In a typical Fullerton slab home, the main house shutoff is on an exterior wall where the supply line rises out of the ground, often near a hose bib, in the garage or beside the water heater. The water heater has its own cold inlet valve. Most sinks and toilets have small angle stops, and irrigation usually has a separate valve near the front of the house or at the backflow device.
Spend twenty minutes finding each one, write it down below, and you will not be guessing during a leak.
Your valve table
| Valve | What it shuts off | Where it is | Tested? (date) |
|---|---|---|---|
| Main house shutoff | All water inside the house | ____________ | ____ |
| Water heater cold inlet | Water to the heater and the hot side | ____________ | ____ |
| Irrigation valve | Sprinklers and drip lines | ____________ | ____ |
| Kitchen sink stops | Kitchen faucet only | Under sink | ____ |
| Bathroom sink stops | That sink only | Under each sink | ____ |
| Toilet stops | That toilet only | Behind each toilet | ____ |
| Washing machine valves | Washer only | Behind washer | ____ |
| Meter (utility side) | Not for homeowner use | Meter box at street | Do not operate |
Testing a valve safely
- Turn slowly.Turn the handle clockwise to close. Gate valves with round wheels take several turns; ball valves with a lever take a quarter turn.
- Do not force it.If a valve will not move with reasonable hand pressure, stop. Forcing an old valve can break the stem or start a new leak.
- Check it worked.Open a faucet the valve should control. Water should stop or slow to a trickle.
- Reopen.Turn it back fully open, then a slight turn back on gate valves to keep them from sticking.
- Record.Write the date and result in the table.
Which valve to close in a slab leak
- IfWater is surfacing through the floorThenClose the main house shutoff.
- IfA warm floor suggests the hot line, nothing surfacingThenClose the water heater cold inlet; cold water keeps working.
- IfWater near outlets or electrical equipmentThenClose the main, keep people away and turn off that circuit from a dry spot.
- IfThe main will not closeThenContact the City of Fullerton's water utility about shutting water at the meter; do not force the meter valve yourself.
Make the map useful
- Tape a copy inside a kitchen cabinet and another in the garage.
- Tag the main shutoff and heater inlet with a bright label.
- Keep a meter key or flat screwdriver near the front door.
- Show every adult in the house where the main shutoff is.
- Note any stuck valve and ask a plumber to replace it before you need it.
Common questions
My house has no main shutoff I can find. What now?
Some older homes have a hard-to-find or buried valve. A plumber can locate it or install an accessible one.
Is closing the main bad for the water heater?
Short closures are normal. Avoid running hot water while the main is off, and do not adjust the heater's gas or power.
How often should I test valves?
Once or twice a year is a common habit, gently and without forcing.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.