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TECHNICAL FIELD 
     This invention is in the field of grey water usage for flushing toilets. 
     BACKGROUND ART 
     It is estimated that the average American residence uses in the range of 100,000 gallons of water annually and that more water is used to flush toilets than showering or any other individual activity (Reference: Indoor Water Use in the United States, US EPA, June 2008, EPA-832-F-06-004). Grey water is defined as lightly used or unprocessed water which can be re-applied, in this case, to the flushing of toilets. Currently, almost all grey water is disposed of right after leaving the source fixture (e.g. a wash basin) or appliance (e.g. a washing machine). Numerous grey water toilet systems have been proposed in order to conserve water. 
     One type of system serves an entire building and utilizes a common reservoir where grey water is collected from the sinks, showers, bath tubs, washing machines, rain collection points, appliances etc. The stored grey water is then utilized by grey water applications such as toilets. This type of system requires extensive design and integration and is costly to retrofit into existing buildings. Examples of these systems include U.S. Pat. No. 4,115,879, 1978 Toms; U.S. Pat. No. 4,197,597, 1980 Toms; U.S. Pat. No. 4,162,218, 1979 McCormick; U.S. Pat. No. 5,345,625, 1994 Diemand; U.S. Pat. No. 5,452,956, 1995 Gilliam; U.S. Pat. No. 5,496,468, 1996 Cormier; U.S. Pat. No. 5,498,330, 1996 Delle Cave; U.S. Pat. No. 5,573,677, 1996 Dembrosky; U.S. Pat. No. 5,845,346, 1998 Johnson; U.S. Pat. No. 6,328,882, 2001 Rosenblatt; U.S. Pat. No. 6,702,942, 2004 Nield; U.S. Pat. No. 6,796,250, 2004 Greene; U.S. Pat. No. 6,889,395, 2005 Hodges; 6904926, 2005 Aylward et al.; 7121292, 2006 Aylward et al.; 8974663, 2015 Aylward et al.; 7913331, 2011 Hartman; U.S. Pat. No. 8,696,897, 2014 Marugame; U.S. Pat. No. 5,084,920, 1992 Kimball. 
     Less expansive grey water toilet systems include connected sink/toilet combinations,  FIG. 1  (examples include U.S. Pat. No. 4,358,864, 1982 Medrano; U.S. Pat. No. 6,276,005, 2001 Sanders et al.; 6802090, 2004 Martin; and U.S. Pat. No. 8,931,122, 2015 Cerce) as well as integrated sink/toilet fixtures,  FIG. 2 ,  FIG. 3  (examples include U.S. Pat. No. 5,813,047, 1998 Teichroeb and U.S. Pat. No. 9,057,186, 2015 Augustine). However, even these simpler grey water toilet systems require a significant investment to install into existing bathrooms due to the need for remodeling the bathroom area. Often, replacement or repositioning of the existing fixtures is necessary. In addition, some of these systems require electrical access to power the pump  11  used to pressurize or move the grey water from a storage reservoir  12  to the toilet  10  (examples include U.S. Pat. No. 5,201,082, 1993 Rockwell; U.S. Pat. No. 5,317,766, 1994 McDonald et al.; 5937455, 1999 Donati; and U.S. Pat. No. 0,059,755, 2014 Garrels et al.). The various costs associated with the installation of a grey water toilet such as remodeling, outage time, and inconvenience, are deterrents to the adoption of these systems. 
     Foot operated devices have been applied for different individual toilet functions in the past. Foot pedals have been used to trigger the flush operation of toilets for many years. Examples include U.S. Pat. No. 1,585,557, 1924 Miller; U.S. Pat. No. 1,864,827, 1931 Jenkins et al.; 2467019, 1944 Farson; U.S. Pat. No. 3,594,828, 1971 Seek; U.S. Pat. No. 3,594,829, 1971 Seek; U.S. Pat. No. 3,883,904, 1975 Wittman; U.S. Pat. No. 5,142,708 1992 Johnson et al.; U.S. Pat. No. 8,286,273 B1, 2012 Toomer; and D6492335, 2011 Du, as well as Chinese patents: CN202370063U, 2012 and CN203222872U, 2013. These devices attach to the existing flush mechanisms of toilets and apply a small amount of energy from a user&#39;s foot action to trigger a flush event, providing more hygienic touch free flushing. Foot powered pumps have also been proposed to provide flush water for portable toilets. An example is U.S. Pat. No. 5,398,465, 1995 Tagg. Foot powered pumps and water transfer mechanisms for flushing toilets have been proposed by several Chinese patents: CN2166167Y, 1994; CN2355010Y, 1999; CN2407051Y, 2000; CN2496938Y, 2002; CN2639383Y, 2004; CN2742053Y, 2005; and CN103726543A, 2014. However, these foot powered water transfer devices are not designed to integrate with existing toilets and require custom installation or remodeling. Some are standalone components and do not offer a complete solution. For example, many of these designs require installation of a custom toilet versus integrating with an existing toilet. A practical grey water toilet retrofit system should handle all the functions related to flushing a toilet with simple input from the user. These functions include: triggering the flush mechanism, resupplying the toilet tank with grey water and handling situations when there is either too much or too little grey water. The use of grey water in toilets has not been commercially viable or widely available in part due to the high cost to retrofit existing toilets with a practical system. The goal of this invention is to overcome these obstacles. 
     SUMMARY OF INVENTION 
     Technical Problem 
     Toilets commonly employ a cistern, otherwise known as a toilet tank  20 , to hold a volume of water which is released during a flush cycle. The toilet tank is typically filled from the building&#39;s fresh water supply plumbing. This invention proposes a method,  FIG. 6 , along with a system,  FIG. 4 , to retrofit existing toilets to utilize grey water instead of fresh water. It aims to provide a user installable, ergonomic system, through a combination of new and prior art to: collect grey water from existing bathroom fixtures; store a supply of grey water until needed; trigger the toilet&#39;s native flush mechanism; move the grey water to the toilet tank at the appropriate point in time; and resolve situations when grey water is either lacking or overabundant. 
     Typical residential bathrooms have a toilet with a wash basin nearby. However, most existing wash basins are positioned too low to allow the resultant grey water to flow directly into most existing toilet tanks. Thus, current grey water toilet systems either require the wash basin drain to be raised higher than the toilet tank level or require a powered pump  11  to move the grey water from a storage reservoir  12  up to the level of the toilet tank  13 . Many of these systems necessitate remodeling to position the fixtures appropriately or to provide an electrical source for the required pumping mechanism. 
     Typically, toilet tanks  60  are at a level of approximately 0.305 to 0.610 meters (1 to 2 feet) above the bathroom floor. Thus the grey water held in the temporary storage reservoir  61 , positioned near the bathroom floor level,  FIG. 8 , must be moved up in elevation to fill a toilet tank. For example, many current toilets in the United States utilize 6.06 liters (1.60 gallons) per flush. Therefore an embodiment of a grey water toilet retrofit system must be capable of lifting at least 6.06 liters up in elevation of approximately 0.610 meter (2 feet). 
     The energy E w  required to lift grey water of weight w an elevation rise d is represented in  FIG. 9  and shown by the equation EQ1:
 
 E   w   =w×d   EQ1:
 
     To supply the same amount of energy, E f , with a foot pedal, a force F on the pedal for a travel distance h is required. This is represented in  FIG. 7  and shown by the equation EQ2:
 
 E   f   =F×h   EQ2:
 
     Combining these two equations result in the unified equation EQ identifying the force F required on the foot pedal to move the grey water from the reservoir to the toilet tank under ideal conditions:
 
 F =( w×d )/ h   EQ:
 
     Ergonomically it would be beneficial to minimize both the required pedal force F,  FIG. 7  as well as pedal travel distance h,  FIG. 7 . From EQ, we see that decreasing the required elevation raise d,  FIG. 9  as well as decreasing the volume of grey water w,  FIG. 9  support these goals. 
     For example, since the weight of 6.06 L (1.60 gallons) of water is 6.06 kg, a force of 59.3 N is required to lift this weight. From EQ1, the energy required to move 6.06 L of grey water up 0.610 m is 36.2 Joules (59.3 N×0.610 m). From EQ2, this is equivalent to pressing down on a pedal with a force of 36.2 N for 1 m or equivalently 119 N for 0.305 m. If however, the grey water held in the reservoir can be positioned above the floor level, less pedal force will be necessary. For example, if it is possible to install the grey water reservoir elevated to 0.305 m (1 ft) above floor level, then only 18.1 J of energy or 59.3 N of force for 0.305 m is needed to lift the grey water up to the toilet tank. This is half of the energy and force on the pedal needed to move the grey water up to the toilet tank as compared to the 0.610 m elevation rise scenario. Thus it is beneficial to mount the reservoir as high as possible but still low enough to collect grey water from the various sources. 
     Although a small amount of additional force is necessary to overcome parasitic losses and to trigger the toilet flush mechanism, we see from these examples that a force of approximately 59.3 N to 119 N (13.3 to 26.7 pound-force) and a pedal movement of 0.305 m (1 ft) is sufficient to move the amount of grey water needed for a single flush in a typical contemporary toilet in the US today. Since there is a wide variation of toilet tank and wash basin design, the necessary elevation rise and thus pedal force required will vary with each setup. In addition, many older toilets require more water to flush and thus a greater grey water capacity from embodiments of this invention. 
     From this discussion, we see that it is possible for the average person to impart enough energy with a single foot pedal actuation to lift the necessary amount of liquid to resupply a toilet tank. 
     System timing,  FIG. 5 , is another factor in creating a practical human powered grey water retrofit system. Two areas related to timing need to be considered: timing when the foot pedal can be released after the actuation stroke; and timing when the main volume of the grey water is transferred into the toilet tank relative to the flush cycle, which varies based on the specific toilet system design. 
     Ergonomically, it is preferable that the user does not have to worry about timing at all. Thus the foot pedal should be allowed to be released at any time after the actuation stroke so that the user does not have to hold the pedal down waiting for the flush cycle to complete or progress to a certain point. 
     Timing when the main volume of grey water is sent to the toilet tank varies with the many toilet designs and flush cycles being used. Ideally, the main volume of grey water should be introduced into the toilet tank when the current flush cycle progresses to the point where the grey water is able to supply the toilet tank for the next flush cycle. Introducing grey water too early can result in the grey water flowing out prematurely with the current flush cycle. In some installations, the inherent delay in moving the grey water into the toilet tank provides sufficient time to prevent this. In other installations, an additional explicit delay is also needed. 
     Other considerations include: how to handle situations when either too much or too little grey water is available as well as how to trigger the toilet&#39;s flush mechanism as an integral part of an embodiment. 
     A solution to these problems without the need for significant remodeling or the need for electrical power will help grey water usage for flushing toilets become more broadly accepted thereby achieving greater water conservation. 
     Solution to Problem 
     As demonstrated by one or more of the embodiments described here, this invention relates to methods and devices that utilize grey water for the flushing of toilets. Grey water  24  is collected  50  in a holding reservoir  25  in advance of a flush operation. A pedal  21  mechanism begins receiving energy  51  from the user. This energy is stored  52  by an energy storage mechanism  26  as it is received. A toilet flush is triggered  53  directly when the pedal is actuated  57  or indirectly through the energy storage mechanism  26  after sufficient energy is available  56 . Receiving energy from the pedal  51 , triggering the toilet flush  53  and storing the pedal energy  52  can overlap in time and occur simultaneously. A delay  55 , comprising intrinsic and optionally explicit portions, defers the grey water introduction into the toilet tank. The explicit delay component  28  allows the current flush to progress before the transfer mechanism  27  moves  54  the grey water  24  from a holding reservoir  25  into the toilet tank  20 . The grey water from the holding reservoir  25  can also supplement the current flush cycle as well as supply the toilet tank  20  for the next flush cycle. 
     The amount of energy required to move the grey water depends on both the amount of grey water required and the elevation rise d,  FIG. 9  from the holding reservoir to a toilet tank. For example, from equation EQ, we see that 36.2 Joules of energy is required to move 6.06 liters (1.6 gallons) of grey water up an elevation of 0.610 meter (2 feet). A pedal operated mechanism will be able to provide this energy by applying 119 N (26.7 lb.-force) over a pedal travel distance of 0.305 m (1 ft.). 
     Triggering the flush cycle for typical toilets require minimal pressure on the toilet&#39;s flush mechanism. For example, 8.90 to 22.2 N (2 to 5 lbs. of force) over 2.54 to 5.08 cm (1 to 2 inches) or in the range of 1 Joule of energy will normally be sufficient to trigger a mechanical toilet flush. 
     Typical embodiments of this system comprise: a reservoir  25  for collecting grey water  24  in advance of a toilet flush; a pedal  21  for receiving human mechanical energy from a user&#39;s foot  23  actuation; an energy storage mechanism  26 , for example, such as a spring or weight or pneumatics to hold the imparted human energy allowing the pedal to be released immediately after the foot actuation; a flush trigger actuator link  22  and flush adaptor  32  to trigger the toilet&#39;s native flush mechanism  31 ; a manual powered liquid transfer mechanism  27  or pump to transfer the grey water  24  to the toilet tank  20 ; and a grey water outlet  29  connecting the reservoir with the toilet tank. An explicit delay mechanism  28  can be included to control the point in time when the grey water enters the toilet tank if needed for a particular installation. 
     The liquid storage reservoir  25  stores the grey water  24  which can originate from various sources. Ideally, this reservoir is positioned lower than the grey water source  30  so that grey water can naturally flow into it utilizing gravity, without the need for mechanical assistance. Typically, this grey water storage reservoir  25  is positioned near floor level, below the exit pipes of nearby fixtures which supply the grey water but as high as possible to minimize the energy required to move the stored grey water to the toilet tank. 
     The pedal  21  operated mechanism is utilized by the user to start a flush cycle. When pressure is applied by the user&#39;s foot  23 , a mechanical link  22  actuates the flush adaptor  32  connected to the toilet&#39;s flush mechanism  31  initiating a normal flush cycle. Continued foot pressure provides energy to transfer the grey water in the holding reservoir  25  up to the toilet tank  20  resupplying the toilet tank in preparation for the next flush cycle. While it is desirable to utilize a single pedal stroke per flush cycle, multiple strokes may be applied to decrease pedal effort or shorten stroke distance or provide additional energy which can be stored for future flush cycles. 
     The energy storage mechanism  26  holds the energy from the user&#39;s pedal actuation, thus allowing the pedal to be released immediately. This energy storage mechanism can utilize an explicit component, such as for example a spring, or alternatively can be realized without an explicit component, for example by imparting potential energy to the grey water by elevating it. For single pedal stroke operation, the energy storage capacity should hold enough energy to operate a single flush cycle. However, larger energy storage capacities can also be utilized to store energy for additional flush cycles. 
     Since the time it takes to complete a flush cycle varies with different toilets, it is beneficial in some installations to delay the transfer of grey water into the toilet tank so that it does not all flow out to the toilet bowl during the current flush cycle. This can occur if the grey water is introduced into the toilet tank too early during the flush cycle. 
     Timing diagram  FIG. 5  shows the flush and fill cycles of a retrofitted grey water toilet as reference. Small parasitic delays in timing are not represented. The exact timing varies based on different toilet designs and installations. The flush cycle begins when a user depresses the foot pedal at time  40  and triggers the toilet&#39;s native flush mechanism. At this point, the flush valve is opened and the previously stored water in the toilet tank begins to flow into the toilet bowl. At the same time, energy from the pedal actuation is stored, allowing the flushing process to continue even as the pedal is released at time  41 . The grey water fill process is delayed for time interval  45  until the current flush cycle progresses to time  42 , the point at which the grey water is able to supply the toilet tank for the next flush cycle, preventing all of the grey water from flowing out prematurely with the current flush cycle. The delay duration  45  is comprised of an implicit system delay due to the grey water flow rate and grey water distance traveled from the reservoir to toilet tank as well as an optional explicit delay needed for some toilet setups. This optional explicit delay may not be needed in cases where the implicit delay is sufficient. For example, this may be the case for toilets with high flush flow rates where a large flush valve closes quickly after a flush cycle is triggered. 
     If needed, the explicit delay duration can be determined through monitoring one of the toilet&#39;s operating parameters such as the liquid level in the toilet tank, pressure level in the toilet tank, flow rate out of the toilet tank and flush valve position. Alternatively, a fixed timer based on timing from prior flush cycles, can also be applied.  FIG. 18  through  FIG. 20  are examples of valves that can be utilized to provide the appropriate explicit delay by sensing the surrounding liquid level in the toilet tank and allowing the grey water to enter when the level reaches a predetermined point. 
     The toilet tank&#39;s flush valve begins to close near time  42 . This point is near the end of the flushing process at time  43  when the water level in the toilet tank is at or near its low water mark. The toilet tank&#39;s native fill system is left intact ensuring that enough water is provided to the toilet tank for the next flush cycle in case there is insufficient grey water available. This native fill system introduces fresh water at a relatively slow rate as compared to the flushing rate of water exiting to the toilet during the flush interval, see  FIG. 5 , and continues to fill the toilet tank with fresh water from the beginning of the flushing interval at time  40  to the end of the fill process at time  44 . To maximize the fresh water savings, embodiments can introduce grey water at a sufficiently high rate to fill the toilet tank, before significant fresh water is introduced by the native fill system. 
     Additional fresh water savings can be achieved by modifying the native fresh water fill system to include a delay or by decreasing the fresh water input flow rate. This allows more grey water to fill the toilet tank and thus requiring less fresh water. Partially closing the fresh water supply valve  33  into the toilet tank is one way to achieve a fresh water flow rate reduction. Any excessive grey water introduced to the toilet tank is automatically expelled by the toilet tank&#39;s native overflow system. 
     Advantageous Effects of Invention 
     This human powered system allows more efficient usage of water resources by enabling existing bathrooms to be retrofitted to use grey water for the flushing of toilets. Existing wash basins and toilets can be integrated with this grey water flush system with minimal or no remodeling and without the need to add an electrical source to power the system. 
     A pedal  21  interface makes this system ergonomically easy to use and accessible to most users. This pedal performs key functions including triggering the toilet&#39;s flush mechanism  31  and providing energy to supply the toilet tank  20  with grey water  24  for the next flush. 
     Automated functions provide consistent operation allowing the user to release the pedal  21  at any time without concern about the system timing or grey water availability. An energy storage mechanism  26  holds the energy received from the pedal  21  allowing the pedal  21  to be released immediately after actuation. If needed, an optional explicit delay  28  of the grey water to the toilet tank allows enough time for the flush cycle to progress, preventing most of the grey water from flowing out to the toilet bowl with the current flush cycle. 
     The toilet&#39;s existing fresh water fill mechanism is utilized to supplement the grey water should the supply of grey water be temporarily unavailable or inadequate. For example, this may happen if multiple flushes are performed before sufficient grey water is collected in the liquid storage reservoir. Excessive grey water is expelled, utilizing the toilet tank&#39;s existing overflow mechanism should too much grey water be introduced into the toilet tank, preventing an overflow situation. These features combine to provide ease of use as well as backup redundancy. If this grey water retrofit system fails, the toilet can continue to operate as it would before the retrofit by utilizing its native flush and fresh water fill capabilities. 
     Although, this system is focused towards retrofitting existing toilet installations, it can also be applied to new toilet installations. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  Grey water toilet system utilizing electric pump—Prior Art 
         FIG. 2  Grey water toilet system with wash basin as toilet tank cover—Prior Art 
         FIG. 3  Grey water toilet system with unified wash basin and toilet tank—Prior Art 
         FIG. 4  Human powered grey water toilet retrofit system, concept view 
         FIG. 5  Timing diagram, retrofitted grey water toilet flush and fill system 
         FIG. 6  Flow chart, retrofitted grey water toilet flush and fill system 
         FIG. 7  Energy E f  from foot pedal as a function of force and stroke distance 
         FIG. 8  Reservoir collecting grey water from wash basin prior to flush 
         FIG. 9  Energy E w  needed to transfer grey water from reservoir to toilet tank 
         FIG. 10  Human powered grey water toilet retrofit system, example 1 embodiment 
         FIG. 11A  Pressure based transfer and energy storage mechanism in trigger/transfer phase, embodiment 
         FIG. 11B  Pressure based transfer and energy storage mechanism in refill phase, embodiment 
         FIG. 11C  Pressure based transfer and energy storage mechanism in ready phase, embodiment 
         FIG. 12A  Elevation based transfer and energy storage mechanism in trigger/transfer phase, embodiment 
         FIG. 12B  Elevation based transfer and energy storage mechanism in refill phase, embodiment 
         FIG. 12C  Elevation based transfer and energy storage mechanism in ready phase, embodiment 
         FIG. 13  Handle pull flush trigger adapter, conceptualized drawing 
         FIG. 14  Button press flush trigger adapter, conceptualized drawing 
         FIG. 15  Internal actuated flush trigger adapter, conceptualized drawing 
         FIG. 16  Grey water extraction adapter embodiment 
         FIG. 17A-D  Toilet tank fill adapter embodiment, without valve 
         FIG. 18A  Liquid level sensing valve embodiment, closed position 
         FIG. 18B  Liquid level sensing valve embodiment, closed position, cutout view 
         FIG. 18C  Liquid level sensing valve embodiment, open position 
         FIG. 18D  Liquid level sensing valve embodiment, open position, cutout view 
         FIG. 19A-D  Toilet tank fill adapter with liquid level sensing valve, embodiment 
         FIG. 20A  Liquid level sensing valve horizontal embodiment, closed position 
         FIG. 20B  Liquid level sensing valve horizontal embodiment, open position 
         FIG. 20C  Liquid level sensing valve horizontal embodiment, exploded view 
         FIG. 21  Grey water toilet tank fill adapter, cover entry embodiment 
         FIG. 22  Grey water toilet tank fill adapter with level sensing valve, cover entry embodiment 
         FIG. 23  Grey water toilet tank fill adapter, tank entry embodiment 
         FIG. 24  Grey water toilet tank fill adapter with level sensing valve, tank entry embodiment 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     As demonstrated by one or more of the embodiments, this invention relates to devices that utilize grey water for the flushing toilets. Central to the invention is the method and system to utilize human power to trigger a toilet flush cycle and re-supply the toilet tank with grey water for the next flush cycle. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention comprises of a combination of pre-existing as well as new components and is not limited in its application to the details of construction and to the arrangements of the devices and components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting. There are many alternate forms of the described embodiments. Any suitable device, component, size, shape, position or type of materials can be used to implement this invention. 
     The following are example embodiments covering the different components making up this system, see  FIG. 4 . The functions performed by this system may be combined and embodied in numerous ways. Modules can perform individual functions or, alternatively, multiple functions can be implemented together in the same module as in the following examples. 
     Example 1: Pressure Based Grey Water Toilet Retrofit System and Method 
     This embodiment applies pressure directly to the grey water in order to force it out of the reservoir and into a toilet tank. In this example, the reservoir  71 , pedal  77 , energy storage  83 , flush actuator link  74  and pump/liquid transfer mechanisms  90  are unified, decreasing the overall footprint of the system. While numerous mechanisms can be devised to pressurize the grey water,  FIGS. 10, 11A, 11B and 11C  are depictions of one embodiment based on a pedal operated mechanism during the three phases of operation:  FIG. 11A , trigger/transfer;  FIG. 11B , refill; and  FIG. 11C , ready. This embodiment utilizes a direct pressure design applying principles of a hybrid diaphragm/displacement pump. This pump/liquid transfer mechanism is integrated with the grey water reservoir  71 . The top of the reservoir incorporates a diaphragmed plunger  72  in contact with the grey water  73 . Note that any alternate pump design, such as for example a piston and cylinder (not shown), which can move approximately 6.06 liters (1.6 gallons) of water up an elevation of approximately 0.610 meters (2 feet) utilizing approximately 36.2 Joules can also be applied in this example. 
     The trigger/transfer stage  FIG. 11A  is initiated when the user depresses the pedal  77 . Energy is received  51  from this pedal and applied  57  to triggering a toilet flush  53 , by actuating the flush linkage  74 , as well as stored  52  by compressing a spring  83 . The compressed spring transfers this energy by applying pressure to the plunger  72 . This plunger  72  in turn applies pressure to the grey water  73  in the reservoir  71  forcing it out  87  of the exit  88  and transferring  54  it to the toilet tank. An outlet check valve  80  at the reservoir exit  88  is used to prevent the backflow of water from the toilet back into the reservoir. An inlet check valve  81  at the reservoir entrance  82  prevents grey water from leaving the reservoir inlet during this phase. The spring  83  and catch  84  mechanism work together in order to store the energy so that continued pressure is applied to the grey water by the plunger even after the user releases the pedal  77 . As the grey water empties from the reservoir, the spring  83  reaches its extended position and the catch mechanism releases  85 , relaxing the plunger and advancing the embodiment to the refill phase  FIG. 11B . 
     In the refill phase,  FIG. 11B , grey water enters through the inlet check valve  81  mounted in the entrance port  82  near the top of the reservoir. A vent valve  86  allows any air to rise and escape as grey water enters the reservoir. The float in this valve automatically closes as the grey water level rises filling the reservoir. In this phase, grey water is collected  50  in the reservoir over time as it becomes available from various sources, such as wash basins, filling it in preparation for the next flush cycle. 
     Once the reservoir is filled, the embodiment is in the ready phase  FIG. 11C  of operation awaiting the next toilet flush. Although the pedal  77  can be depressed at any time, during any state of fill, only the amount of grey water  73  in the reservoir  71  at the time of the pedal actuation will be transferred to toilet tank. If there is not enough grey water to refill the entire toilet tank, the toilet&#39;s native automatic fill system will continue to refill the toilet tank as it would normally. If, on the other hand, too much grey water is sent to the toilet tank, the excess amount will be automatically discharged by the toilet tank&#39;s normal overflow system. 
     A flush trigger adapter  32  is utilized to trigger the native flush mechanism of a toilet as part of this grey water toilet system.  FIG. 13 ,  FIG. 14  and  FIG. 15  are conceptualized drawings of example flush trigger adapters which can be driven by the pedal mechanism to start a flush cycle. These sample embodiments simulate a user&#39;s action of triggering a toilet flush by depressing the toilet&#39;s flush lever, see  FIG. 13 , or button, see  FIG. 14 , or actuating the toilet&#39;s flush mechanism internally, see  FIG. 15 . A small amount of force, substantially equivalent to what is required to manually trigger a toilet flush, is needed for the flush trigger adapter to trigger the toilet&#39;s flush mechanism. New or pre-existing adapter designs can be used as part of this grey water toilet system. 
     Electronic flush systems can also be remotely triggered by the foot pedal. Example designs include an electronic flush adapter connected to the internal flush electronics of the system or physically simulating the user&#39;s input (not shown). 
     Grey water needs to be routed into the toilet tank as part of this grey water toilet system. A custom fill adapter  76  can be utilized for this purpose.  FIG. 17A  through  FIG. 17D  show an embodiment of one such grey water fill adapter. This embodiment allows existing toilet tanks to be retrofitted so that grey water is introduced without the need for modifications to the toilet or remodeling of the room in many situations. The toilet&#39;s pre-existing functionality such as its native water fill capability and flushing capability are retained. Installation is achieved by lifting the toilet tank cover, fitting this adapter over the edge of the toilet tank and repositioning the original toilet tank cover on top of the adapter along with spacers  130  as needed. Grey water is delivered into the toilet tank with this adapter through a gap  131  between the toilet tank and its cover. A large cross sectional area  132 ,  133  maximizes the rate grey water can flow into the toilet tank. 
     This custom fill adaptor embodiment consists of a grey water entry port positioned outside of the toilet tank with a manifold body which channels the grey water to a contoured grey water exit port  134  inside the toilet tank. The manifold body  135  is designed to wrap over the upper edge of the toilet tank. This manifold body is positioned between the toilet tank and the toilet tank cover. Spacers  130  can be utilized to stabilize the toilet tank cover on top of the assembled adapter and toilet tank. Different variations of this embodiment (not shown) allow grey water to enter the toilet tank from different positions depending on the available clearance and specific layout needs within the room. 
     Alternatives to utilizing a custom grey water fill adapter include creating a grey water entrance hole/port directly in the toilet tank cover  FIG. 21  and  FIG. 22  or directly on the toilet tank,  FIG. 23  and  FIG. 24 . 
     Grey water for this toilet system can come from any source. Typically, wash basins  78  can be tapped for grey water using standard drain pipe components (not shown) as well as utilizing a custom grey water extraction adapter  79 ,  FIG. 16 . In any case, the grey water extraction adapter should divert grey water from the normal drainage path to the storage reservoir. When the storage reservoir is filled to capacity with grey water, additional grey water automatically flows out through the normal drainage path  120 . 
     An embodiment of a level sensing, high flow rate valve that can be applied to provide an explicit delay  55  to the sudden entry of fluid into the toilet tank is shown in  FIG. 18A  through  FIG. 18D . This explicit delay device  28  is needed in some installations where the inherent system delay is insufficient for preventing the grey water from being expelled with the current flush cycle. Desirable characteristics include: an on/off state based on the surrounding liquid level; an abrupt high flow capacity, since water is sent to the valve only during a flush; a compact form factor to fit into as many toilet tanks as possible; a low actuating force to allow smaller actuating components; and a simple low maintenance design. This embodiment uses two housings  140  and  141  with exit openings  142 ,  143  that align  FIG. 18C  and  FIG. 18D  to allow liquid flow. A seepage gap  144  between the housings allows liquid flow which essentially removes friction between the housings, enabling free movement. A float  145  follows the liquid level in the surrounding environment  146  moving the outer housing  141 , aligning the exit openings  142  and  143  to open the valve and offsetting the exit openings  142  and  143  to close the valve. The exit openings are designed and positioned so that the flow of liquid is orthogonal to and symmetric around the actuation axis  147  resulting in net force cancellation from the flow, thus substantially decreasing the required on/off state actuation force. The low actuation force requirements in this embodiment, allow for smaller float dimensions to operate this valve. However, this very low on/off state actuation force may also result in the valve opening inadvertently when the float is mid transition between the valve&#39;s off and on states. To prevent premature opening of the valve, the exit openings are positioned such as to direct the liquid seepage flow  148  to hold the outer housing  141  up, in the valve&#39;s closed position, until the float is low enough to force this outer housing  141  down, opening the valve. This seepage flow also moderates the shock effect of abrupt flow changes. Open and close levels are calibrated with the open limit adjuster  150  and close limit adjuster  149 . Gasses can also flow through this seepage gap  144  providing a venting capability through the valve. 
     A horizontal embodiment,  FIG. 20A  through  FIG. 20C , of a level sensing high flow rate valve is also possible and useful for certain toilet tank configurations where a vertical embodiment will not physically fit into a toilet tank. This embodiment use two housings  170  and  171  with exit openings  172 ,  173  that align,  FIG. 20B , to allow liquid flow. A seepage gap (not shown) between the housings allows liquid flow which essentially removes friction between the housings enabling free movement. A float  175  follows the liquid level in the surrounding environment rotating the outer housing  171 , aligning the exit openings  172  and  173  to open the valve and offsetting the exit openings  172  and  173  to close the valve. The exit openings are designed and positioned so that the flow of liquid is orthogonal to and symmetric around the actuation axis  177  resulting in net force cancellation from the flow, thus substantially decreasing the required on/off state actuation force. The low actuation force in this embodiment, allows for smaller float dimensions to operate this valve. However, this low on/off state actuation force may also result in the valve opening inadvertently when the float is mid transition between the valve&#39;s off and on states. To prevent premature opening of the valve, the exit openings are positioned such as to direct liquid seepage flow  178  to hold the housings in the closed position until the float is low enough rotate the outer housing  171  to open the valve. This seepage flow also moderates the shock effect with abrupt flow changes. The valve&#39;s close level is calibrated with a limit adjuster  180 . The valve&#39;s open level is calibrated by rotating the entire valve assembly. Gasses can also flow through the seepage gap providing a venting capability through the valve. A locking ring  181  fits over a locking grove  182  holding the entire valve together. 
     Example 2: Elevation Based Grey Water Toilet Retrofit System and Method 
     This embodiment replaces the reservoir, pedal, energy storage, flush actuator link and liquid transfer mechanisms of the first example with an elevation based mechanism. Numerous mechanisms can be utilized to raise the grey water high enough so that it will naturally flow into the toilet tank using gravity. These include displacing the grey water upward within the storage reservoir as well as physically raising the reservoir above the level of the water entrance to the toilet tank as in this embodiment.  FIGS. 12A, 12B and 12C , are conceptual depictions of a mechanical embodiment which utilizes a series of pulleys  100  to multiply the pedal  101  motion in order to raise the storage reservoir  102  high enough for the grey water  103  to flow to the toilet tank. In this embodiment, the kinetic energy received from the pedal is converted to and stored as potential energy when the reservoir is raised. The number of pulleys determines the ratio of pedal movement to reservoir lift distance. In this embodiment, the pulley system multiplies the pedal movement of distance h,  FIG. 12C  by three times as represented by 3×h in  FIG. 12A . The three phases of operation are:  FIG. 12A , trigger/transfer;  FIG. 12B , refill; and  FIG. 12C , ready. A counter weight in the pedal offsets the weight of the empty reservoir to minimize the actuation energy required on the pedal. Flexible hoses allow the storage reservoir to move up transferring the grey water to the toilet tank. 
     The trigger/transfer stage  FIG. 12A  is initiated when the user depresses the pedal  101 . Energy is received  51  from this pedal, applied  57  to triggering a toilet flush  53 , by actuating the flush linkage  104 , and then stored in potential form  52  by a series of pulleys  100  lifting the reservoir  102  up in elevation. The reservoir is raised high enough for the grey water to flow  54  into the toilet tank using gravity. An outlet check valve  105  at the reservoir exit  107  is used to prevent the backflow of water from the toilet back into the reservoir  102 . An inlet check valve  106  at the reservoir entrance prevents grey water from leaving the reservoir inlet  108  during this phase. A vent valve  110  opens to allow air in as the grey water level drops. A catch mechanism  109  holds the reservoir in the upper position effectively storing the potential energy, so that grey water continues to flow even after the user releases the pedal  101 . When the grey water becomes depleted from the reservoir, the catch mechanism releases  111 , allowing the reservoir to descend and the embodiment to advance to the refill phase,  FIG. 12B . 
     In the refill phase,  FIG. 12B , grey water enters through the inlet check valve  106  mounted in the entrance port  108  near the top of the reservoir. A vent valve  110  allows any air to rise and escape as grey water enters the reservoir. The float in this vent valve automatically closes as the grey water level rises filling the reservoir. In this phase, grey water is collected  50  in the reservoir over time as it become available from various sources, such as wash basins, filling it in preparation for the next flush cycle. 
     Once the reservoir  102  is filled, it is in the ready phase,  FIG. 12C , of operation awaiting the next toilet flush. Although the pedal  101  can be depressed at any time, during any state of fill, only the amount of grey water  103  in the reservoir  102  at the time of the pedal actuation will be transferred to toilet tank. If there is not enough grey water to refill the entire toilet tank, the toilet&#39;s native automatic fill system will continue to refill the toilet tank as it would normally. If, on the other hand, too much grey water is sent to the toilet tank, the excess amount will be automatically discharged by the toilet tank&#39;s normal overflow system. 
     With respect to the above descriptions then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in components, size, materials, shape, form, function and manner of operation, assembly and use, are deemed to be within the expertise of those skilled in the art, and all equivalent structural variations and relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. Therefore, the foregoing is considered as illustrative only be resorted to, falling within the scope of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Summary:
A grey water toilet system utilizing a pedal interface to trigger the toilet flush and to resupply the toilet tank with grey water. The grey water is generally collected from a nearby water fixture such as a wash basin and placed in a storage reservoir until the user flushes the toilet. This invention can be used to retrofit most existing toilets without the need for remodeling thus making it possible to expand the use of grey water for toilets, potentially leading the way for significant fresh water savings. It is estimated that the average American residence uses in the range of 100,000 gallons of water annually and that more water is used to flush toilets than any other individual activity.