How to Check for a Leaky Toilet

Did you know that a leaky toilet can waste about 200 gallons of water every day?
(source: EPA WaterSense®)

Simulated leaking toilet, tested with blue dye tablets. (Note: click on photos to enlarge them)

Testing blue dye tablets to check for a leaky toilet
As part of my effort to make our house more "green" I thought I'd try a few products/methods of reducing the water we use per flush. I've written about that subject in an article here toilet tank water savers. When I ordered those products for AM Conservation Group, I also notice an interesting product. It's a toilet tablet that you drop into your tank to check for a leaky toilet. What follows is a review and testing of those toilet dye tablets. For those of you that just what the results, they are next, if you want to know how I came to these conclusions, you'll need to read the entire article. If you want to fix a leak between the toilet and floor then see Reader's Digest Article: How to repair a leaking toilet.

The Results:
1. The package says use one tablet. I suggest you get 2 packets per toilet and use four tablets. One doesn't make the water dark enough to identify smaller leaks. Also you can get them for $0.88, for 2 tablets, not much of an investment for what could save you much money.

2. I'd place these 4 tablets evenly spaced, close, and on all sides of the toilet flapper or flush valve (the mechanism that let's water down from the tank into the bowl). See how toilets work here. The reason for this is to make sure you get a thick cloud of concentrated blue dye around the flapper from all directions.

3. I wouldn't stir that water to spread the dye out, as that makes it diluted throughout all the water in the tank, thus making it lighter. Let it mellow out and drift in from all sides, in a thick blue cloud. I'd perhaps gently crunch up the tablets if they are not dissolving, with a paint stirrer or something, but I'd so without disturbing all the tank water. You want the dye really concentrated around the flapper.

4. Give it a good 30 minutes, rather than 10-20 as suggested, just to be sure.

5. Other websites suggest using 4 or so drops of food coloring. I've not tried this, but it might work just as well, again, you are going to need a dark cloud though, and I don't know if the food coloring would stain your toilet. I'm guessing 4 drops wouldn't tell you much. I'm guessing you'd have to add more like the whole little squeeze bottle, but again, I've not tried it.

6. Yet another way to test for water leaking from the tank into the toilet bowl, is to turn of the supply valve to the tank (knob on left side of toilet going to tank), mark the water level inside the tank with a pencil, then check the water level 30 minutes later. If you have a leak the water level will be lower of course.

7. If you have a leaky toilet, there are most likely other signs that will tell you that there's a leak, rather than having to use dye. You might hear trickling water noises (toilets shouldn't make noise when resting), you might see ripples in the bowl, you might have periodic phantom flushing, or gurgling. While the dye will help you check for a leaky toilet, I'm not sure that you wouldn't be aware of a leaky tank without dye testing. Sure is fun though.

8. If you have many toilets to test, such as in a commercial installation, these might be just the ticket. Drop 'em in and check your 20+ toilets later.

Whole House Leak Detection
I learn this alone the way in my internet surfing about leaky toilets. That if you look at your water meter, there is a tiny dial (on my it's at about 10:00 on a clock dial, between the center of the meter and edge of the meter). It's called a "leak detection gauge". If that thing is spinning at all, you have a leak inside or outside of your house. Here's are great article about "leak detection", that I found on the Nipomo, California Community Services District website. I tested this by setting our kitchen faucet dripping just a few mini drips, and sure enough the dial caught it. So if you want to do a whole house check for leaks. Check the leak detection dial. Also if you take note of the meter reading and then read it an hour later and it has changed, you have a leak. Besure of course that nothing is using water (ice maker in the fridge, washer, toilets, etc.) The link above will tell you more about testing for whether the leak inside or outside your home.

Leak detection gauge on my water meter.

Here's the product being tested and my experience with it.

Here's what you get, with 2 tablets inside. The directions say to drop in 1 tablet into the toilet tank and wait 10-20 minutes. If blue water appears in the bowl, you have a leaky toilet.

The tablets are blue and small.

Here's my bowl prior to adding the tablet.

A few seconds in, and you can see it starting to work it's magic.

Here's what the tank looked like after I waited a full 20 minutes, and the bowl looked just as it does in the first picture. So by their directions, I do not have a leak. But I wasn't satisfied with the dissolving of the tablet. You can see that much of the tablet is still in a clump, and what water is blue, is not very concentrated, particularly around the flapper, where you would have, and want to check for leaks.

So I helped the process a bit by stirring it with a paint stick to mix up the clump. Still no blue in the bowl, so, as I suspected I don't have any leaks. Never thought I did, I just wanted to see how the product worked.

But I was still a bit unsatisfied with the density of the dye, so I added the second tablet. Hey, I had a few to play with.

After the second tablet, I broke that one up too with the paint stick and gave it a stir. Looks fairly dark now. Still no blue in the bowl. Good!

Another check for a leaky toilet and luckily no sign of leaking. By the way, this is a Kohler toilet which I found there quite a lot of internet searches for "kohler toilet leaks from tank". In fact when I researched the types and number of searches being conducted for "leaky toilets", it turns out that search phrase "kohler toilet leaks from tank" is by far the most searched on phrase, followed by "kohler toilet leaks problems", related to this topic. My Kohler toilet is working perfectly though. To be fair to Kohler, perhaps the majority of toilets out there are Kohler, so that might be why this is a common search and not because Kohler toilets are any more leaky than any other toilets. I don't know.

But as this is a test, I thought, I'm going to get a bit of that blue water out of the top of the toilet tank with my drip counter, also from AM Conservation Group, and put it into the bowl to see what it would look like with a leak. Hard to see in the photo, but the beaker is to measure drips from a faucet. You are supposed to stick it under a leaking faucet for 5 seconds, pull it away, and then read the marks on the corresponding water line. I decided I'd fill the beaker to what is equivalent to 5 seconds of leaking at a level that's equal to 40 gallons a day, figuring that if my toilet was leaking that much a day, I'd want to know about it. By the way, the beaker's also indicates that would be equal to 14,580 gallons of leakage per year.

So I poured the blue tank water from the beaker into the bowl, and as you can see, there was no visible change. Now I'm starting to question whether the dye idea works at all.

So now I fill the whole beaker with with blue tank water, at a level equal to 5 seconds of leaking that would yield 200 gallons of leaking tank water per day, which translates to 72,900 gallons of leaking water per year.

I pour that full beaker into the bowl and sure enough, no visible change. Now I'm starting to think, "this is getting interesting". NOTE AFTER TESTING AND WRITING: But after thinking about it. I did stir up the tank water, which was not part of the directions. When I stirred the water, what I essentially did was dilute the dye color by mixing it with the whole water content in the tank. Prior to mixing I had a dark cloud of dye in the bottom of the bowl, where I think it's intended to be in concentrate, but my problem was that it wasn't around the flapper. That's why in my results section (above) I suggest not stirring, but using more tablets, near and around all sides of the toilet flapper. Also pouring the beaker water into the bowl made it mix with all of the bowl water, and is thus more diluted and hard to see. In my simulated leak below, I can see that the blue dye comes in more concentrated and not mixed with all of the bowl water, so perhaps, my pouring tests were flawed in execution.

So skipping ahead a few increments, I decide to fill a measuring a 2 cup measuring cup. Which is equal to 24 full beakers fulls, for a total of 4,800 gallons of water leaking per day, or 1,749,600 gallons leaking per year.

I poured the 2 cups of blue tank water into the bowl, and sure enough it was blue!

I've decided to simulate a real leaky toilet

So then what happens when you have a real leaking toilet? I folded up a short piece of foil insulation tape and stuck it under a section of the flapper, so that it couldn't make a tight seal. I tried to simulate a slow leak. It wasn't easy, as I either had too much flow into the bowl, or not enough. You can see above that I've got the metal tape under the flapper, and I've dropped in 2 tablets. You can also see a few ripples in the water in the bowl, from my simulated leak.

A few moments later, and there it was! Blue was coming into the bowl quite quickly.

And after a few minutes, the bowl was clearly blue. Success!

AM Conservation Group: Leak Detection Dye Tablets

Denver Water Org.: Repair a Leaky Toilet Testing for Leaky Toilets Toilet Care and Repair Course
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. 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

  2. Have you ever had a slow leak from the incoming stand pipe which runs into the overflow pipe bypassing the bowl or flapper?


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