How to Test a Potentially Leaky Toilet

October 30 2015

If you see puddles on your bathroom floor or water spilling over your toilet, it’s clear that your toilet is leaking. However, sometimes a leaky toilet does not provide such obvious signs. Toilet leaks are often silent or are not in clear view, so they frequently go unnoticed. If your toilet keeps running or is making strange noises, that may be a sign of a leak. If you have to hold down the flusher to empty the tank, or must jiggle the flusher to make it stop running, your toilet definitely has a problem.

How to identify a leak

Though there are other ways to identify if your toilet is leaking, there is one easy, fool-proof test called the “Dye Test.” All you need is a dye capsule, food dye or even instant coffee. Anything that will change the color of the water will suffice. Here is how you perform the test:

Remove the lid of the toilet and pour in the colored dye
Make sure that nobody uses the toilet and wait about 30 minutes
After time has passed, check the toilet bowl for any colored water
If the water is a color other than clear, you have a leak

How to identify the source of the leak

Now that you know there is definitely a leak somewhere in your toilet, you need to find out where that leak is in order to determine how to fix it. Luckily, there is another very simple test you can do on your own to determine the source of the leak. If your toilet is leaking, the leak is either coming from the flush valve or the refill valve.

First, turn off the water supply.
Take a pencil (or any type of writing instrument) and draw a line inside the back of the tank at the waterline.
Wait about 30 more minutes before checking the toilet.
If the waterline has not dropped, the leak is coming from the refill valve. If the water now falls below the line you drew, the source of the leak is the flush valve.