How to catch a running toilet

Blog Post
Woman with crazed facial expression enthusiastically points at a toilet with blue water in the bowl.
Toilet leaks are the most common household leaks. There’s no better time than Fix a Leak Week (March 18-24) to track down household leaks that waste more than ONE TRILLION gallons of water nationwide each year.
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Check your meter 

If your home or business has its own water meter, it’s a great place to start checking for leaks. By looking at the leak detection dial on the meter, you can check for leaks you can’t easily see or hear

Illustration of a water meter face showing the sweep hand, which rotates on the meter face like a watch hand to measure water usage, and a leak detection dial, which is a small shape that rotates when there is a water leak.

Check your toilets 

Text that says “Toilet Leak detection Dye Tablets” with a graphic of a light blue water drop wearing sunglasses and dropping a leak detection tablet in the toilet
Order your FREE toilet leak detection dye tablets today!

Toilets are the most common source of leaks. If you’re unsure about how to check your toilet, don’t worry, we’ve got you covered. It only takes a few minutes! 

  1. Remove your toilet tank lid. 
  2. Drop ten drops of food coloring into the tank. 
  3. Put the lid back on and don’t flush. 
  4. Wait twenty minutes. 
  5. Check your toilet bowl. If you see colored water, you have a leak. If not, you don’t.   
  6. Check again in six months. It’s good to check at least twice a year to catch leaks before they get bad.   

Don’t have food coloring around? Order a water efficiency kit and we’ll send you a set of leak detection tablets that you can use instead.  

Fix a flapper in five easy steps 

A diagram of the inner workings of a toilet
Diagram of a float-ball-style toilet. Learn more about the different toilet types.

In the toilet, the flapper is really the magic behind the flush. This rubber or plastic part allows water to “flush” from the tank into the bowl and down the drain. 

Flappers typically last about five years and are often the source of leaks when they no longer fully seal. You can repair or replace a flapper with the quick, easy steps below.  Learn more about flappers with these how-to videos. 

  1. Stop water from entering the toilet by turning the water inlet shutoff valve clockwise. This valve controls the flow of clean water into the toilet tank, and it’s often found on the wall below the back of the toilet. 
  2. Flush the toilet to drain the tank.  
  3. Check the flapper to make sure it lines up with the valve seat. If it doesn’t line up, you’ll need to buy a new one. Replacement flappers can easily be purchased at hardware stores and some large grocery stores. Take your old flapper with you to make sure you get one that fits.  
  4. Attach the new flapper. Hook the chain in a position where it rests without pulling the flapper up (causing a leak) or hanging over the edge.  
  5. After installing the new flapper, open the water inlet shutoff valve and flush to test. 

Replace your toilet and get a rebate! 

If repair isn’t the answer, the Portland Water Bureau offers a $50* rebate to replace your old toilet with a water-efficient model. Learn more about our toilet rebate program.  

*Single-family residential customers enrolled in the bill discount program are eligible for a rebate of $100 per toilet. 

Get help with repairing a leak 

The Water Bureau works with community partners and local plumbers to offer free water leak repair services for income-qualified homeowners in Portland. Unfortunately, our funding  has run out for this fiscal year (July 2023–June 2024), but if you have a leak that needs repair, get on the waitlist. More funds will be available starting July 1, 2024.