toilet tank water savers

We noted our toilet usage for a week at home (62 times for 2 toilets). We both work full days, so these 62 times were only before or after work, and on the weekend.

Did you know?
If your toilet is from 1992 or earlier, you probably have an inefficient model that uses between 3.5 to 7 gallons per flush. New high-efficiency models use less than 1.3 gallons per flush—that's 60 to 80 percent less water than their less efficient counterparts. (source: EPA WaterSense®) Both our upstairs and downstairs toilets are rated at 1.6 gallons per flush, which is typical of about 60% of toilets sold today (1/2009).

Why is Water Efficiency Important?
See this page from the EPA's WaterSense Program

What are the Benefits of Water Efficiency?
See this page from the EPA's WaterSense Program

How Toilets Work
This is a great video that you should watch first from HowStuffWorks: Deconstructed How Toilets Work

Typical Water Usage in a Home
The numbers below do not count for landscape water. (source: Utility Services of Alaska)

Toilet flushing – 40%
Bath and shower – 32%
Laundry – 14%
Dishwashing – 6%
Cooking and drinking – 5%
Bathroom sink – 3%

Toilet Water Saving Tests
Well I'd like to give you gallons saved per flush by method or product, but in the end I've decided that the best measure is how long it takes the toilet to refill. All toilets are different in mechanics, tank size, bowl size, flush rates, performance, and settings, including my own downstairs toilet (used for the testing), which I don't believe is functioning perfectly to manufacturer's specs. So even though it's a 1.6 gal/flush, I don't really know that to be true. So I'm not giving you gallons per flush savings calculations.

Using a stop watch I have recorded the refill time on my downstairs toilet only, and will post those photos at the end of each product/method review. The time it takes to refill the tank, represent the amount of water used in flushing the tank. So shorter times mean less water was needed to refill the tank, and thus less water was used during the flush. I think this will give the best relative idea of water savings, without all the messy math.

Test Toilet: Refill time, No water saving measures (about 42 seconds)

My tank is above, with my stopwatch showing how long it took from the time the flapper closed to the time the refill valve shut off. I chose the flapper closing as a good timing starting point, but actually the refill valve is already open and refilling as soon as the tank is flushed. That's also why my numbers below are to be taken as relative numbers by product/method and can not be used to calculate actual water usage or savings per flush.

Keep a few things in mind
Anything that reduces toilet water from flushing is going to save you money. Buy any of these products, or implement the other methods and you'll be seeing return on investment within months. So do something, and don't worry so much about the actual savings.

Here's the second thing. Toilets need a certain amount of water in the tank to flush down and activate the siphon effect that sucks the bowl clean. Anytime you reduce the toilet tank water, you need to balance water savings with performance. If you really want to save water, your toilet wouldn't have a tank at all, but then it wouldn't flush! So reduce water in the tank to the point were it still can perform well. If you find you've reduced the flushing power so much that you need to flush it twice, or more times to fix a clog, then you will not be conserving water at all. Find a good balance. This is a great video that you should watch first from HowStuffWorks: Deconstructed How Toilets Work

And here's the third thing to note. When your toilet refills, most of the water fills the tank back up, but some of it (through a rubber or plastic tube into the overflow tube) goes down into your bowl to bring the bowl water level back up. Thus, you can also save water by reducing how much water is used in refilling the bowl water level. The tank and bowl refills are related, but can be reduced separately and both approaches should be experimented with.

1. Adjusting the Spring Clip on the Refill Valve
How it works: First I must confess, that after the extensive tests with the "Toilet Tummy" and "Water Bank Toilet Dam", I did a little more Googling and found something I had stupidly overlooked all along. You can adjust the tank water level on some toilets by pinching the spring clip on the rod that hangs down from the refill valve and moving it up or down. This then determines how much water is needed in the tank to shut off the refill valve. I was able to move the spring clip down to a level that refilled that tank just as fast as the "Toilet Tummy". Ah hindsight is 20/20. Well that's why I post these articles, so you can "learn from my experiences..."

Adjusting the clip down will shut off the refill valve sooner. This means less water in the tank and less time to refill the bowl with water. If you want still less water in the bowl, then the "Fill Master" product below would still be of use.

Although I didn't see a mark, most overflow valves (big white vertical tube shown above) or tanks, have a line indicating the manufacturer's recommended water level. Also, you never want to adjust the tank water level higher than the overflow tube, else your toilet will be sending water into the bowl constantly. Setting the water level about an inch below the overflow tube seems to be a general standard.

Adjusting Spring Clip Refill Valve: Refill time (about 30 seconds)

This is the same time as with the Toilet Tummy below. You might still want to use anther product to reduce the water level even more, if the spring clip adustment doesn't get you as low as you want. Also you can adjust the height of the whole refill valve mechanism, and a good article that includes that adjustment is here.

2. Adjusting Refill valves on Toilets with Ball Floats
Toilets with a ball float on the end of rod, can be adjusted by turning the screw on top of the refill valve, where the rod attached. If that doesn't do enough for you, you can bend the rod down a bit to lower the float in the tank, thus shutting off the refill valve off. you may want to remove the rod before you bend it, as not to damage the refill valve mechanism.

Here's the upstairs toilet (not used for the rest of the testing), with a ball float type refill valve. The refill time is about 22 seconds as I found it.

Here's were the screw is that will adjust the level of the float, and thus when it says the tank is full.

Here's a close up of that adjustment screw. If you tighten the screw, it lower the float and thus less water will enter the tank.

Here after tightening that screw about 40 full turns, I've gone from the original refill time of about 22 seconds, to about 13 sections. It still flushes well and there is plenty of water in the bowl on refill.

3. "Toilet Tummy"
How it works: You fill the bag with tap water, hang it inside the toilet tank, which reduces the amount of water to refill the tank.

And here it is installed in our downstairs toilet. The directions suggest to hang it on the left side if there is room there (not interfering with the parts). There was no room on that side, so I did as they suggest as a second alternative, to hang it on the right side. The lid fits fine over the top of the clip. The bag comes quite close the flapper at the bottom of the tank, but does not interfere with the flapper or the float attached to the flapper chain. the Toilet Tummy encroaches into the tank roughly 5.25" at it's widest near the bottom, and hangs down into the tank roughly 11". The clip can accommodate up to a .5" thick tank edge. The water fill opening at the top allows some water to evaporate over time, so you either have to check that periodically, or perhaps seal it shut.

Toilet Tummy: Refill time (about 30 seconds)

Tummy installed on a toilet with a float lever

Here's our upstairs toilet which has different moving parts than our downstairs toilet. The right was taken by the float (which moves up and down during flushing), and the left side seemed too tight, but after a bit of convincing. The Toilet Tummy fit in there, squeezed in a bit, but not interfering with any moving parts.

Cost: $3.69
Where to Buy: AM Conservation Group
Similar Products
Mountain Wind & Sun: "Toilet Tank Bank" Cost: $1.99
Choose Renewables: "Toilet Tank Bank" Cost: $2.99

4. "Water Bank™ Toilet Dam"
How it works: You insert the flexible dam into the toilet tank and it's rubber sides and bottom form a seal with the tank. When you flush the toilet, the Toilet Dam holds back water that is behind the dam. The product comes with one dam, enough to dam one side of the tank, but you can also use two, one for each side. AM Conservation Group, the manufacturer, recommends one dam for toilets that are rated at 3.5 gals per flush, and 2 dams for toilets that are rated at 5–7 gals per flush. They also state that the product is "not recommended for newer 1.6 gallon per flush toilets".

Here's the Toilet Dam installed and in action. You can see that water behind the dam doesn't flush. The Water Dam is movable, so you can decided how much water you want to dam. The flexible rubber sides of the dam need to form a seal with the bottom and the sides. My tank has a decorative indent at the bottom edge, which didn't make the seal perfect, but because the flushing is so quick the amount of leakage in that area was minimal during the time the flapper was open. Also I have a few screw heads in the bottom of the tank that I worked around.

Water Bank™ Toilet Dam: Refill time, one dam (about 37 seconds)

Cost: $5.25
Where to Buy: AM Conservation Group

5. "Fill Master™"
This product is different than the first 2, in that does not reduce the amount of water the tank holds, instead it reduces the amount of water used to refill the bowl after flushing. Reducing the water used to refill the bowl will lower the bowl water level, thus saving water.

Here's what you get in the Fill Master package.

Here's a shot of the bowl refill plastic tube, which clips to the inside of "overflow tube". After flushing and water is refilling the tank, some of the water is also sent down this tube and into the overflow tube to refill the bowl water level.

Here's the Fill Master attached to my bowl refill tube, but not attached to the overflow tube, so that you can see what this device does. The Fill Master divides the water flow into 3 separate streams.

One Stream to Bowl Testing

Here's the fill master installed and on the job. As the tank refills, only 1/3 of the normal amount of water from the bowl refill tube goes down into the bowl, the other 2 streams now go into the tank. The bowl fills up less, and the tank fills up faster. If you don't want to reduce the flow to the bowl this much, you can reattach the device so that two streams go into the bowl instead of one stream. And if you want even more water to go to the bowl you can reattach it so all three stream go into the bowl. I can hear you now, "what's the purpose of that?" Well to my surprise, it still reduces the amount of water going to the bowl, compared to not having this device. In short the device is adjustable for what works best for your toilet.

Fill Master: Refill time, one stream to bowl (about 35 seconds)


Two Streams to Bowl Testing

This is what it looks like with 2 streams going to the bowl, and one stream out.

Fill Master: Refill time, two streams to bowl (about 38 seconds)


Three Streams to Bowl Testing

This is what it looks like with 3 streams going to the bowl, and no streams out, the left most peg is only there to clip the device on the overflow tube, it is not a stream opening.

Fill Master: Refill time, three streams to bowl (about 40 seconds)

Cost: $3.49
Where to Buy: AM Conservation Group

No Water to Bowl Testing

And if you are asking yourself why have any water go into the bowl at all, here's what that would look like. Yes, it fills the tank quickly, but the water level in the bowl is so low it's not ideal, but you can try it.

Fill Master (1 stream to bowl) & Toilet Tummy: Refill time (about 24 seconds)

I thought I'd try two products in tandem to see the results. The water level in the bowl was too low though, lower than without the toilet tummy. Why? Well because the tank refill valve shuts off quicker with the Tummy in place, giving even less time to fill the bowl. The ideal combination for me might be to use the Tummy, but have 2 streams of the Fill Master filling the bowl. I'm going to try that for a while.

6. Half Gallon Plastic Milk Container
This is a very economical and green approach to reducing water in the tank. You could also use old soda or water bottles.

You can't see it here, but I've cleaned it, and filled it with water. Would be good to remove the label too, so that it doesn't detach in the tank causing "issues". I found that with just water in it, the bottle tends to move about a bit. So I'd also recommend adding some pennys, rocks or something heavy to keep it in place.

Plastic Milk Container: Refill time, (about 37 seconds)

This had a similar refill time to using one Toilet Dam, but there is one disadvantage to this approach over the Toilet Dam or Toilet Tummy. If you have a ball type float attached to your water refill valve, you aren't going to have room for a milk container. That's the nice thing about the other two devices, you can work both of them around obstacles. One advantage this has over the Tummy is that it doesn't lose water to evaporation, as the Tummy does with it's opening at the top.

7. Install an Early Closing Toilet Flapper
In order to conserve water in your pre-1994 toilet you can install an early closing toilet flapper, which are available at participating local hardware stores. (source: Cary, North Carolina - Water Conservation Tips)

8. Replace Your Toilet with a High Efficiency Toilet
The EPA WaterSense program certifies any toilet that is below 1.28 gals per flush as a "High Efficiency Toilet". Of the approximately 249 models they are aware of on the market, "more than 100 models meet that specification. While gallons per flush are lower, standard for flush performance must also meet specific measures. The EPA states that price has little to do with performance, and that price is mostly related to style and other features. High efficiency toilets can be purchased for less than $100, while most are in the low to middle $200 range. in addition, your water utility may offer rebates for replacing older toilets with high efficiency WaterSense certified toilets. Here's a link to all of the currently WaterSense certified toilets. Here's an example of one.

9. Add Bricks to the Toilet Tank. AKA "The Brick Trick"
This is the what your parents might have done, but it's not recommended as the bricks have been know to disintegrate. The brick crumbs can get caught in the small channels and holes under the toilet bowl rim, where water needs to enter the bowl to refill it. If those get clogged, you could end up having to replace your toilet. Brick debris can also interfere with the flapper closing properly. Also, one brick will not displace much water, as the tank always has about an inch of water in it that never leaves the tank anyway. If you want to use bricks then it's a good idea to seal them in a Ziplock bag, or other tight plastic bag first. Also, if you drop the brick in, you could crack the tank!

10. Float Booster
See: Eartheasy Shop for details

11. Reuse your bathroom sink water for toilet water!
WaterSaver Technologies: AQUS System

12. If it's Yellow, Let it Mellow. If it's Brown, Flush it Down
There are few things that will cause as much controversy as this water saving technique. Your either strongly for it, or strongly against it. Check with your living mates first, to see what they think. I'd also recommend you don't do this at other peoples places, before you know their views on this. In general it leads to more regular bowl cleanings being needed, which could mean more toxic chemical usage. A practitioner, found on the web, stated, "it's a good idea to always flush once in the morning and once at night, if you are using the let it mellow technique." Along with this idea, there are a few more that I'm not weighing in on, I'm just presenting them as other options: 1. Pee in the sink, Pee in the shower, Pee outside, Pee in a bottle and then take it outside.

13. Wash Your Hand with Clean Water Before it Refills the Tank!
eHow: How to Save water by using water from your toilet water tank.
Buy at Sink Positive

14. Dual Flush Toilets
Here's an example of a dual flush toilet from Kohler. You have the option of 1.6 gals/flush or .8 gals/flush, depending on the need.

15. Add a Pickle Jar or Similar to the Tank
Found this one on the Web. They say to add a jar with the lid off, so that it refills with water. I've not tried it, but I'll give it a go. I don't like the idea of glass in there much.

Interesting Note
In colder climates, the water entering the tank is very cold (I know from reaching in). The more cold water that comes in, the greater the heat loss in the house. A detail, but interesting food for thought. (source: James Dulley,

This is first thing in the morning, so the tank water has been sitting overnight with no flushes. The bottom of the tank shows about 61.3 degrees F. The indoor temperature was 62 degrees F. and the outside temperate was 18 degrees F. I'm using an infrared temperature gun to measure the tank temp.

And after flushing once, and waiting about 5 minutes, it's now at about 55.9 degrees F.

The National Average Cost for Domestic Water
According to the NUS Consulting Group in their 2007 International Water Survey, the U.S. has the lowest average cost of water at $0.70 per cubic meters. A cubic meter equals 264.172 U.S. gallons. The average average cost per gallon of water in the U.S. in 2007 was $0.02649 (or 2.649 cents per gallon)

EPA: WaterSense Program
The Family Handyman: Replace The Toilet Fill Valve, Flush Valve or Flapper

My Standard Disclaimer: This is what I did. This does not mean this is the best way, the right way, to building code, or even safe for your needs. So you are on your own with your project. I make no promises about the information presented here. I'm just a do-it-yourselfer, not a professional at all, sharing my story. So if something goes wrong with your project, you are on your own. Good luck, and have fun!

All content and photos, copyright 2009, Dover Projects.

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  1. GREAT info on your toilet fix article. I'm going to go get a Toilet Tummy and Tank Dam (if I can locate them). If not, I'll finish up that liter bottle of soda and sink that!! Thank you for your great notes and photos (from a fix-it myself gal -- so my Dad doesn't have to stick his hands in freezing tank water!!)

  2. Thanks Linda, glad it was helpful. The Toilet Tummy and Tank Dam can both be purchased online if you go to the links under those parts of the article. Also, you might be able to achieve your water conservation goals by simply adjusting the float level. That's explained at the top of the article, but you are right, someone would have to get cold hands!--Peter

  3. i <3 this article! i love the pics, too. i am a very visual person so thanks for this!

  4. Anonymous: Thanks for your kind comments. Now if only I had an editor, perhaps my ramblings would be much more consice, and without speeeeling errors!--Peter

  5. extremely informative!
    the picture.s are very helpful to me/
    both my toilets have low water level in the morning only.

  6. Thank you so much for the toilet float adjustment info! I just got my first water bill in the house I am renting and was not overly surprised at the high water bill I just got, because I knew the toilet seems to take WAY too long to flush. The house was built in 1978 and I suspect the toilet was the one put in then, so the tank is huge. I adjusted the float like you mentioned and the toilet takes only just over half the time to flush now, so I'm looking forward to seeing if the sewage bill goes down.

  7. Sara, glad to hear. Hope it drops the usage!--Peter

  8. I asked the young clerk at Menards and got such a funny look, but I plan on trying Home Depot for a "Toilet Tummy" with better luck! I like your explanation about using a brick in the tank (my Father did that back in the 1940s).

  9. I don't think they have a Toilet Tummy at HD either, but what I found in the end is that I could adjust my toilet to the right amount of water without any extra products. See above for how to adjust the water level in the tank.

  10. NEW!!! DOVER PROJECTS ON FACEBOOK! Join in with your DIY spirit! Click on the BIG blue box for "Facebook, Dover Projects" in the right column above! See you there!--Peter

  11. Peter - what a great article. I have to try the adjustment for the float level. But we have put old spaghetti jars and glass drinks (Starbucks' shakes use glass) and fill those up. They have the added convenience of being heavy already and they definitely save water. We haven't ever had problems with them breaking and they're small enough footprint that they don't interfere with the mechanisms of the toilet. But I'm also going to try just adjusting the float level. Thanks!

  12. Found your article while searching for "toilet tank dam" and learned the "flow master" is what I really need. Thanks for the link that let me order that and a few other devices for this old building but new-to-us apartment.

  13. Hi Peter! which method would you recommend for the old ball float toilets to increase efficiency? I tried adjusting the water level, but the screw seems to be stuck? what do you think about a toilet tummy + dam? or should would toilet tummy + fill master be better? Or would fill master + dam be best? I have a Norris ball float toilet from 1977.

    Thanks in advanced and great article

  14. I've got a ball float and bending the rod was just the ticket. Great call! I'm also planning on putting some river rocks in there, which I think will be stable unlike bricks.


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