How to Shut Off Water in Your House: Main Shutoff and Individual Valves
Knowing where your main water shutoff is — and that it actually works — is the most important plumbing knowledge a homeowner can have. A burst pipe gives you about 60 seconds before serious water damage begins. Here's everything you need to know before that happens.
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Finding your main shutoff valve
There are two main shutoff locations in most homes:
- Inside shutoff: Located where the water supply enters the house — typically in the basement, crawlspace, utility room, or under a first-floor bathroom. Usually a gate valve (round wheel handle) or ball valve (lever handle). This is the one you want to know and use.
- Street shutoff (curb stop): In the ground near the street or curb, inside a concrete box with a metal lid. Requires a special key tool to operate. This is the backup if the inside shutoff fails or doesn't exist.
If you've never found your inside shutoff, walk the perimeter of your house at the point where it meets the street. The water service line comes from the street and enters the house at foundation level — the shutoff valve is typically within a few feet of where the pipe enters.
Types of shutoff valves
Ball valve (lever handle)
The lever is parallel to the pipe when open, perpendicular when closed. A quarter-turn closes it. Fast, reliable, and the preferred type in modern homes. If your shutoff is a ball valve, test it once per year — turn it fully off and back on to prevent seizing.
Gate valve (round wheel)
Requires multiple full turns to open or close. Older and less reliable — the internal gate can corrode or break, especially if the valve hasn't been operated in years. If your main shutoff is a gate valve that looks original to the house, consider having a plumber replace it with a ball valve ($150–300). You don't want to discover it doesn't close during an emergency.
Under-sink and toilet shutoffs
Every sink and toilet has an individual shutoff valve (the oval knob under the sink or behind the toilet). These let you shut off water to one fixture without cutting the whole house. Test them all annually — turn each one fully clockwise until it stops, then back counterclockwise. If any resist or leak when operated, replace them ($15–30 each, easy DIY).
Water heater shutoff
There's a cold water supply shutoff on the pipe entering the top of the water heater (usually a gate or ball valve). Shut this off first during a water heater leak — it stops water from continuing to fill a leaking tank. Know where it is.
What to do if the main shutoff won't close
- Gate valve partially stuck: Apply penetrating oil (WD-40 or PB Blaster) to the stem, wait 10 minutes, try again with firm pressure. Do not force it — a broken valve stem leaves you with no shutoff at all.
- Gate valve spins freely but doesn't shut off water: The internal gate has broken off. The valve is non-functional. Use the street shutoff (curb stop) and call a plumber to replace the main valve.
- No inside shutoff at all: Some older homes have only the street shutoff. Confirm its location and get a curb key tool ($15–25) — you need to be able to operate it yourself in an emergency.
- You can't find it: Look in the basement or crawlspace along the wall facing the street. Check inside a utility closet. Check behind the water meter if it's in the house. If still not found, ask a plumber to locate and tag it during any service visit.
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