Checking For Leaks

water meter diagram

Checking for Leaks

The red pointer is what is referred to as the leak indicator and will move in a counter-clockwise direction when water is moving through the meter. On the Sensus meter, the small black triangle located above the numbers is the leak indicator and will move in a clockwise motion when water is moving through the meter.
With all the water turned off in the house, there should be no movement of the pointers or the dials on any of the meters. If you have turned off all the taps in the house, and the meter appears to be turning, you may have a leak.

Slow Drip

Slow drips of water can add up quickly. A toilet that "keeps running" after you flush or a sink that drips after it is turned off can waste thousands of gallons of water a year. If the drip is hot water, you are paying for wasted energy too. Fix leaks as soon as you find them.

A "Running" Toilet Leak

One of the most costly household wastes of water is a leaky toilet. According to the American Water Works Association, toilets account for 45% of all indoor water use in a typical residence.

Toilet leaks can range from small to large, constant to random, or from being heard or silent. They all cause wasted water. Depending on the water pressure to your house, a running toilet can leak 1 gallon of water per minute which adds up to 1,440 gallons per day. This is almost 2 units of water a day and if left undiscovered, a running toilet can waste almost 60 units of water a month.

Fortunately, most toilet leaks are relatively easy to fix. In a properly functioning toilet, no water should move from the tank to the bowl, unless the toilet is being flushed. A leaking toilet loses water from the tank to the bowl without being flushed. A toilet can also waste water due to an improperly adjusted or broken fill (ballcock) valve causing water to enter the tank and flow into the overflow tube.

Faulty Valve
Most toilet leaks are caused by a faulty valve (also known as "flush valve ball" or "tank stopper"). Most hardware, plumbing and home improvement stores supply flappers.

How to check for a leaky toilet flush valve (flapper):
  1. Carefully remove and set aside the tank lid. (Don't worry, this water is clean until it enters the bowl.)
  2. Add some food coloring or a dye tablet to turn the water a different color.
  3. Put the tank lid back on.
  4. Wait 15 minutes and do not flush.
  5. If dye appears in the toilet bowl, the flapper valve in your toilet is leaking and should be replaced. The second most-common type of toilet leak is caused by an improperly adjusted or broken fill (ball cock) valve. If the float is set too high or if the shut-off valve fails to close completely, water will continue to enter the tank and flow into the overflow tube.
This type of leak can be seen simply by taking the tank top off and observing if water is flowing into the overflow tube once the tank is full.

A Leaking Faucet

A leaking faucet is frequently the result of a bad rubber washer. The washer on a sink is typically located under the handle. A washer is relatively easy to replace with the right tools. It does require shutting off the water under the sink, and removing the handle.

Quick Facts

  • A leaky faucet that drips at the rate of one drip per second can use more than 3,000 gallons per year!
  • A showerhead leaking at 10 drips per minute can use more than 500 gallons of water per year.

Leaky Automatic (in-ground) Irrigation Systems & Spigots

An irrigation system should be checked each spring before use to make sure it was not damaged by frost or freezing. An irrigation system with pressure set at 60 pounds per square inch that has a leak 1/32nd of an inch in diameter (about the thickness of a dime) can waste about 6,300 gallons of water per month!

Check your garden hose for leaks at its connection to the spigot. If it leaks while you run your hose, replace the nylon or rubber hose washer and ensure a tight connection to the spigot using pipe tape and a wrench.

How Much Water Is Lost?

Small household leaks left unrepaired can lead to big trouble over time.

Leak Source

Typical Leakage

Gallons/Day Used

Gallons/Month Used

Units/Month Used

Running toilet

1 gallon/minute




Leaking faucet

1 drip/second




Leaking showerhead

10 drips/minute




In-ground irrigation

1/32" in diameter (about the thickness of a dime)




Overflow tube in toilet tank

1/4" in diameter




A garden hose left running or a missing sprinkler head

1/2" in diameter




Water is billed in units where 1 unit = 748 gallons of water.