through water treatment device  58 ′. When water flows through water treatment device  58 ′, ozone is produced. The ozonated water flows from water treatment device  58 ′ and mixes with the non-ozonated, side-streaming water and flows into waterway tube  162 , through second end  66   b ′ of outlet waterway  66 ′, through second portion  30   b  of outlet tube  30 , through spout  12 , and from outlet  2 . As such, when faucet  10 ′ is in the treatment mode, the water at outlet  2  is treated and may be used for disinfecting purposes. 
     Conversely, if controller  136  determines that the temperature of the water is greater than the predetermined temperature, that the flow rate is above or below the operating range, that the water at outlet  2  is in the spray mode, or that insufficient power is available to water treatment device  58 ′, controller  136  may prevent water treatment device  58 ′ from operating when faucet  10 ′ is in the treatment mode. As such, pill  59 ′ may not be activated and, therefore, ozone may not be produced from the water flowing through channels  118   a,    118   b.  Also, it may be understood that water treatment device  58 ′ will not operate if first electrically operable valve  60  is not operating. User input  134  may indicate that water treatment device  58 ′ is not operating. 
     As shown in  FIG. 18A , only a single touch on spout body  12  (box  240 ) may be required to simultaneously close first electrically operable valve  60  and tum off water treatment device  58 ′. When faucet  10 ′ is in the condition indicated in box  242 , faucet  10 ′ may be completely turned off with a double touch, as shown in box  244 , such that faucet  10 ′ is returned to Condition A (box  246 ). However, controller  136  may continue to detect inputs for a predetermined amount of time (e.g., 30 seconds) in order to determine if the user positively turned off faucet  10 ′ or if the user accidentally tapped faucet  10 ′ without desiring to tum off faucet  10 ′. If the user does not tap faucet  10 ′ after the predetermined amount of time, faucet  10 ′ is returned to Condition A, as shown in box  248 . However, if the user inputs a single touch, rather than a double touch, within the predetermined amount of time, as shown in box  250 , faucet  10 ′ is returned to Condition C (box  252 ). 
     When in Condition C (box  234 ), the user may double touch faucet  10 ′ to open second electrically operable valve  156 , close first electrically operable valve  60 , and tum off water treatment device  58 ′, defined as Condition B (box  260 ). When in Condition B (box  260 ), another double touch by the user, as shown in box  266 , configures faucet  10 ′ in Condition C (box  268 ). Alternatively, if user input  134  is used to selectively indicate that the treatment mode is desired, faucet  10 ′ is configured in Condition C (box  272 ). However, a single touch by the user, as shown in box  262 , configures faucet  10 ′ in Condition A (box  264 ). 
     When in Condition C (box  234 ), the user may activate user input  134 , as shown in box  236 , to return faucet  10 ′ to Condition B (box  238 ). Similarly, when in Condition B in which second electrically operable valve  156  is open, first electrically operable valve  60  is closed, and water treatment device  58 ′ is closed (box  222 ), the user may activate user input  134 , as shown in box  224 , to toggle or switch between the non-treatment mode and the treatment mode and return faucet  10 ′ to Condition C (box  226 ). Also, when in Condition A, the user may activate user input  134  to initiate operation of faucet  10 ′ in the treatment mode. More particularly, when user input  134  is used, as shown in box  216 , and faucet  10 ′ is in Condition A, faucet  10 ′ immediately operates in Condition C to provide treated water at outlet  2 . 
     Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the spirit and scope of the invention as described and defined in the following claims.