How to Detect Water Leaks

Causes of Leaks

A small leak, about the size of the head of a pin, dripping at one drop per second can add up to 7 gallons of water per day. A large leak, the kind most often found in toilets, can waste 200 gallons of water or more per day! Check out the following when you suspect a leak:


Check faucets in the bathroom and kitchen periodically. Most often, worn washers are the cause of dripping faucets.

Sprinkler Systems

Sprinkler Systems Broken sprinkler heads or damaged underground pipes are common sources of sprinkler system leaks. Watch your system run at least once per month to spot problems early.


Check toilets for leaks often. The most common causes of a leaking toilet are

  1. Float device set too high, which causes water to run into the overflow tube
  2. A warped or cracked flapper

Toilet leak kits are available. The kit contains tablets that are dropped into the toilet tank. After the tablets are placed in the tank wait 15 minutes, then check the toilet bowl. (Remember, don't flush during this time.) If the water in the bowl changes color, you have a leak!

Don't forget to use your water meter to detect leaks.

How to Check for a Water Leak

Finding water leaks can save you water, which means saving money on water and sewer bills. Follow these easy steps to determine if you have a leak in domestic or a sprinkler irrigation system.

  • Step 1. Turn all water-using appliances off so that no water is being used. This means turning off all water inside and outside the house including showers, sinks, washing machines and any appliance that uses water.
    • If you have a sprinkler irrigation system, turn off the controller and manually shut off the two valves at the double check valve assembly to isolate the irrigation system.
  • Step 2. Locate Meter Box and shine a flashlight on the photoelectric eye (look for flashlight symbol) to activate the screen. The screen eventually will begin to flash between "Reading" and "Rate". This is usually located close to the meter box. The "Rate" is the amount of water (in gal/min) that is passing through the meter at that moment. The "Rate" can be used for leak detection; if all water in the building is shut off and a rate is observed this means that water is flowing through the meter. Since all water is shut off there must be a leak somewhere.
  • Step 3. Locate the main shut off valve to the house.
  • Step 4. Turn off the valve.
  • Step 5. Turn on a faucet inside the house to test. If water still flows from the faucet after several seconds, the shut off valve is not working. If no water flows through the faucet, the shut off valve is not working. Return to the meter.
  • Step 6. To check a toilet for leak: flush the toilet and while the reservoir is still filling, add 2 or 3 drops of food coloring to the water in the reservoir. Wait 15 to 30 minutes. If the water in the bowl changes colors, the flapper valve needs to be replaced.