Patent Publication Number: US-2020284005-A1

Title: Water Outlet Stagnation and Flush Timing Sensor

Description:
BACKGROUND OF THE INVENTION 
     Stagnant water within pipes and fixtures can lead to leaching and corrosion of materials in contact with the water. Stagnant water can also be a breeding ground for bacteria and pathogens. Children below the age of 6, elderly, and immune-system compromised individuals are more susceptible to water-borne microorganisms and heavy metal contaminants, like lead and copper, which can leach from lead service lines or brass fixtures. Routinely flushing water outlets (i.e. faucets, showers, eyewash stations and fountains) just prior to use can remove these harmful contaminants before using water for drinking or cooking. Flushing before drinking water from outlets is prescribed as a form of contaminant remediation, but there are no methods of confirming whether a water outlet needs flushing or not. This can lead to situations of over-flushing, under-flushing, or simply forgetting to flush altogether, as we must rely on an individual&#39;s judgement and discipline to perform the manual flushing operation. For example, the EPA recommends flushing drinking water outlets for 30 seconds to 2 minutes after stagnation times of 6 hours or more. A problem arises when public water sources are accessed since numerous users may access the water outlet, yet there is no reliable history of the outlet&#39;s recent flushing history. Healthcare facilities (e.g. hospitals, outpatient clinics, surgery centers and nursing homes) often implement flushing protocols to periodically remove stagnant water from plumbing fixtures to prevent the growth and spread of bacteria to staff and patients. Flushing protocols suffer from the inability to confirm whether an outlet has been flushed and for the appropriate amount of time often making it difficult to determine the effectiveness of flushing or meeting flushing compliance. There are currently no known devices for recording water outlet flushing allowing an electronic record to serve as verification of an outlet being flushed. Manual methods of recording flushing are often inadequate and rarely kept as official records of compliance. 
     SUMMARY OF THE INVENTION 
     Embodiments of the inventions described herein include sensor apparatus for determining when a water outlet needs flushing. Water conduits, especially water fountains and related devices, suffer from intermittent usage, and hence some may be little used, and stagnant water may accumulate. The sensor apparatus includes a water flow monitoring sensor adapted to be in contact with a source of water flowing through a conduit; a microprocessor in electronic communication with the water flow monitoring sensor, the microprocessor configured to calculate whether the water stagnation time exceeds a predetermined threshold; and indicia for signaling when the water is in need of flushing by a user, the indicia being in electronic communication with the microprocessor. A further embodiment of the sensor apparatus includes that wherein the water flow monitoring sensor comprises an accelerometer for detecting the vibrations that the inventors have discovered are representative of water usage. 
     Another embodiment of the sensor apparatus includes that wherein the indicia comprises visual indicia such as a colored light source. LEDs are a particularly useful form of indicia. 
     In a further embodiment, the sensor apparatus includes that wherein the accelerometer is located proximate (close to) the terminus (end) of the conduit. The microprocessor is configured to detect the on and off cycles of the water outlet. In a particular embodiment, the microprocessor is configured to determine the stagnation time of the last off time period, compare it to a predetermined threshold of between about one hour to in excess of about twenty-four hours, and if the stagnation time exceeds the threshold, the indicia is set to indicate “flush” to a next user. The microprocessor monitors the flush period, and, if the flush period is in excess of a calculated flush time, the indicia is set to indicate the water is flushed. 
     In a further embodiment the sensor apparatus is rigidly attached to the water outlet, and, in a preferred embodiment, in a non-invasive manner. 
     Yet another embodiment of the invention is a sensor apparatus for determining when a water outlet needs flushing, including an accelerometer in direct contact with a source of water flowing through a conduit, the accelerometer being in communication with a microprocessor configured to track water flow; and indicia for signaling when the water is in need of flushing by a user, the indicia being in electronic communication with the microprocessor configured to calculate whether the water stagnation time exceeds a predetermined threshold. 
     Yet another embodiment of the invention is a sensor apparatus for determining when a water outlet needs flushing, including an accelerometer in direct contact with a source of water flowing through a conduit, the accelerometer being in communication with a microprocessor configured to track water flow; and a light-emitting diode for signaling to a user when the water is in need of flushing by the user, the light-emitting diode being in electronic communication with the microprocessor configured to calculate whether the water stagnation time exceeds a predetermined threshold. 
     Yet another embodiment of the invention is a method for monitoring when a water source is in need of flushing, including the steps of providing a sensor apparatus comprising a water flow monitoring sensor in direct contact with a water conduit, and further comprising indicia for signaling when the water is in need of flushing by a user, the indicia being in electronic communication with a microprocessor configured to calculate whether the water stagnation time exceeds a predetermined threshold; and attaching the sensor apparatus to a water source capable of being monitored in a non-invasive manner. 
     Yet another embodiment of the invention is a sensor network for monitoring when one or more water sources have been flushed, comprising a plurality of water flow monitoring sensors attached to separate water conduits; one or more nodes capable of connecting to each water flow monitoring sensor when necessary to communicate water data; one or more servers configured to communicate, store, access and process water data from the network; communications infrastructure connecting the water flow monitoring sensors, nodes, servers and users; and flushing indicia for signaling to a user when the water is in need of flushing by a user, the flushing indicia being available to a user in need of the information for determining whether the water stagnation time exceeds a predetermined threshold. 
     Another embodiment of the invention specifies that the communications infrastructure includes the internet. 
     Another embodiment of the sensor network is that wherein the flushing indicia comprises a database of records indicating the flushing history of any sensor connected to a node. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a computer-generated elevational perspective view of an embodiment of the present invention. 
         FIG. 2  is an exploded version of  FIG. 1  along the x-axis. 
         FIG. 3  is a computer-generated pictorial view of the current embodiment installed on the terminal portion of a faucet located on the apron of a standard sink. 
         FIG. 4  depicts an elevational view of a block diagram of the present invention. 
         FIG. 5  is an electronic schematic of the PCB specifically showing the interconnections between the microprocessor  3  and the motion sensor/accelerometer  4 . 
         FIG. 6  is a front elevational top perspective of an exploded view of another embodiment of the sensor. 
         FIG. 7  is a front, elevational bottom perspective of an exploded view of another embodiment of the sensor. 
         FIG. 8  is a front elevational perspective view of an assembled version of another embodiment of the sensor. 
     
    
    
       
     
       
         
           
               
               
             
               
                   
               
               
                 Part No. 
                 Description 
               
               
                   
               
             
            
               
                  1 
                 Printed Circuit Board (“PCB”) 
               
               
                  2 
                 Battery 
               
               
                  3 
                 Microprocessor 
               
               
                  4 
                 Motion sensor/Accelerometer 
               
               
                  5 
                 Power regulator 
               
               
                  6 
                 Red LED 
               
               
                   6a 
                 Red LED 
               
               
                   6b 
                 Green LED 
               
               
                  7 
                 Timing clock 
               
               
                  8 
                 Timing information 
               
               
                  9 
                 Chip select 
               
               
                 10 
                 In port 
               
               
                 11 
                 Out port 
               
               
                 12 
                 Interrupt 
               
               
                 13 
                 First memory element 
               
               
                 14 
                 Temporary memory element 
               
               
                 15 
                 Logic element 
               
               
                 20 
                 Battery Door 
               
               
                 22 
                 Sensor Body 
               
               
                 24 
                 First Clip 
               
               
                 25 
                 Battery connector 
               
               
                 26 
                 Second Clip 
               
               
                 30 
                 Water flow monitoring sensor 
               
               
                 50 
                 Cover 
               
               
                 51 
                 Anchor 
               
               
                 52 
                 Anchor 
               
               
                 60 
                 Base 
               
               
                 61 
                 Tab 
               
               
                 62 
                 Tab 
               
               
                 63 
                 Projection 
               
               
                 64 
                 Projection 
               
               
                 65 
                 Battery Holder 
               
               
                 66 
                 O-ring 
               
               
                 67 
                 Clip 
               
               
                 68 
                 Clip 
               
               
                 70 
                 Electronics package 
               
               
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION OF THE INVENTION 
     The inventions described in preferred embodiments in the following detailed description are with reference to the various numbered figures, in which like numbers represent the same or similar elements. Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
     The described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are recited to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. 
     The embodiments of the inventions described herein propose a novel apparatus and method by use of an electronic timed lighting system and a water flow monitoring sensor affixed to a water outlet. By utilizing a sensor to identify water flow through a water outlet a timer can be activated in for example a microprocessor. When an amount of time has passed since the water last flowed, the microprocessor can activate a lighting device to notify the user the water outlet needs to be flushed before the water is safe to consume. Once the sensor identifies that water has started running through the outlet the microprocessor can initiate a second timer to monitor the duration of time the outlet is flushed. Once an acceptable amount of time has elapsed since the start of the water flow, the microprocessor can then deactivate the lighting system thereby notifying the user that the water is now safe to consume. This timing element would consider premature “stops” during the flushing process, resetting itself if the sensor detects that the flow of water stopped before adequate flushing time was achieved, thus ensuring that the user knows to continue flushing the water outlet before consuming the water. 
     An embodiment of the invention is directed to sensor apparatus for determining when a water outlet needs flushing, comprising a water flow monitoring sensor in direct contact with a source of water flowing through a conduit; and indicia for signaling when the water is in need of flushing by a user, the indicia being in electronic communication with a microprocessor configured to calculate whether the water stagnation time exceeds a predetermined threshold. 
     One embodiment of a sensor that can be used is an accelerometer. An accelerometer is a device that measures proper acceleration. Accelerometers have been miniaturized and embedded in silicon for many years and have become ubiquitous in cell phones, video game consoles, inertial detection systems, automobiles, and innumerable devices that require detecting a change in position. A list of all of the applications of miniaturized accelerometers is beyond the scope of this text, and the list of types of accelerometers is long: Bulk micromachined capacitive, Bulk micromachined piezoelectric resistive, Capacitive spring mass system base, DC response, Electromechanical servo (Servo Force Balance), High gravity, High temperature, Laser accelerometer, Low frequency, Magnetic induction, Modally tuned impact hammers, Null-balance, Optical, Pendulous integrating gyroscopic accelerometer (PIGA), Piezoelectric accelerometer, Quantum (Rubidium atom cloud, laser cooled), Resonance, Seat pad accelerometers, Shear mode accelerometer, Strain gauge, Surface acoustic wave (SAW), Surface micromachined capacitive (MEMS), Thermal (submicrometre CMOS process), Triaxial, Vacuum diode with flexible anode, potentiometric type and lastly LVDT type. One or more of the previous listed accelerometer types may be used in the current embodiment of the invention, however a preferred type of sensor that can measure these vibrations is a MEMS (Micro Electrical Mechanical Sensor) accelerometer, which works by having a known mass suspended inside of an integrated circuit by small beams. Consistent with Newton&#39;s second law of motion (F=ma), as an acceleration is applied to the device, a force develops which displaces the mass. In this embodiment, the kinetic energy released through the normal operation of a water tap or faucet creates a vibration, or movement, which is then transferred to the accelerometer due to the close physical contact of the sensor and the water source, creating a measurable acceleration in one or more axis. 
     The measured acceleration is then converted to an analog signal and compared to a predefined threshold of 144 mg, compared to the reference point of the acceleration of gravity (1 g=9.8 m/s 2 . Once the sensed kinetic energy surpasses this threshold the accelerometer sends a signal to the microprocessor notifying it that an event consistent with activation of the water outlet has occurred. The microprocessor can then begin monitoring the data from the accelerometer, begin a timer, and activate and deactivate a notification light. A suitable MEMS accelerometer is obtainable from ST Microelectronics Inc. as Part No. LIS2DH12. 
     Another aspect of the present embodiment involves indicia for signaling when the water is in need of flushing by a user. Preferably the indicia is a visual indicia, although other alerting means may be used such as audible indicia for example, to alert those with a visual impairment. The preferred indicia is a visual one such as a light. Taking advantage of the known warning function of the color red, a red light may be used to indicate when the water is in need of being flushed. Light-emitting diodes may be used to great effect in the current embodiments as means to indicate that the water source under consideration is in need of being flushed because the standard time for residence of the water in a conduit as determined by the United States Environmental Protection Agency (“EPA”) has been exceeded. In the current embodiment, a red LED is used to indicate if the system needs flushing (continuously on), or hasn&#39;t been flushed enough (flashing on). If the LED is not lit, this can indicate that there is no need for flushing (water has been flushed recently and is safe). In another embodiment a green LED may be used in combination with a red LED to further indicate various flushing states of the water. For example, a green LED when continuously lit may indicate the water has been flushed recently for an adequate time period. 
     In an embodiment utilizing an accelerometer the sensor may be located proximate the source of the vibration, which occurs when the water is turned on. In most instances, this location is at or close to where the tap, valve or faucet handle is located. For the accelerometer to pick up the strongest vibrations caused by the opening of a tap or valve, it should be closely located. Another reason is that the user should be within visual distance of the LED when about to operate the tap or valve so that a user can interpret what if any flushing action needs to be taken prior to use of the water faucet. 
     The accelerometer embodiment may be configured to detect the on and off cycles of a water source by detecting the vibrations specific to the actuation of a tap, valve or handle. It is well-known that when a water source is turned on, the pressurized water transmits some of its kinetic energy to the walls of the conduit thereby causing vibrations that can be detected by the accelerometer and associated circuitry. This is known as the “water hammer” effect. When turned off, the vibrations cease. Therefore, the turning on and off of a water supply generates vibrations which can be detected by an accelerometer and used to mark the cycles of running versus stagnant water in the conduit. 
     In the current embodiment the microprocessor is configured to determine the stagnation time of the last off time period, compare it to a predetermined threshold of between about one hour to in excess of about twenty-four hours, and if the stagnation time exceeds the threshold, the indicia is set to indicate “flush” to a next user. The “flush” indicia as currently employed is a blinking red LED, or a solid red LED. The only difference being that a solid red LED indicates that flushing is in progress until the flush timer setting has been achieved and the light turns off. The flashing red LED is used to conserve power and extend battery life rather than consuming unnecessary power by keeping a solid red LED. 
     A further embodiment of the previous apparatus is that wherein a microprocessor monitors the flush period, and, if the flush period is in excess of a preset flush time, the indicia is set to indicate the water is safe. Flushing before drinking water from outlets is prescribed as a form of contaminant remediation. As previously described, the EPA recommends flushing drinking water outlets for 30 seconds to 2 minutes after stagnation times of 6 hours or more. Flush times can be linked to stagnation times using hard-coded look-up table values or user programmable times allowing water outlets that have remained stagnant for too long to be flushed for longer times. This method allows users to “flush on demand” and control flushing times to save water. It provides for more effective implementation of flushing protocols by eliminating the guess work around whether a water outlet has been recently flushed or needs flushing. It reduces the likelihood of over-flushing, which saves water, and under-flushing, which could leave unhealthy levels of contaminants in the next release of water. 
     By utilizing a sensor to identify water flow through a water outlet a timer can be activated within a microprocessor. When an amount of time has passed since the water last flowed, the microprocessor can activate the red LED to notify the user the water outlet needs to be flushed before the water is safe to consume. Once the sensor identifies that water has started running through the outlet the microprocessor can initiate a second timer to monitor the duration of time the outlet is flushed. Once an acceptable amount of time has elapsed since the start of the water flow, the microprocessor can then deactivate the LED notifying the user that the water is now safe to consume. This timing element would consider premature “stops” during the flushing process, resetting itself if the sensor detects that the flow of water stopped before adequate flushing time was achieved, thus ensuring that the user knows to continue flushing the water outlet before consuming the water. If the flush time was not long enough, the LED will return to its pre-flushing mode, which means it may blink at a predetermined frequency, or it may go back to solid. 
       FIG. 1  is a computer-generated elevational perspective view of an embodiment of the present invention, water flow monitoring sensor  30 . Red LED  6  is shown on one face of the sensor body  22  but it actually is mounted on PCB  1  and protrudes through an opening in body  22  (not shown). Battery door  20  is shown in the closed position and only the top of the door is shown. Clips  24  and  26  may be molded into sensor body  22  and function to engage with a water conduit (shown in  FIG. 3 ) by expanding slightly as they are pressed against a round conduit, then snapping back as they engage the conduit so that the sensor body is rigidly affixed to the conduit so that maximal transmission of vibrations may occur between the conduit and the sensor body. 
       FIG. 2  is an exploded version of  FIG. 1  along the x-axis. Battery  2 , PCB  1 , water flow monitoring sensor  30  and battery door  20  are shown. Battery  2  slideably engages the battery connectors  25  to make positive power connection with PCB  1 . PCB  1  comprises a number of elements described further in  FIGS. 4-5  including LED  6 , microprocessor  3  and sensor/accelerometer  4 . PCB  1  fits into the back side of water flow monitoring sensor  30  and door  20  will slidably engage water flow monitoring sensor  30  to provide a means of access so that a battery may be changed out when necessary. 
       FIG. 3  is a computer-generated pictorial view of a first embodiment of the water flow monitoring sensor  30  installed on the terminal portion of a faucet located on the apron of a standard sink. Note that the LED faces the user so that it may visually indicate the status of the water while the user is actuating either of the tap handles. 
       FIG. 4  depicts an elevational view of a block diagram embodiment of the present invention. Printed circuit board (“PCB”)  1  provides an electronic scaffold with interconnections (not shown) for discrete components microprocessor  3 , motion sensor/accelerometer  4 , power regulator  5  and LED  6 . The source of power may be a battery  2  shown connected in this view to the PCB from a position below the PCB. The electronic interconnections are of a standard nature well-known to one of ordinary skill in the art. Battery connectors  25  are customary metallic positive and negative spring-like connectors. In this embodiment accelerometer  4  and the visual indicia/LED  6  are co-located, however they may be separated spatially if necessary. In the embodiment wherein they are separated, a near-field electronic connection such as Bluetooth may be employed to allow the accelerometer to communicate to the visual indicia. 
       FIG. 5  is an electronic schematic of the PCB specifically showing the interconnections between the microprocessor  3  and the motion sensor/accelerometer  4 . 
     Microprocessor  3  comprises a timing circuit/clock, one or more registers for counting the passage of time, and an arithmetic logic unit for performing various calculations supporting the tracking of flushing and stagnation times of the system. One embodiment of the invention may utilize a 32-bit MCU ARM Cortex microprocessor, available from Digikey, Thief River Falls, Minn., PN STM32L011F3. One of ordinary skill may select various capacities and types of memory suitable to the job, but it is understood that various forms of on-board memory such as EEPROM or flash memory are conventionally integrated into the microprocessor package. 
     PCB  1  has dedicated lines for the Timing Clock, Chip Select, Serial Ports In and Out, and Interrupt. In this embodiment, motion sensor/accelerometer  4  is a discrete component of the PCB that is in electronic communication with microprocessor  3 . 
     Power regulator  5  receives power from battery  2  and converts it to 1.8V, then making it available via power bus on PCB  1 . Alternatively, power regulator  5  may convert to a higher voltage up to about 5 V if necessary to drive additional LEDs. 
     Motion sensor/accelerometer  4  is configured to send an interrupt signal  12  to the microprocessor  3  for the purpose of waking it from deep sleep mode. Typically the motion sensor is awakened by the turning on of a faucet, which creates a large vibration detected by the accelerometer. Motion sensor/accelerometer  4  is capable of continuous communication via a serial port, com port, SPI, I2C, or similar communication protocol with microprocessor  3 . Motion sensor/accelerometer  4  is capable of receiving timing information  8  from microprocessor  3 . Microprocessor  3  employs a timing clock  7  for the purpose of accurately tracking a multiplicity of time segments. The timers available consist of externally monitored timers (such as timing the duration of an external source, e.g. counting the number of clock cycles that a monitored pin has been in a high state), a system tick timer (used to track the number of milliseconds that a task has been performed), and a watchdog timer (used to activate the microcontroller after a certain number of system ticks). These timers are all managed independently of the system memory, though they do access the memory to identify start and stop parameters. Timing clock  7  is employed to track a first segment of time (non-flow time). This would be an example of a system tick timer. Non-flow time is the period of time that may result in a determination of a stagnant water status if the non-flow time exceeds, e.g., 6 hours. Timing clock  7  is next employed to track a second segment of time (flow time). This would be an example of an externally monitored timer. Flow time is simply that, the amount of time measured while water is flowing and thus exiting the conduit. Flowing water has a vibrational signature that is detectable by the accelerometer. In order to meet EPA requirements, flow time must exceed the 30 second minimum threshold in any 6 hour period for the water status to be determined safe to consume. Timing clock  7  may be employed to track a third segment of time (extended non-flow time). Extended non-flow time is any cumulative non-flow time in excess of 6 hours. The cumulative amount of extended non-flow time may determine the flush time. For example, in one embodiment any extended non-flow time greater than 6 hours but less than 12 hours may determine a flush time of 30 seconds is required. For extended non-flow time of greater than 12 hours a flush of 1 minute may be required. For extended non-flow time of greater than 24 hours a flush of 2 minutes may be required. Timing clock  7  may also be employed to track a fourth segment of time (flow reset time). Flow reset time is the minimum amount of flushing activity that will reset the status from “needs flushing” to “safe”. In one embodiment this is a minimum threshold of 15 seconds of continuous flushing during any 6-hour period. Any continuous flushing less than that will not reset the sensor. 
     Another embodiment of the timing sequence used in a water flow monitoring sensor may result in different trigger times for flushing. For example, the discussion above where the minimum time for a flush is 6 hours may be reset to 128 hours for a medical facility that is concerned with water-borne bacterial infection tracking since, unlike lead- and copper-leaching, bacteria require on the order of days or weeks to multiply enough to become a health hazard. These trigger times may be pre-set at the time of purchase, or may be reconfigured during use. They may also be remotely reconfigurable by software update. This would be an example of a watchdog timer. 
     Another embodiment of the water flow monitoring sensor is adapted to track the water usage of a specific conduit, or a group of water conduits. Water usage is determined from start/stop timestamps to determine duration of flow and time of usage throughout the day. Flow rate may also be calculated given the amplitude of vibrations and the diameter of the conduit providing the water. Calibration of a water flow monitoring sensor can be done by physically measuring the amount of flow from the faucet being monitored over a specific time, which measurement can then be recorded in a look-up table available to the sensor or a remote processor programmed to do the calculation in the cloud. Then, flow rate x duration of the flow measured by the water flow monitoring sensor will give the volume of water used. 
     In an embodiment motion sensor/accelerometer  4  is configured to filter out the steady state acceleration due to the earths&#39; gravity. It then measures the acceleration of the device in all three spatial axis and sends an interrupt signal to the microcontroller when the measured acceleration on any axis exceeds a preset threshold for a specific period of time. In an embodiment, the acceleration threshold is set to 144 mg and the period is set to 240 ms. These values can be adjusted as needed to improve device sensitivity to vibration and to exclude detection of unwanted vibrations. 
     The timers on the device keep track of the amount of time since the last triggered interrupt from the accelerometer. As outlined above, at varying thresholds of elapsed time, the timers change the behavior of the one or more LEDs in order to indicate to the user that the water has been running or stagnant for the specified amount of time. In an embodiment the timers keep track of four periods of stagnant water, and the timers have three periods to indicate a proper flush time based on the amount of stagnant time. In an embodiment the resolution of each timer tick is 1 second. These timer periods can also be adjusted for future iterations. 
     In an embodiment the sensor apparatus is mounted to a water conduit in a non-invasive manner. Non-invasive means that the sensor is not in direct contact with the water, but is mounted externally, that is, on the exterior of a pipe, hose, tube or similar water flow conduit. This ensures the sensor does not create an opportunity to contaminate the water, or create another point of failure in the conduit. 
       FIG. 8  is a front elevational view of another embodiment of the invention, and  FIGS. 6 and 7  are front elevational top and bottom perspectives, respectively, of the exploded views of this embodiment. This sensor embodiment has the same basic electronics package as the previous embodiment plus telecommunications capabilities, but the packaging is different. Generally, in alternate embodiments numerous packages can be designed for different applications, with the primary functional criteria being that contact between the attachment portion of the water flow monitoring sensor and the electronics be maintained so that the accelerometer can detect the vibrations sufficiently to distinguish the water flow pattern from extraneous environmental vibrations. Cover  50  and base  60  are the two primary external housing components for housing the electronics package  70 . In an embodiment cover  50  is a translucent cover having two attachment elements  51 / 61  and  52 / 62  for attaching base  60  to cover  50 . Anchors  51  and  52  located on the opposite ends of cover  50  are substantially identical receivers for tabs  61 ,  62  similarly located on opposite ends of base  60  into which they engage by projections  63 ,  64  fitting through and clicking into place via the receiving slots in anchors  51  and  52 . 
     Electronics package  70  includes PCB  1 , battery  2  and battery holder  65 . In this embodiment, PCB  1  is mounted on battery holder  65  which is of standard design and includes positive and negative terminals for connecting the battery with the PCB thereby supplying the PCB with electrical power. Electronics package  70  fits inside the base and cover so that when the two are snapped together, they are sealed from the environment by o-ring  66 . Clips  67 ,  68  are similar in design to clips  24 ,  26 . The overall dimensions of this embodiment are approximately 2″×1″×1.5″ (L/W/D). 
     In the embodiment of  FIGS. 6-8  there are two LEDS depicted as  6   a  and  6   b  on PCB  1 , one green and one red. The LEDs could be selected from other combinations of colors too. Since the electronics package  70  is mounted within cover  50  and the LEDs are oriented to face the cover, the lit LEDs are visible to anyone from the outside. In an embodiment, the pattern of their lighting indicates the following information to a viewer: 
     
       
         
           
               
               
               
             
               
                   
               
               
                 Red LED 
                 Green LED 
                 Status 
               
               
                   
               
             
            
               
                 On 
                 Off 
                 Flushing in process 
               
               
                 Blinking 
                 Off 
                 In need of flushing 
               
               
                 Off 
                 Blinking 
                 No flushing needed - safe to drink 
               
               
                 Off 
                 Off 
                 Battery Dead/System error 
               
               
                 3 quick flashes 
                 Off 
                 Low battery - replace 
               
               
                 Off 
                 3 quick flashes 
                 New battery installed - OK 
               
               
                   
               
            
           
         
       
     
     The electronics package  70  may additionally include IoT-type telecommunications capabilities and an on-board memory sufficient to save a number of days&#39; worth of sensor activity. The SEMTECH SX1276 Long Range Transceiver is one such candidate from the SEMTECH LoRa® platform for wireless RF long-range, low-power IoT solutions. In an embodiment, 2 MB of on-board memory is sufficient to store the data. However, the specific application will dictate the amount of memory. The on-board memory will enable the sensor unit to gather data that will show a number of use activities of the system, including but not limited to the average stagnation time, the average time between flushes, the volume of water being consumed at this faucet and associated high and low values. The data will include but is not limited to timestamps, and potentially geolocation. When combined with timestamped data, water outlet usage information can also be generated to determine patient or staff exposure to an outlet or to provide evidence of hand-hygiene/washing compliance. Both approaches rely on the ability to sense and store data to identify when water is flowing and not flowing from an outlet. 
     Embodiments may also download stored data via a hard connection such as a LAN/Ethernet/USB or other standard hard-wire connection type that are well-known to persons having ordinary skill in the electronics and telecommunications arts. 
     Another embodiment of the invention comprises a sensor network for monitoring when one or more water sources have been flushed, comprising a plurality of water flow monitoring sensors attached to separate water conduits. The sensor network includes one or more communication nodes capable of connecting to each water source flush sensor when necessary to communicate water data. The sensor network may also include one or more servers configured to communicate, store, access and process water data to and from the nodes and users. The sensor network may also include communications infrastructure connecting the water source flush sensors, nodes, servers and users. A typical infrastructure may be the internet, but may also be a private intranet, a WAN/LAN/LPWAN or other well-known communications system. The sensor network may also include flushing indicia for signaling to a user when the water is in need of flushing by a user, the flushing indicia being available to a user in need of the information for determining whether the water stagnation time exceeds a predetermined threshold. Such indicia could be local to the water flow monitoring sensor itself such as the LED(s) of prior embodiments, or could also be remote databases or remotely-monitored dashboards having apps displaying the indicia. A user would merely have to access the dashboard or remote app to learn of the flush or usage status of any specific monitored point in the sensor network. 
     An embodiment includes one or more water flow monitoring sensors connected to a datalogger, or alternatively embedded within a Wireless Sensor Network (WSN) allowing for upload of water use data from various locations, and under various use circumstances, thereby allowing pattern analysis of water flushing and water use wherever the water flow monitoring sensor is located. The WSN is built of “nodes”—from a few to several hundreds or even thousands, where each node is connected to one (or sometimes several) sensors. Each such sensor network node has typically several parts: a radio transceiver with an internal antenna or connection to an external antenna, a microcontroller, an electronic circuit for interfacing with the sensors and an energy source, usually a battery or an embedded form of energy harvesting. Dataloggers are an older version of a node, and are usually located in extreme and/or remote locales where servicing is on an annual basis or even less frequent. Nodes are typically connected, or connect intermittently, to a gateway device that is then in communication with a LAN/WAN/Low-power WAN system for connection to the internet or private network where a server may store the water data. 
     As is well-known to those of skill in the telecommunications arts, there are several wireless standards and solutions for sensor node connectivity. Thread and ZigBee can connect sensors operating at 2.4 GHz with a data rate of 250 kb/s. Many use a lower frequency to increase radio range (typically 1 km), for example Z-wave operates at 915 MHz and in the European Union 868 MHz has been widely used but these have a lower data rate (typically 50 kb/s). The IEEE 802.15.4 working group provides a standard for low power device connectivity and commonly sensors and smart meters use one of these standards for connectivity. With the emergence of the so-called “Internet of Things,” many other proposals have been made to provide sensor connectivity. LORA is a form of LPWAN which provides long range low power wireless connectivity for devices, which has been used in smart meters. Wi-SUN connects devices at home. NarrowBand IOT and LTE-M can connect up to millions of sensors and devices using cellular technology. And finally, various BLUETOOTH standards exist for short-range low-power applications that may be installed in a water flow monitoring sensor and allow it to connect to a short-range BLUETOOTH-compatible node. 
     Energy/power consumption of the sensing device should be minimized and sensor nodes should be energy efficient since their limited energy resource determines their lifetime. To conserve power, wireless sensor nodes normally power off both the radio transmitter and the radio receiver when not in use. The sensor wireless communications function can be programmed to turn on (“wake up”), connect to their node and download data for any given period, then power off (“sleep mode”) until the next reporting interval has passed. 
     In other embodiments the flush timing sensor may facilitate online collaborative sensor data management platforms, which are on-line database services that allow sensor owners to register and connect their devices to feed data into an online database for storage and also allow developers to connect to the database and build their own applications based on that data. Examples include Xively and the Wikisensing platform. Services include allowing developers to embed real-time graphs and widgets in websites; analyze and process historical data pulled from the data feeds; send real-time alerts from any datastream to control scripts, devices and environments. 
     Various applications of the embodiments described herein include a wireless water sensor data management system fed data by a network of “smart” water sources (taps, faucets, basins etc.) in one or more buildings such as, for example, a medical campus that can be accessed to track the history of water use at each source thereby allowing for hospital acquired infection monitoring. 
     Additional embodiments of the invention described herein include the sensor unit integrated into any original equipment fixtures, such as a sink-mounted or water fountain faucet, a showerhead, an appliance-based dispenser such as a refrigerator-installed water dispenser or icemaker. The primary design consideration for such installations is to ensure the sensor and water source are in sufficient contact so that the vibrations from the water source pipe is reliably detectable by the sensor circuitry. In a refrigerator having a water dispenser, typically there is also a filter. The sensor unit could track the on time of the dispenser, correlate the on time to total water flow through the unit, and give a warning to indicate when it is time to replace the filter based on actual use, not elapsed time as is the current practice.