Arduino Gives Your Toilet Options

toilet water saver

With the severe drought going on in California with no end in sight, [TVMiller] decided he could put an Arduino and a toilet together to try and save at least a few gallons of water per day. The invention fills a toilet to the minimum level, saving around two gallons per day for the average “user”.

A typical toilet functions by using gravity and moving water to create a vacuum, sucking the waste down and out of the toilet. As long as there is nothing, uh, solid in the bowl, the toilet will be able to function on the reduced amount of water. The Arduino cuts the flow of water off before the toilet fills up the entire way.

In the event that anyone -ahem- needs the toilet’s full capacity, there is a button connected to the Arduino that fills the reservoir to capacity. [TVMiller] notes that if 1,825 hackers installed this device on their toilets, we could save a million gallons of water per year and be well on our way to saving the planet.

The project site is full of more information and puns for your viewing pleasure. We might suggest that the “2” button would be very easy to integrate with the toilet terror level indicator as well.


60 thoughts on “Arduino Gives Your Toilet Options

    1. American toilets apparently fill the bowl instead of a cistern with water, and then rely on the momentum of the water as it goes down. Everyone else uses toilets that drop water down on the poo to push it down.

    2. Not in the typical American home, though they are becoming more frequent in newer construction. . . The level of water wasting that goes on here in California is shocking, especially given that we are in the worst drought in 500 years. Lake Shasta, an enormous and beautiful lake that supplies water to LA has been nearly drained. One can see the bottom. Distressingly, water consumption in that county has INCREASED by 7% this year.

      1. you’d only get splashback if you had the severe squirts… anything else just plops on in with no issue. maybe if the seat was higher vs the waterlevel, then some additional momentum might be gained and more of a splash effect might be had? I don’t think that’s a design goal among toilet manufacturers though. (thankfully!)

        Also, we flush our paper along with our excrement. I’ve been in places where the plumbing system couldn’t support the additional burden of the paper, and I can’t imagine having to live with that… the soiled toilet paper in a bin thing just icks me out, bigtime. I’d rather use an outhouse.

  1. Yeah I’m stuck in cali for now. If it’s yellow, let it mellow. When it’s brown let it flush down. Took a few tries to break the habit of insta-flushing. We use 1/3 of our allotted water. But we don’t get money back, or cash incentives… Could be a reason most people here don’t care to try harder. Our neighbors called the cops on us for watering the grass. Kids are petty here.

  2. They have installed water saving toilet at my apartment and the new one (made in China) actually flush a lot better with less water. The seat is a bit narrow for the 30%+ population. Thankfully I am not in that group. The new water saving shower head doesn’t work as well.

    In some countries, they don’t waste drinking water for flushing toilets.
    >In 1991, about 65 percent of Hong Kong’s households used seawater for flushing. By 1999, the number of conforming households had increased to 79 percent.

    1. How about not having lawns where there isn’t enough water for it? The amount of water wasted on lawns are scary (literary wasted – a big part of the water evaporates before the grass can consume it).

  3. I never quite understood the expression “Dropping the kids off at the pool” until I used an American toilet. Yeah, definitely danger of splashback.

    From my understanding, dual flush toilets are mandatory here.

    The US toilets are less likely to have waste cling to the bowl, but clog more easily. The ones here in Australia, it’s not uncommon for the occasional bit of waste matter to cling to the bowl. but they clog far less often.. This is why in Aus you’re more likely to see a brush next to the toilet, whilst in the US, it seems to be a plunger.

    1. So true. On both trips I’ve been on to the states I’ve been worried about ‘Tea-bagging’ the toilet water. I’ve had plenty of splashback from US dunnies too.

      A good trick I’ve found for removing Klingon’s is to use a motorised SuperSoaker. That way you stay well back from the bowl and don’t drip loo water on the floor or seat when putting the brush back.

  4. This is pretty ridiculous. At least a third of the toilets I install (residential plumber in Ontario) have two buttons and of the ones that don’t, the majority don’t flush the full tank unless you hold the lever down for a few seconds. Depending on the make and model, just touching the lever only uses 1/4 to 1/2 the water in the bowl. Spending electricity on something like this is just silly, especially considering lost of jurisdictions have rebates on new toilets. A basic toilet here from Home Depot after a rebate is $80 if you wait for the sales that come up every month or two.,

    1. Yep – was going to say the same thing – I’m in Arizona and all my toilets operate as you describe. Costco had/has the dual button kind for about $80 with the gentle close cover as well.

    2. 1. “Spending electricity”…it’s a 9 volt battery.
      2. I’ve installed hundreds of toilets in CA and FL and they have all been 1.4 to 1.6 gal flush. This isn’t ridiculous in a state where water IS precious and toilets ARE wasteful. You have to consider that not every one (more every one) does not want to buy a toilet and have it replaced. THIS is 20 bucks to drop in and done, like a blue tab. Idealistically it’s more practical if it were available.

  5. 1,825 people spend about $30 a pop or $54,750 to save 1 million gallons of water per year. Meanwhile, wikipedia says the cost of desalinizing 1 million gallons of water in America would be about $2,900. Congratulations, you actually managed to come up with a water system that’s LESS efficient than desalinization. That’s an accomplishment.

    By the way, a dual flush toilet can be had for $100 at Home Depot, about $30 more than the cheapest single flush toilet.

    1. And dual-flush converters can be had for $20 to $25, and fix all toilet tanks. Not thread-crapping (oops, toi late), but this is a waste of an Arduino, tanks any way. Water else are you doing with your Arduino? :)

      1. No, they’re suggesting that although this is a neat hack, if people had spent the $30 to get the dual flush toilets in the first place, there would be hundreds of millions of gallons of water saved in North America a year.

    2. Desalinization SHOULD be the way CA went a long time ago but, bureaucrats. Side that, it would cost millions to build one, appropriate the systems and run it. 20 bucks and you can contribute now. It’s more about effort than complaining.

  6. Many places in the world have no shortage of water – most of Canada, many countries in Europe, etc. Even many US cities have no problems with water supply.

    For areas where fresh water is scarce, it’s a neat idea. Even bigger water savings can be had if you can cut down water use for showers; a 10 minute shower shower can easily use 20 gallons of water.

    1. While Canada may not seem to have a shortage of water, most of the water that is available is polluted (some first nations communities in Canada have water quality that would shock third world citizens). In addition, there is a substantial cost associated with gathering, treating and distributing water. As communities grow, the incremental cost of providing more infrastructure for new residents’ water supply is high (e.g. once the capacity of a treatment plant is exceeded, a whole new plant is required). So the practical solution is to conserve water.

      Low-flow, dual flush toilets should be mandatory in all new construction (it is in some communities). Low flow showers are also a really good idea. Wasting water is bad economics and bad for the environment. This is true whether you live in Toronto or Iqaluit.

  7. With a very long sewer line I need a good flush for #2. I put in an older stool one that holds less water in the bowel and has a full tank. I found I could squeeze the handle part way and let 4 seconds of water past and get a full flush. Thus this is a real saver for #1.
    This a “washdown” type toilet, what the rest of the flushing world seems to use. They are not supposed to be code anymore. The far-east finds the splash very disgusting! The modern toilet is the “reverse trap” with it’s swimming pool of water that has to gain momentum to get going. A friends new up to date stool has me worried when I flush it. Water spins for several seconds and comes right up to the RIM! occasionally wetting the top of the rim. In America we can’t be trusted to brush rim-bowel, but we have Rush Limbaugh whom I call Brush Rim-Bowlgh. There is a place to be conservative.
    On a technical note, couldn’t a 555 do this? Beware of dampness causing various electric problems in the tank. Seawater in interior pipes, sounds like problems in the future.

  8. 1. No mention that it’s also BLUETOOTH enabled. Touch-less flushing.

    2. Watch the video for much more amusing HackADay friendly details

    3. PLEASE give it a skull on HackADay Projects

    4. This is about simply dropping this in (pun) versus buying and installing a whole new toilet. Millions of American toilets just replaced willy-nilly is irrational. Boom, this.

    5. (contd) AFL actually uses less (very less but some) water than the dual flush

    6. As a seasoned journeyman plumber my self, I installed a lot of toilets in CA and FL and most were the flapper and float which uses exactly to standard what the toilet flushes, commonly 1.4 to 1.6 GAL. This simply applies to the millions of those by cutting the need to fill for urine.

    Toots McGee!
    Thanks for skulling, viewing, clicking, et cetera’ing.

    1. Yes, a “touchless flush” via bluetooth. Means it can be hacked and…waste water. In fact, a potential way worse problem of blowing up pipes via a syncronized flush.

      Everyone here looking to “save the world” with less “shit water”, do you have to clean the sewers when there’s a clog from no water flushing out the shit? I still don’t understand where all this shit goes, besides our water supply.

  9. “[TVMiller] notes that if 1,825 hackers installed this device on their toilets, we could save a million gallons of water per year and be well on our way to saving the planet.”

    What planet would that save? A million gallons saved per year isn’t squat. This is exactly what’s wrong with all the tree huggers – they can’t do basic math, nor be bothered to look into actual statistics on what we have, what we produce, what we use, etc.

  10. on the one hand; FINALLY someone has made a multi-flush toilet aka variable-flush!
    this, combined with a LARGE outdated HIGH-FLOW toilet, would be what “should exist”

    on the other hand it’s a little too late for conserving the aquafier in cali…
    its almost gone and naturally takes a reeeally long time to fill with NON-SALT water…
    might need a desalination plant…

    oh, and all the HI-FLOW toilets are smashed in the landfill,
    so even when this guy fills his tank all the way (with his arduino)
    it will STILL need a total of 3 flushes per use,
    assuming it doesnt clog,
    which would add an extra “flush while unclogging” flush…

  11. Cool hack. Once water is more scarce hopefully it’ll drive us away from wasting what we have needlessly on flush toilets. Convenience is nice, but I’d poop outside for the sake of knowing water doesn’t become the new oil.

  12. Someone mentioned incentives for conserving water. And the cost of building water treatment facilities.
    Now, correct me if I’m wrong, but isn’t water-supplying a privatized industry in the U.S.?
    At least it is here; I just paid 250e for my last 3 months’ water.

  13. Can’t you manually adjust the water level on an American toilet? As people have pointed out above, before Australian dual flush cisterns the old trick was to reduce the tank capacity by putting a brick in it or adjusting the ball-cock (that’s what it’s called!). And the project says the average person pees twice a day! See a doctor!Yet more ammunition for the Arduino-haters.

    1. 1. You can adjust the float or capacity to a point but there is still waste. This refines it with more treats.
      2. According to medical studies, people expel 800 to 1200 mL of urine a day. I tested and per trip, I displaced 400 mL (avg) so that’s 2 pees and 1 pee during the poo for average. Thus, averaging 2 low flushes and 1 high flush for the stats in the video…

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