Toilet to Tap? No. Toilet to Toilet? Yes!




Introduction: Toilet to Tap? No. Toilet to Toilet? Yes!

About: Semi retired, seeker of knowledge. Fascinated by science , technology and art. Not very good at any of them, but I will never stop trying.

The drought situation in California is severe. Four years of little rain have left water reserves at record lows. Solutions such as "tap to toilet" recharging of drinking water basins generates a tremendous "ick" factor with the general population. It will be very difficult to implement this system. As makers and concerned citizens, it is time to step-it-up. We must create novel solutions for sustainable water use. That being said, I present my small piece of the puzzle solution, the in home, toilet-to-toilet reclamation system.

In an effort to disseminate this idea quickly, so all of you can use and continue development of this process, the documentation of the build will be a little bit more general than I would like. I am counting on the creativity of the maker community to take this idea much farther than I ever could on my own.

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Process, Parts, and Build

The average human produces between 1 and 2 liters of liquid per day. A modern low flush toilet uses between 3 to 4 liters per flush. As you can see, we have a built in ability to supplement the water wasted in the flush process. Lets get started on that build.

Parts used

5 gallon bucket and lid

3- filter disks cut to fit bucket diameter, each 1" thick

Small battery powered fountain pump

2 float switches ( I made mine from a couple of old mercury tilt switches attached to a light duty hinge and a block of foam. Make sure you water proof your electrical splices with silicon caulk)

10 ft of 20 gauge zip cord

Approximately 20 feet of 1/2" tubing and fittings to connect it to the pump. Note: If anyone who will use the recycling system produces a stream like a race horse, increase the tubing to 3/4" to prevent overflow issues.

Fluid receptor ( I used a modified funnel. This is one area that needs a lot of development. I foresee tremendous economic potential in making custom fit fluid receptors based on gender, age and size characteristics. I cannot wait to use the giant vacuformer down at Vocademy to build some really unique ones.)

1 quart of tropical fruit yogurt ( This is to inoculate the filter pads in the bio-reactor)

Beer, lots of beer ( Consumption of beer seems to be the best way to generate flush fluid for testing)


Place your small fountain pump in the bottom of the bucket. Place one of your float switches on the interior wall at a spot where it will open the circuit when the fluid level is too low to pump. You want this switch to close on a rising fluid level. Wire it in series with one of the pump leads, waterproof and attach to the bucket side with epoxy. Run the two wires and the 1/2" outlet pipe out of the top. The 1/2" outlet pipe goes to the toilet tank and should be secured to output liquid above the high water mark. Connect the zip cord to your other switch. Waterproof all connections. You are going to epoxy this float switch in the toilet tank so that it closes on falling water conditions. The activation point should be the high water level of the toilet tank. Wire in your battery pack and test. The only time the pump should run is when the fluid level in the bucket is above the pump and the water level in the tank is below the high fill level. Cut three filter pads to friction fit in the bucket and liberally butter each with tropical fruit yogurt. Install these in the upper part of the bucket being careful not to kink the outlet pipe. Install vented bucket cover and pipe from fluid receptor and you are all done!

Step 2: Operation, Observations, and Conclusion


Your water saving toilet-to-toilet reclamation system can be operated in two modes. The first is a system that will work in tandem with your normal water supply. In this mode simply leave the toilet water supply on. After flushing, if a sufficient accumulation of flush fluid has occurred, the pump will start and assist with filling the toilet tank. The mode I prefer begins with the rigid implementation of the "if it's yellow let it mellow" policy. Although I call mine, "if it's not rank, let it tank" This is more descriptive of what you are likely to encounter. Turn off the water to the toilet and limit flushes to only when sufficient flush fluid has accumulated to complete the flush process.



The dog no longer drinks from the toilet bowl.

The wife no longer uses this bathroom.

In the process of generating test flush fluid I have discovered a lot of really good micro brews.

The bio-reactor emits a wonderful scent of pineapples with a hint of over ripe banana.

We are saving a precious resource.


I have put on 10 pounds from drinking so much beer.

None of our friends will come over anymore.

The wife no longer talks to me.

I now hate yellow.


This project can make a small but important contribution in our fight to conserve water. And if you intend to implement it, give me a call first. I have some really great oceanfront property in Arizona that I know you will love!

Happy April 1st everyone!

Make On!


Prank Challenge

Participated in the
Prank Challenge

Be the First to Share


    • Finish It Already Speed Challenge

      Finish It Already Speed Challenge
    • First Time Author Contest

      First Time Author Contest
    • Leather Challenge

      Leather Challenge

    11 Discussions


    4 years ago on Step 2

    How about you just pour some gravel on your lawn and call it a day....

    Seriously though, have you ever seen Chinatown? This is not a new problem for the west coast., I don't know why I feel like I'm the only one who thinks its a bad idea to raise cattle, and grow orchards in the middle of a desert. Lets leave agriculture back in the midwest where it belongs!


    5 years ago

    clearly you must be related to governor brown.


    5 years ago on Step 2

    I'll take the Ocean Front property in much? Is it still for sale? it's May 1st already. lol


    5 years ago on Introduction

    Great idea! I have heard of people keeping a bucket of grey water in the bathroom to fill the tank..


    5 years ago

    How about reusing water from dishwasher or washing machine for flushing the toilet. Seems like a waste that we use drinking water to flush!

    funky creator
    funky creator

    Reply 5 years ago

    how do u know?