Emergencies
How to find and test your main water shutoff
Updated
Short answer
Look where the water line enters the house, usually through the basement or crawl space wall facing the street, next to the water meter. Test it once a year by closing it and confirming water stops at a faucet, so you know it works before a pipe bursts.
Where to look
Most Front Range homes have basements, and the main usually enters through the foundation wall closest to the street.
- Basement: on the street-side wall, often near the meter or behind an access panel in a finished wall
- Crawl space: near the foundation wall facing the street
- Slab homes: in a utility closet, near the water heater, or in the garage
- Newer homes: sometimes next to the water heater with a pressure reducing valve
How to close it
Gate valves have a round wheel; turn clockwise until it stops. Ball valves have a lever; a quarter turn so the handle crosses the pipe closes it. Old gate valves can break when forced, so turn slowly.
Test it once a year
Close the valve and open a faucet. If water keeps flowing, the valve isn't sealing. Ask a plumber to replace it with a quarter-turn ball valve before you need it in an emergency.
Replacing a bad shutoff valve
Old gate valves corrode and either won't close fully or snap when forced. A plumber replaces them with a full-port quarter-turn ball valve, which needs the water shut off at the curb stop by the utility or with a curb key.
While the water is off, it's a good time to add a pressure reducing valve if house pressure is high, and an expansion tank at the water heater if the system becomes closed.
- Quarter-turn ball valve replacement
- Pressure reducing valve check
- Expansion tank where required
When to call a plumber
Call if the problem keeps coming back, if water is reaching walls, ceilings or electrical areas, or if any step above involves gas, a torch or opening a sewer line. A licensed plumber handles burst pipe repair and will explain the cause before starting.
Questions
What if my main shutoff valve won't turn?
What is a curb stop?
This guide is general information for Colorado homeowners, not a substitute for an on-site diagnosis. Local codes vary; your plumber and building department have the final word.