Why this valve matters for slab leaks
A leak under the slab cannot be reached by any valve inside the house. Fixture stops under sinks and toilets only control those fixtures. The main shutoff, where the supply line from the meter enters the house, is what stops water going into the buried lines at all.
Between the moment you discover a fast leak and the moment a plumber arrives, that valve is how you limit damage. Closing it between planned uses is also how many homeowners live with a slow leak for a few days while they arrange repair.
Where to look on a typical Anaheim Hills house
Locations vary by builder and lot. Start at the front of the house, on the side facing the meter.
- Near a front hose bib, where the supply pipe rises out of the ground along the foundation
- On a garage wall, sometimes beside the water heater or a water softener
- Next to a pressure regulator, a bell-shaped fitting on the incoming line
- In a small access box in the ground between the meter and the house
- If you cannot find one, ask a plumber to locate and label it during any visit
Know your valve type
| Type | How it looks | How to close it |
|---|---|---|
| Ball valve | A lever handle in line with the pipe when open | Turn the lever a quarter turn so it sits across the pipe |
| Gate valve | A round wheel handle | Turn clockwise until it stops; it takes several turns |
| Meter valve | At the meter box, on the city side | Belongs to the utility; contact the city rather than forcing it |
Close it in an emergency
- Protect people first.Keep everyone away from water near outlets, cords or appliances.
- Close the main.Turn the lever a quarter turn or the wheel clockwise until it stops. Use steady hand pressure, not a cheater bar.
- Open a low faucet.Opening an outdoor or ground-floor faucet relieves pressure and shows you the water is off.
- Protect the water heater.Follow the heater's instructions; many people turn a gas heater to vacation or pilot, or switch off an electric heater, while the supply is off.
- Check the meter.With the main closed, the meter should stop. If it still moves, the leak may be between the meter and the house.
If the valve will not move
- IfA gate valve is stiffThenTry steady pressure in short attempts; do not force it hard enough to break the stem.
- IfThe valve leaks at the stem when turnedThenClose it anyway if water is surfacing indoors, then have it replaced.
- IfIt will not close at all and water is spreadingThenContact the city water utility about the meter-side valve and call a plumber.
- IfIt works but is old and stiffThenAsk a plumber to replace it with a quarter-turn ball valve during any repair.
Common questions
Should I test my shutoff before there is a problem?
Yes. Close it and reopen it once a year or so, gently, so you know it works and where it is.
Will closing the main hurt my water heater?
Briefly closing the supply is routine. For longer periods, follow the heater manufacturer's instructions, which often call for turning the burner or elements down or off.
Can I live with the main closed until the repair?
Many homeowners open it briefly for showers, cooking and flushing and close it again. It is inconvenient but limits water loss and damage.
General information for Anaheim Hills, not a quote or professional advice. In an emergency, call 911.