How to Shut Off Water to Your House in an Emergency

When a pipe bursts or a water heater starts leaking, every minute counts. A burst pipe can release hundreds of gallons of water in just a few hours, soaking floors, walls, and everything in its path.

Knowing how to shut off water to your house is one of the most important skills a homeowner can have. In this guide, our Los Angeles plumbers explain where to find your main water shut off valve, how to turn it off safely, how to shut off water to individual fixtures, and what to do once the water is off.

Tip: Do not wait for an emergency to learn this. Take 10 minutes today to find your valve and test it.

When Should You Shut Off Water to Your House?

Turn off the main water supply right away if you notice:

• A burst or leaking pipe
• Water leaking from the ceiling or walls
• A leaking or failed water heater
• An overflowing toilet that will not stop
• Pipe damage after an earthquake
• Before major plumbing repairs or fixture replacements
• Before leaving home for an extended trip

If the leak is limited to one fixture, such as a toilet or sink, you can often shut off just that fixture using its local valve. We cover that further below.

How to Find Your Main Water Shut Off Valve

Most homes have two places where you can stop the water: the main shut off valve at the house and the meter valve at the street.

Common Main Shut Off Locations in Los Angeles Homes

Because most Southern California homes are built on concrete slabs without basements, the main valve is often outside. Check these spots in order:

1. Outside the front of the house, where the water line comes up from the ground and enters the home. It is often near a hose bib and may sit next to a bell-shaped pressure regulator.
2. In the garage, especially in newer homes, on the wall closest to the street.
3. Near the water heater, in some older homes and condos.
4. Under the kitchen sink or in a utility closet, in some condos and apartments.
5. In a basement or crawl space, in older homes that have them, on the wall facing the street.

A good rule of thumb is to look on the side of the house that faces the water meter. If you still cannot find it, check your home inspection report, which usually notes the valve location.

Water Main Shut Off Valve at the Street (Meter Box)

Your water meter is usually in a concrete or plastic box near the curb or sidewalk. Inside, there is a shut off valve on the city side of the meter.

This water meter shut off valve belongs to the utility. In Los Angeles, it is typically managed by LADWP or your local water provider. Use it only in a true emergency when you cannot find or operate the house valve, and contact your water utility if you need help.

Water Main Shut Off Valve Types

How you turn off the valve depends on which type you have.

Remember the phrase “righty tighty, lefty loosey.” Turning clockwise closes the valve, and turning counterclockwise opens it.

How to Shut Off Water to Your House: Step by Step

1. Find the main shut off valve. Use the locations listed above.
2. Turn the valve to the closed position. For a ball valve, rotate the lever a quarter turn until it is perpendicular to the pipe. For a gate valve, turn the wheel clockwise until it stops. Do not force it.
3. Open a faucet at the lowest point in the house. An outdoor hose bib or a ground-floor tub works well. This drains the water left in the pipes and relieves pressure.
4. Open a faucet on the highest floor. This lets air into the system so the lines drain faster.
5. Turn off the water heater. Set a gas unit to “pilot” or “vacation” mode, or switch off the breaker for an electric unit. A heater that runs without water can be damaged.
6. Confirm the water is off. Check that no water is flowing from any faucet and that the water meter’s leak indicator has stopped moving.

What If the Valve Is Stuck?

Older gate valves are notorious for seizing up, especially in homes with hard water like much of Los Angeles. If your valve will not turn:

• Apply penetrating oil around the valve stem and wait 10 to 15 minutes.
• Use a valve wheel key or water shut off tool for extra leverage.
• Turn slowly and steadily. Forcing a corroded valve can snap the stem or cause a new leak.

If the valve still will not move, go to the meter valve at the street or call a plumber. A stuck or leaking main valve should be replaced. Most plumbers recommend upgrading old gate valves to quarter-turn ball valves, which are faster to close and much less likely to fail.

How to Shut Off Water to Individual Fixtures

You do not always need to cut water to the whole house. Most fixtures have their own shut off valves, called stop valves or angle stops.

Toilet Water Shut Off Valve

Look on the wall or floor behind and below the toilet. Turn the oval handle clockwise until it stops. This is the first move if a toilet is overflowing or leaking. For repair steps, see our guide on how to fix a leaking toilet.

Sink Shut Off Valves

Open the cabinet under the sink. You will usually see two valves: one for hot and one for cold. Turn both clockwise to stop the flow. These valves also make it easy to replace a faucet, as explained in our guide on how to install plumbing fixtures.

Water Heater Shut Off Valve

The water heater shut off valve is on the cold-water supply line at the top of the tank. Turning it off stops new water from entering the heater. If your tank is leaking, shut this valve, turn off the power or gas, and read our guide on how to repair a leaking hot water heater.

Washing Machine and Dishwasher Valves

Washing machines have hot and cold valves on the wall behind the unit. Dishwashers usually connect to a valve under the kitchen sink.

What to Do After You Shut Off the Water

Stopping the water is step one. Here is what comes next:

1. Turn off electricity near the water. If water is close to outlets, appliances, or your electrical panel, switch off power to those areas. Never stand in water to reach the panel.
2. Remove standing water. Use towels, mops, and a wet vacuum to limit damage.
3. Document the damage. Take photos and videos for your insurance claim.
4. Find the source of the leak. If water is coming through the ceiling, our guide on water leaking from the ceiling explains what to check. Warm floors or a spinning meter with everything off may point to a slab leak, which we cover in how to detect a water leak under a slab.
5. Call a licensed plumber. Most burst pipes and failed valves need professional repair before the water can be safely turned back on.

How to Turn the Water Back On Safely

Turning water back on too fast can cause water hammer and stress your pipes.

1. Close all the faucets you opened earlier.
2. Open the main valve slowly, a little at a time.
3. Open each faucet one at a time to let air escape. Expect some sputtering.
4. Check for leaks at the repair site and under sinks.
5. Turn the water heater back on once the tank is full.

If you notice weak flow afterward, debris may have been knocked loose into aerators. See our guide to low water pressure in the house for quick fixes.

Earthquake Preparedness: Know Your Shut Offs

In Los Angeles, earthquakes are a real risk to plumbing. Ground movement can crack pipes, break water heater connections, and damage gas lines.

Make a simple plan:

• Label your main water shut off valve with a tag so anyone in the family can find it.
• Keep a water shut off tool and an adjustable wrench in an easy-to-reach spot.
• Make sure your water heater is properly strapped, as required by the California code. Our Los Angeles plumbing code guide explains this rule.
• Know where your gas meter shut off is, too. If you smell gas after a quake, follow our guide on how to detect a gas leak.

Should You Install an Automatic Water Shut Off Valve?

An automatic water shut off valve installs on your main line and closes on its own when sensors detect a leak or unusual flow. Many models connect to a smartphone app, so you can shut off water remotely.

These systems are worth considering if you travel often, own a rental property, or have had water damage before. Some insurance companies also offer discounts for homes with leak detection systems.

Frequently Asked Questions

Where is the water shut off valve in a house? In most Los Angeles homes, the main valve is outside near the front of the house, where the water line enters. It may also be in the garage, near the water heater, or in a utility closet.

Can I shut off water at the meter myself? In an emergency, yes, using a water shut off tool or wrench. The meter valve belongs to the utility, so contact them for non-emergency situations.

How long can you leave the water shut off? You can leave it off as long as needed. Just turn off the water heater first and drain the lines if you will be away for a long time.

Why won’t my water shut off valve close all the way? Old gate valves often wear out or build up minerals, so they no longer seal completely. A plumber can replace it with a reliable ball valve.

Should I turn off the water when I go on vacation? Yes. Shutting off the main valve while you are away is one of the easiest ways to prevent major water damage.

Need Help With a Leak or a Stuck Valve?

Knowing how to shut off water to your house can save you thousands of dollars in water damage. Find your main valve today, test it, and make sure everyone in your home knows where it is.

If your valve is stuck, leaking, or you are dealing with a burst pipe right now, Hi Tech Plumbing Services Inc is ready to help. Our emergency plumbers in Los Angeles respond quickly to stop leaks, replace failed shut off valves, and repair damaged pipes. You can also schedule a non-emergency visit to upgrade your main valve before you ever need it.