Save Water! Kitchen Faucet With Foot Pedal




Clean water is more valuable than most of us realize. Clean water requires energy, so by conserving water, you're also conserving energy! You can help minimize its waste by installing a foot pedal to control your kitchen sink. We're going to install a couple of solenoid valves under your sink, and wire them up to a simple pedal. It's easier than you think, and you don't need any plumbing or electrical experience to do it. So, let's get started!

(If you like this Instructable, please vote for it! If you don't like it, please vote for it anyway leave feedback below so I can make it even better.)

Step 1: Parts: the Solenoids

The heart of this project is a solenoid valve. Very simply, these are small bits of pipe that have a valve that will open or close when you apply electricity to them. I picked these up on eBay for about $15/ea (here's a search link to help).

Solenoid valves have a few important attributes:

  • the type of voltage required to activate them
  • whether they're open or closed when they're unpowered, and
  • the size or flow rate they will support.

For this project, we're going to want a pair of 12V DC, normally closed valves that will support about 3 GPM (gallons per minute). Typically, the larger diameter of the "pipe", the larger the flow rate. I went with 1/2" solenoid valves, and they're more than adequate for this project.

Step 2: Parts: the Plumbing Bits

Some of this is going to depend on what size solenoid valves you go with, and what size fixtures you have under your sink. My fixtures were 3/8" (which I believe is standard), and my solenoid valve was 1/2" inch with male connectors on each end, so I needed adapters to go from 1/2" male to 3/8" male, and 1/2" male to 3/8" female. Your local home parts or plumbing store should carry these. Don't be afraid to ask for help, and if you already have your solenoid valves, bring one along to help avoid confusion. You will need one of each for each solenoid valve, so four adapters in total.

If you use a connector like the one in the first picture and your solenoid valve is plastic, you might want to try to find a 1/2" rubber washer, as going from brass to plastic can leak unless it's very tight. The adapter in the second picture has built-in rubber seals.

Step 3: Parts: the Electrical Bits

In order to activate the solenoids to let the water flow through them, we're going to need some sort of switch or pedal. Again, I went to eBay and found this one for about $9. If you have the talent, it wouldn't take much effort to make up your own pedal, but for this project I decided to go with a pre-made pedal.

You're also going to need some wire. I had some spare speaker wire sitting around, and it was perfect for this project. I used about 12' of it, but that gave me plenty of slack to reposition the pedal.

Finally, you're going to need a power source. For this Instructable I used a pair of battery holders (one that holds 2 AA batteries, and one that holds a 9v battery (giving us 12V)). You can find these at Radio Shack or Fry's, or a similar store. You can also use a 12V DC adapter (a.k.a. "wall wart") if you'd prefer. The instructions will be the same, regardless, but if you use a 12V adapter, make sure you have a GFCI outlet installed.

Step 4: Tools and Accessories

As far as tools go, you will need either a wrench (5/8" or 16mm, or adjustable) or some pliers. A pair of wire strippers will be handy as well, but there's very little wiring to do, so you can probably strip the wires with a knife.

To make this Instructable as accessible as possible, I have done all of my electrical connections by twisting the wire and wrapping with electrical tape. If you have the means, I would recommend soldering the connections, but I wanted to show that it wasn't necessary.

You will also want a bowl to catch the small amount of water that will come out when we disconnect the hoses, and a towel handy just in case. Also, some sort of lighting for under the sink will probably make this much easier.

Step 5: Ready the Solenoids!

Your solenoid should have some kind of indicator as to the direction of flow (mine has a small arrow on the bottom). You're going to want to put the adapter that has a 3/8" female end on the "from" side of the arrow, and the 3/8" male end on the "to" side of the arrow (see first picture's annotations).

Next, grab half of your wire. Each of my pieces was about 6' in length in order to give me plenty of room to place the pedal where I wanted; you can adjust this for your project. Strip about 1" off of each end, and twist the wire up. Loop the wires through the contacts of the solenoid (see second picture). If you're using the solderless method, twist these up, and place a bit of electrical tape over them. If you're soldering them, then twist them up and solder them in place.

Finally, it will make installation easier if you wrap the wire around the valve (see third picture), just in order to keep it out of the way.

Do this for both solenoid valves. You're half way done!

Step 6: Install the Solenoids

The first step, and you're probably not going to like it, is to clean out the area under your sink. It's not fun, but it'll make life a lot easier.

Ok, now that we have that bit of unpleasantness dealt with, we need to find the shut-off valves for the faucet. These should look a bit like the third picture below. Turn these off, and verify by turning on the faucet (test both hot and cold!). Once they're turned off, position your bowl under one of them and disconnect the hose running from the faucet to the valve. Shake out any remaining water, and repeat for the other side. Make sure you keep track of which hose was connected to which valve. If they're not already labeled, a bit of masking tape and a pen could save you some heartache down the road.

Take your first solenoid assembly, and attach it to the valve and the corresponding hose. It's ok to coil your hoses, as long as the coil isn't too tight. I started by attaching the assembly to the hose running to the faucet, and then once that was secure, I attached it to the valve. Make sure you don't kink the hose as you tighten it. Repeat for the second valve. I made sure to position my solenoids "upright", so that if there were any leaks, they wouldn't come into contact with my electrical connections.

Turn on each of the shut-off valves and make sure you don't have any leaks. Water will only be flowing from the shut-off valve to the solenoid right now, so that's the area to focus on.

Step 7: Connect the Wiring

Uncoil the wires from around the solenoid assemblies, and bring the unconnected ends together. You're going to want to twist these together, so that each twist has one wire from each solenoid (see second picture). If you're using speaker wire like I am, twist the two silver parts together, and twist the two copper parts together.

The next part will sound complicated, but it's very easy. Starting at the top of the picture and working counter-clockwise, we're going to:

  • connect one set of the wires from the solenoid to the black wire of the AA battery pack
  • connect the red wire of the AA battery pack to the black wire of the 9V battery pack
  • connect the red wire of the 9V battery pack to one post of the foot switch
  • connect the other solenoid wire to the other post of the foot switch

That's it! It doesn't matter which pair of solenoid wires you use, or which part of the foot switch you use. You can just twist the wires together and cover them with electrical tape, but your project will be much more durable if you solder and insulate these connections. If you're using the 12V adapter, use the black wire of it in the first connection, skip the second, and use the red wire for the third connection.

Step 8: You're in Business!

That's it! Make sure your shut-off valves under the sink are turned on, turn on the faucet, and step on the pedal. If everything went as planned, you should see something like this:

Make sure to check for leaks again, as this will be the first time water will be traveling from the solenoid valve to the faucet. Also, test both the hot and cold settings to make sure both solenoids are working properly.

Hope you find this useful!

Step 9: Version 2.0 and Beyond...

This is a project I've had in my head since I was a little kid, and I can't tell you how satisfying it is to finally see it in action. But there are even cooler things you can do, once you have this basic system installed.

The first thing I did was install a push-on/push-off button into the pedal (wired it in parallel), so that I can convert the sink back to "regular" mode if we have guests using it. Fairly easy, and I'd recommend it.

However, I've also been messing around with everyone's favorite microprocessor, the Arduino, and have some cool modifications in mind. Once I get the solenoids wired up to some relays, it's a simple matter to have the Arduino take control of them. So then you could do something like replace the foot pedal with a proximity sensor, or replace the on/off button I mentioned above with a momentary switch that could set the sink to "regular" mode for five minutes when you press it.

Also, I was on the fence between getting a normally open or a normally closed solenoid valve. Having a normally closed valve allows me to keep the faucet handle "open" all the time, and I just have to step on the pedal to activate it. However, to return it to "regular" mode requires constant power. Since there are just two of us living here, and I'm using rechargeable batteries, I decided this was fine. It would be a simple modification to reverse the pedal and use normally open valves. This would allow the sink to operate in "normal" mode until a button was pressed, which would then activate the solenoids and close them, while stepping on the pedal would break the circuit and cause them to open, allowing the water to flow.

What other possibilities are there with a setup like this? Well, why don't you tell me!

Best of luck!

First Prize in the
Earthjustice United States of Efficiency Contest

Participated in the
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    83 Discussions


    3 years ago

    Has anyone ran into water hammering issues? My downstairs neighbors were hearing all the vibrations and only then I realized that the loud 'thump' was a water hammer. The project was alive for 7 days before I had to disconnect it. Anyone know if w.h. arresters do the trick for typical household pressures?


    3 years ago

    pjamestx it seems like you started this project about 7 years ago. How have the solenoid valves pushed through the time test? Have you had any leaks or any other problems since you installed them? Also have you had any problems with hot water and the valve's plastic parts? Thanks, this is a great project!

    1 reply

    Reply 3 years ago

    I had this project in place for about two years, and everything seemed to be holding up fine. When it was just me using the kitchen, having a normally-closed valve wasn't an issue, because I was used to how the setup worked. However, when someone else was trying to use the sink, I always had to explain it to them.

    I think if I had switched to normally-open valves, other people could have used the sink normally, and I could have switched the valves on and used the pedal to break the circuit when I wanted to use the sink in conservation mode. However, when it came time to adjust the system, it was easier for me to just remove the valves than it was to find some normally-open replacements. I still have the parts in a box in my workshop, so some day I might revisit this project :)

    Thanks for the interest!


    3 years ago

    So with a normally open valve, the thing operates like a normal faucet because you manually have to open the valve to let water out. You only need electricity to close it, but does the electricity need to keep flowing in order to keep the valve closed?

    And with a normally closed valve, electricity opens it, which means it only consumes electricity to keep it open, which is less of the time. So this makes more sense, right?

    1 reply

    Reply 3 years ago

    Right, a normally open value stays open when there's no electricity, so water flows through. When you apply a current, it closes for as long as the current is being applied. A normally closed valve is closed unless current is being applied.

    What would probably be ideal is a normally-open valve, where you flip a switch to turn the current on and close the valve, and then the pedal breaks the circuit, so current is no longer being applied and the valve opens back up.


    10 years ago on Step 8

    Hello, Use some pedals like the one you find in hospital (ER) non electricity, don't have to recharge the batteries etc.

    2 replies

    Reply 3 years ago on Step 8

    getting away from electricity leaves you with 2 options either pneumatic / hydraulic valves and a pump pedal or mechanical valves built in a pedal. Hospitals used the mechanical valves in pedal last I checked. Both of these options are kind of expensive, It would be easy enough at this point to hook up a wall-wart wherever your garbage disposal plugs in and boom no more batteries. The whole build would still be cheaper than mechanical foot pedals. If you got the money and the time I'd probably go that route too. Then again the dream build would be the mechanical hot with a temperature controlled cold. This way you have one pedal that automatically goes to the optimum dish washing temperature. that would run $200-$300 and would require some rather interesting piping. Still don't think it would get the wife to help with the dish washing but it would save water.


    Reply 10 years ago on Introduction

    Those are very expensive, though, and aren't something that can be retrofitted easily.


    3 years ago on Introduction

    I'm totally amazed how a innocent kitchen faucet can trigger most insane ecological-political discussions. But, hey, this one certainly served that purpose. :)
    You didn't expect that, pjamestx, did you. :)


    10 years ago on Introduction

    Fantastic instructable on solenoid controlled sink faucet. I'm enjoying the constructive comments regarding improvements and upgrades. In my home we would like to see something with one solenoid valve controlling a mix of hot and cold water (after using the hand knobs to mix the ratio to our individual preferences.) In the Spokane (state of Washington, united states of America) area, the giant glacier which covered the area from Montanna, through Idaho and into Washington, finally melted away in the early 1800's. Both the natives and the settlers have oral and written records of the change. It was part of the current (naturally occuring) weather events. Political pundits are claiming around the world that the industrial activities of mankind are responsible for melting glaciers. Industrialization occured about 100 years AFTER our local giant glacier melted. Conclusions: Either (1.) we've managed to send our pollution through a time machine into the past and started "global warming" 100 years before the age of oil and industry; (2.) or, the situation has very little if anything to do with our activities; (3.) or, the media hysterics about the subject is another case of brainwashing the public for those who will gain profit or power at the expense of the public.

    2 replies

    Reply 3 years ago on Introduction

    Any changes in your opinion on causes of global warming during last few years, based on the overwhelming world-wide shown evidence?


    Reply 3 years ago on Introduction

    This isn't place for cheap shots mnovak4, but since you asked...
    (And the policy here is "BE NICE" I'll keep my opinions out of this reply and give you facts.)

    United Nations Official Admits the Purpose of the Global Warming Hoax is to Destroy Capitalism

    Submitted by Donald R. May on February 27, 2015 - 4:07am

    It has been clear since the Berlin Wall fell and the Soviet
    Union collapsed that Global Warming (aka Climate Change) is a Marxist

    When the dream of a Soviet Utopia collapsed, Marxists in the United
    Nations, the United States, and Europe needed a quick Plan B dedicated
    to the destruction of Capitalism. Plan B is the claim that the normal
    human use of fossil fuels could somehow catastrophically change the
    climate of Earth and has all along been a Marxist plan to divert
    trillions of dollars from developed nations to the United Nations. The
    goal has been to replace Capitalism with a World economy totally under
    the control of the United Nations.

    The United Nations climate chief
    admitted on 03 February 2015 that the primary goal of the Global
    Warming hoax has been the gradual progressive destruction of Capitalism,

    "This is probably the most difficult task we have ever
    given ourselves, which is to intentionally transform the economic
    development model, for the first time in human history", Ms Figueres
    stated at a press conference in Brussels.

    "This is the first time
    in the history of mankind that we are setting ourselves the task of
    intentionally, within a defined period of time to change the economic
    development model that has been reigning for at least 150 years, since
    the industrial revolution. That will not happen overnight and it will
    not happen at a single conference on climate change, be it COP 15, 21,
    40 - you choose the number. It just does not occur like that. It is a
    process, because of the depth of the transformation."

    As the Sun has been in a normal cyclical phase of producing less
    energy for more than the past 17 years, the average temperatures on
    Earth have been stable to colder during these past 17 years. The Left
    has produced a continuous stream of excuses as to why Earth is not
    warming. Their favorite lies include the claim that all bad weather
    events, including snowstorms and blizzards, are really due to Global

    The Marxists have been seeking to take over the World economy and to
    transfer the massive wealth of developed nations to themselves and their
    cronies. Global Warming is the Marxists best current hoax, which they
    will not relinquish.

    The American people, the House, and the Senate must rise up and tirelessly confront and halt the Global Warming hoax.


    8 years ago on Step 5

    These solenoids are from a clothes washing machine, so if you are throwing out an old machine, you could take them out first.
    You can buy some spade electrical connectors that crimp onto the wire and then plug onto the solenoid instead of having to solder them. They are much easier to remove if you ever need to replace anything.

    1 reply

    Reply 7 years ago on Step 5

    From what I know, the washing machines have AC solenoid valves and here they use a 12V DC solenoid valve. Not the same thing I would guess.


    8 years ago on Introduction

    In my old workplace, there was a manufactured sink with a bar you step on to activate the water. When your hands were greasy from work you could wash your hands without making because you didn't have to touch the faucet handles.

    I always wanted a similar device. I feel stupid for not building one before. I had this knowledge, but never thought about it. Thanks for the instructable. I'd make one eventually.


    9 years ago on Introduction

    Have you encountered any issues with leaving the solenoids under pressure for extended periods of time? Might this have any effect on the life of the part or eventually cause leaks?

    2 replies

    Reply 9 years ago on Introduction

    It hasn't been a problem so far. I tend to do my kitchen cleaning in batches, right when I get home from work, and again just before bed, so when I'm doing that I'll leave the water on, and I tend to turn it off when I finish up. I have forgotten a couple of times, and turned it off in the morning, and I haven't noticed any problems. The valves I used are closed in their powered-off state, so I imagine they'll be fine, unless you have some crazy high water pressure or something.

    Rocky Top

    8 years ago on Introduction

    Thanks for your great Instructable!

    Here's an idea that I tried and works like a champ.

    I wired both the hot and cold solenoid together (in parallel) to a single doorbell button. I mounted the button behind the cabinet door under my sink such that it holds the cabinet door open just a small fraction of an inch. When I need water, I push the cabinet door forward with my knee which depresses the button and closes the circuit. The volume and temperature are controlled with the faucet handle, the flow is turned on and off with my knee. It's nice that no switching device is visible to the casual observer in the kitchen.