Where is Your Main Water Shut-Off Valve:

A 10-Minute Homeowner Guide: Estimated read time: 6 - 8 minutes

In a leak, every second counts. Know where your house/main shut-off valve is (usually where the water line enters the home) and how to turn it off. Learn your street/curb shut-off rules, label both, and run a one-minute drill with your household. Add a couple of low-cost prevention upgrades - leak alarms and under-sink protection—to minimize damage.

Why this matters

A burst supply line, failed washing machine hose, or split ice-maker tube can release dozens of gallons of water before anyone notices. Quick action - walking straight to the main valve and turning it off - can be the difference between a quick cleanup and weeks of repairs.

Your goal today:

Locate the main shut-off.

Verify it works.

Label it and share its location with everyone in the home.

Know the back-up (street/curb) valve procedure in your area.

Two types of shut-off valves (you may have both)

House/Main Shut-Off (Primary):

The fastest way to stop water during an indoor leak. Located where the water supply line enters your home.

Street/Curb Shut-Off (Backup):

In the meter box near the sidewalk or street. Often requires a curb key (a long T-handle). In many municipalities, only the utility should operate this valve - know your local rules and save their 24/7 number.

Where to find the house/main valve

Basement homes: Along the front foundation wall (street-facing). Look for the pipe entering from outside, often near a pressure regulator or meter.

Slab / warm-climate homes: In the garage, utility/laundry room, or a small ground box just outside where the line enters.

Crawlspace homes: On the interior side of the foundation near the entry point; sometimes there’s a secondary valve in an indoor utility area.

Townhomes/condos: Inside a mechanical closet, behind an access panel, or in a shared utility room. Management can provide exact locations.

Well systems: Near the pressure tank; confirm which valve isolates the house vs. the well line.

What it looks like:

Ball valve (preferred): Lever handle. Parallel with the pipe = ON. Quarter-turn perpendicular = OFF.

Gate/stop valve: Round wheel. Turn clockwise to close. Older units can be stiff - do not force them.

Quick functionality test (do this once)

Turn the house/main valve OFF.

Open a nearby cold faucet - flow should slow to a trickle and stop.

Turn the valve ON again and let air sputter out.

If the valve sticks, leaks, or won’t close fully, stop and call a licensed plumber.

Pro tip: Exercise the valve twice a year (off/on) to prevent seizing.

Label it - and share the location

Attach a bright tag that reads “MAIN WATER — OFF →” with an arrow showing direction to close.

Keep the path to the valve clear.

Snap a photo and share it in your family or roommate group chat.

Printable tag text (copy/paste to a card):

MAIN WATER SHUT-OFF

Turn handle ¼-turn so it is perpendicular to the pipe to CLOSE.

Open a cold faucet to confirm flow stops.

The street/curb shut-off (backup plan)

Open the meter box carefully (lids can be heavy; gloves recommended). Inside is the water meter and usually a curb stop valve.

Know the policy: Many utilities prefer or require that only utility personnel operate this valve. Add your water utility’s 24/7 emergency number to your contacts today.

If homeowner operation is allowed: You’ll need a curb key. Operation is often a quarter-turn to set the slot perpendicular to the pipe for OFF. You may need a special tool that could be found at your local hardware store.

Fast controls that buy time

Fixture shut-offs: Small valves under sinks and toilets isolate a single fixture so you don’t have to shut water to the whole house.

Water heater safety: If your main will be off for more than a brief repair, set the water heater to vacation/low (gas) or off (electric) so it’s not trying to heat without incoming water. No need to drain the system unless directed by a professional.

Low-cost prevention that actually helps

Battery leak alarms: Place on the floor of sink bases, behind refrigerators and washing machines. They alert early when moisture is detected.

Under-sink protection: A water-resistant mat or tray in kitchen and bath sink cabinets helps keep small drips contained and easier to spot - an inexpensive layer of insurance.

(If you’re outfitting multiple bathrooms or kitchens, organize by size before you shop to make installation faster.)

Maintenance & upgrade checklist

Exercise the house valve every 6 months.

Replace unreliable or corroded gate valves with full-port ball valves.

Ask a plumber about a pressure-reducing valve (PRV) if your area runs high pressure.

Keep meter boxes and exterior shut-off boxes visible and accessible (not buried under mulch).

For multi-unit buildings or rentals, keep written instructions and locations on hand. Share with all family members and friends and see the example how water damage adds up.