How to find and use your water shutoff

When a pipe bursts or a toilet supply line lets go, every minute of running water adds to the damage. The fastest fix is knowing where your shutoff valves are before you need them.

Take ten minutes this week to find yours, make sure they work, and show everyone in the house where they are.

Two kinds of shutoff valves

The main shutoff stops water to the whole house. Use it for a burst pipe, a leak you can't trace, or any repair on the main lines.

Fixture shutoffs (sometimes called stop valves) stop water to one sink, toilet or appliance. Use them when one fixture leaks or needs a repair, so the rest of the house keeps its water.

Where the main shutoff usually is

Start where the main water line comes into the house. The City of Raleigh says that's usually a lower level, a crawl space or a utility closet, often close to the water meter or the main valve. [2]

From there, how the house was built is a good clue. WSSC Water, a large utility in Maryland, gives this rule of thumb: [1]

Basement homes: usually near the front foundation wall, where the water line comes in
Crawl space or slab homes without a basement: often near the water heater or under the kitchen sink

Some homes have the shutoff outside instead. Dallas Water Utilities says it's often near an outdoor faucet, close to the house. Homes with sprinklers may have it near the irrigation valves, often close to the property line, and in older homes it can be buried. [3]

There may also be valves in the water meter box near the street. In many systems, the valve on the street side of the meter belongs to the water utility, and the one on the house side is yours. [5] Utilities have different rules about the street-side valve. Fort Worth says you can close the water at the meter if you can't wait for a crew, as long as you don't damage the wires on the meter's radio transmitter. [4] Others ask you to call them, and some charge to turn water off and on. [1] Ask your utility before you need it.

If you rent, ask your landlord where the main shutoff is. [5]

How to turn off the main water

Find the handle type. Most main valves have either a round wheel handle or a straight lever handle. [1]
Close it. Turn a wheel handle clockwise. It may take two or more full turns. [1] Turn a lever handle a quarter turn, so it sits across the pipe instead of along it. [1] [3]
Don't force it. If the valve won't turn, stop and call a plumber. [5]
Check that it worked. Open a faucet on the highest floor. This lets out pressure and shows you whether the water has stopped. [1]
Turn it back on slowly. When the repair is done, close the faucets except that top-floor one, then open the valve partway. Once water runs from the top faucet, close it, wait for the pipes to quiet down, then open the valve all the way. [1]

If you can't stop the water yourself in an emergency, call your water utility. Charlotte Water takes emergency shutoff requests at 311 or 704-336-7600. [8] In Dallas, call 311. [3] Other cities have their own numbers: look yours up now and keep it handy.

A main valve that's rusted or crusted over may not close when you need it. See corroded water shutoff valve.

Shutoffs under sinks and behind toilets

Sinks. Look under the sink for one or two small valves on the pipes coming out of the wall. Shower and tub shutoffs, when a home has them, are often behind an access panel or in a closet behind the shower wall. [6] Turn each valve clockwise until it's snug, then open the faucet to make sure the water has stopped. [6] If there are no valves at the fixture, use the main shutoff. [6]

Toilets. The valve is usually on the wall or floor behind the toilet, below the tank. Turn it clockwise to close it, then flush to empty the tank. [7]

Water heater. Many water heaters have a valve on the cold water pipe going into the heater. Closing it stops water to the heater without shutting off the whole house.

Small fixture valves can stick, too. If one won't close or starts dripping after you use it, have it replaced. See sink and faucet repairs and tub, shower and toilet repairs.

Test and label your valves

Fort Worth Water suggests making sure your shutoff works now, before a pipe breaks. [4] Close the main valve slowly, then open the top-floor faucet to confirm the water is off. [1] If you live in a building with several units, don't do this test. You could shut off a neighbor's water. [5]

Then hang a tag on the main valve so it's easy to spot in an emergency, and make sure everyone in the home knows where it is. [4] [5]

Simple plumbing upkeep

Check for hidden leaks. Read your water meter, wait two hours without using any water, then read it again. If the number changed, you probably have a leak. [9]

Test your toilets. Put a few drops of food coloring in the toilet tank. If color shows up in the bowl within 10 minutes, the toilet is leaking. Flush right after so the dye doesn't stain. [9]

Fix drips. A faucet that drips once a second can waste more than 3,000 gallons a year. [9] Shut off the fixture's water before you take a faucet apart. [9]

Check hose connections. Run the garden hose and look at the spigot connection. If it leaks, a new washer and a tighter connection usually fix it. [9]

Watch your water pressure. Pressure that's too high wears out valves, faucets and the water heater. HomeCloud reports flag pressure over 80 PSI (pounds per square inch). See high water pressure and pipe and drain repairs.

Flushing a tank water heater

Sediment settles at the bottom of a tank water heater over time. A. O. Smith says most tank heaters need flushing at least once a year, and more often with hard water. [10] Tankless heaters aren't flushed this way. Many need descaling instead, following the maker's manual. [10]

A. O. Smith's basic steps for a tank heater: [10]

Turn off the power to an electric heater, or turn off the gas to a gas heater following its manual.
Wait a few hours so the water cools. This lowers the risk of burns.
Attach a hose to the drain valve at the bottom and run it to a drain or outside.
Open the drain valve and let water run until no more sediment comes out.
Close the drain valve and refill the tank completely before turning the power or gas back on. Heating an empty tank can burn out an electric element.

Wear gloves and eye protection. [10] If your heater is gas and you aren't comfortable with its gas controls, or the drain valve won't open or close properly, have a plumber do it.

A. O. Smith also suggests checking the temperature and pressure relief valve once a year by lifting its lever a few times, and having a professional check it every five years. [10] If the valve keeps dripping afterward, or you see water coming from its pipe on its own, call a plumber. See TPR valve discharge and water heater repairs.

If you're thinking about a new heater, see tank vs. tankless water heaters. To learn what your pipes are made of while you're looking at the valves, see what kind of pipes do I have?

HomeCloud is a licensed general contractor that evaluates homes, then prices and does repairs, including shutoff valve and water heater work.