Find your main water shutoff before you need it at 2 AM

What to do, in order

1. Locate the house-side main: usually where the water enters — basement wall facing the street, crawlspace, garage, or a slab-home's curb box at the front yard/sidewalk.
2. Turn it fully clockwise. Old gate valves can seize — if it won't budge, don't force it: your curb box (needs a meter key, $15) is the backup.
3. Tag it: bright tag, family members know. If it's a lever ball valve, quarterly quarter-turns keep it functional.
4. Test fixtures after shutoff: residual water in lines drains briefly then stops. If it keeps running, the valve's not sealing — plumber visit scheduled on your terms, not during a flood.
5. While you're at it: tag the water heater's gas valve/shutoff and the electrical sub-breakers for HVAC.

Red flags — stop and call a pro

• A seized main valve with a known slow leak anywhere in the house — get the valve replaced before the emergency makes the decision for you
• Curb box that's rusted shut or paved over — utility can service it; don't wait for the flood

Prevention

Quarterly exercise of shutoff valves (they corrode in position), and a meter key hanging visibly if your curb box is the realistic shutoff path.

This guide is maintained by the ee.ltd editorial team — reviewed for 2026. Browse all home repair guides or compare plumbing costs.

Related guides

• Water heater leaking from the bottom: what to do right now
• Sudden low water pressure in the whole house: diagnosis
• Clogged drain: when to plunge, snake, or call a pro
• Toilet keeps running: the 3 parts to check

What this repair typically costs

• Water heater replacement cost guide
• Water heater repair cost guide
• Toilet installation cost guide
• Faucet replacement cost guide