How to Find and Fix Household Water Leaks

Leaks are the most common home repair that pays for itself. A worn toilet flapper or a dripping faucet costs a few dollars to fix but can waste thousands of gallons a year. This guide follows EPA’s WaterSense program, which runs Fix a Leak Week every March, to help you find leaks and fix the common ones.

How do you know if you have a water leak?

• Meter test. Check your water meter before and after a two-hour period when no water is being used. If the meter changes at all, you probably have a leak.
• Winter bill check. Look at your water use in a cold month such as January or February. WaterSense says that if a family of four uses more than 12,000 gallons a month, there could be serious leaks.
• Look and listen. Check faucet gaskets and pipe fittings for water on the outside of pipes, and listen for a toilet that refills on its own.

How do you test and fix a leaking toilet?

Put a few drops of food coloring in the toilet tank. If any color shows up in the bowl after 10 minutes, you have a leak. Flush right after the test so the dye doesn’t stain the tank.

The usual cause is the flapper, the rubber seal that holds water in the tank. WaterSense says to check flappers periodically and replace them at least every five years. To buy the right one, bring the old flapper (or a photo) to the hardware store, note its width and whether it has a foam float, or check your owner’s manual or the maker’s website. Replacing a flapper usually takes a few minutes: shut off the water at the valve behind the toilet, flush to empty the tank, unhook the old flapper and chain, hook on the new one, and adjust the chain so it has a little slack.

How do you fix a dripping faucet?

WaterSense says a faucet dripping once per second can waste more than 3,000 gallons a year, and that old, worn washers and gaskets frequently cause faucet leaks. Turn off the water under the sink, plug the drain so small parts can’t fall in, take the handle apart following the maker’s instructions, and replace the worn washer, O-ring or cartridge with a matching part. If parts are hard to find or the faucet is corroded, replacing the faucet may be simpler; look for the WaterSense label on new faucets.

What about a leaky showerhead?

A showerhead leaking 10 drips a minute wastes more than 500 gallons a year, according to WaterSense. Many can be fixed by making a tight connection between the showerhead and the pipe stem with pipe tape (also called Teflon tape), and by replacing the washer or O-ring inside the showerhead. For a shower valve that drips when the water is off, WaterSense suggests an experienced handyperson or licensed plumber.

How do you check for leaks outdoors?

• Garden hoses: if a hose leaks at the spigot while running, replace the rubber or nylon hose washer and tighten the connection with pipe tape and a wrench.
• Sprinkler systems: check an in-ground system each spring for damage from frost or freezing. WaterSense says a leak 1/32 of an inch across (about the thickness of a dime) can waste about 6,300 gallons a month. It suggests hiring an irrigation professional certified by a WaterSense labeled program if you need help.

Outdoor watering is its own topic; see our lawn watering guide.

When should you call a plumber?

Call a licensed plumber when the meter test shows a leak you can’t find, when there is water in walls, ceilings or under floors, when a main or supply line leaks, when a shower valve drips with the water off, or when you aren’t comfortable shutting off and working on the water supply. Know where your home’s main water shutoff is before you need it. Our hiring guide covers bids and contracts.

When does it make sense to replace a fixture?

If repairs don’t stop the leak, WaterSense suggests replacing the fixture and looking for the WaterSense label on new toilets, faucets and showerheads. A plumbing professional can help with installation.

Leak checks are part of our monthly and seasonal home maintenance checklist.