When a pipe bursts, the first two minutes matter more than anything a plumber does later. Find your main shutoff now, while nothing is leaking, and make sure it actually turns.
The short version
- Look where the water line enters the house: usually the basement or crawl-space wall that faces the street.
- A round handle (gate valve) turns clockwise until it stops. A lever handle (ball valve) turns a quarter turn, so the lever sits crosswise to the pipe.
- Open the lowest faucet in the house to drain the pressure off.
- If the valve won't move or won't stop the water, call your water provider's emergency line. Don't force it.
Where to look in a Denver-area house
The main shutoff sits where the water service pipe comes through the foundation, and it's almost always on the side of the house closest to the street.
- Houses with a basement: on the front foundation wall, often low, sometimes behind a finished wall with an access panel, a shelf, or a stack of boxes. In older Denver houses the water meter may be inside the basement too, with a valve on one or both sides of it.
- Crawl-space houses: just inside the crawl-space access, near where the line comes in. A lot of ranches in the older suburbs are built this way.
- Slab homes and newer townhomes: in the utility closet or garage, near the water heater or where the line comes up through the floor. Sometimes it's under the stairs.
- Condos and apartments: there's often a shutoff for your unit in a utility closet or behind an access panel. If there isn't, the building controls it, so find out from the HOA or manager who has the key.
Follow the cold water line backward from the water heater or the kitchen sink if you can't find it. It leads to where the water comes in.
Two kinds of valves
Gate valve (round wheel handle): turn it clockwise, several full turns, until it stops. These are common in older houses. They're also the ones that seize: if it won't turn with firm hand pressure, stop. Forcing an old gate valve can snap the stem and leave it stuck open, or start a new leak at the stem.
Ball valve (lever handle): a quarter turn. When the lever is in line with the pipe, it's open. When it's crosswise to the pipe, it's off. Ball valves are much more reliable, and they're what we install when we replace an old main shutoff.
The curb stop and the meter pit
Outside, usually near the sidewalk or property line, there's another valve called the curb stop, sometimes inside a meter pit. In most cities it's meant to be operated by the water utility with a special key. If your inside valve fails during an emergency, call your water provider's emergency number. They can shut the water off at the curb.
After the water is off
- Open the lowest faucet (basement sink, laundry tub, or an outside faucet in warm weather) to drain the pressure off the lines.
- If the water will be off for a while, or you're draining the system, turn an electric water heater off at the breaker and set a gas water heater to pilot or vacation, so it isn't heating a draining tank.
- Take photos of any damage before cleanup, for insurance.
Test it once a year
Turn the main off and back on once a year, maybe when you change the smoke detector batteries. If it's stiff, won't close all the way, or drips from the stem when you move it, have it replaced now. It's a small job on a normal day and a very expensive problem on the day a pipe bursts. We replace seized shutoff valves →
Smaller shutoffs worth knowing
- Under sinks and behind toilets: small valves (angle stops) that shut off just that fixture.
- Water heater: a valve on the cold-water inlet at the top of the tank.
- Irrigation: a separate valve for the sprinkler system, usually in the basement near the main or in a valve box outside. You'll need it for your sprinkler blowout.