Interactive Photo Diagram
Main Water Shutoff & Meter
Know where your main shutoff is before you need it. This is the single valve that stops all water to your house.
Reference checked: component relationships and terminology were reviewed against manufacturer documentation from A.Y. McDonald. This is original Classic Plumber educational artwork, not a manufacturer drawing.
Tap a numbered marker to learn what that part does.
Overview
Your main water shutoff is the single valve that stops all water to your house. It's usually near where the water line enters — in a basement, crawlspace, or utility room. The water meter, nearby, measures usage and has a leak indicator that can reveal hidden leaks. Knowing where both are before an emergency can save you thousands in water damage.
How It Works
Water enters from the city main through your service line, passes through the meter (which measures usage), and then through the main shutoff valve before branching to all fixtures in your home. The meter has a leak indicator — a small dial or triangle that spins even with very low flow. If everything in your house is off and the indicator is still moving, you have a hidden leak.
Key Components
Water Meter
Measures usage. Has a leak indicator (small dial) that moves even with very low flow.
Main Shutoff
Stops all water to the house. A lever-handle valve only needs a 1/4 turn.
Service Line Entry
Where the water pipe enters through the foundation wall.
Pressure Gauge Port
A faucet or port where you can check water pressure with a gauge.
Electrical Ground Bond
A ground wire clamped to the water pipe for electrical safety. Never remove.
Common Issues
Valve won't turn
Corroded gate valve. Don't force it — call a plumber to replace it before you need it.
Leaking at valve stem
Worn packing. Tighten the packing nut slightly with a wrench.
Meter spinning with everything off
Hidden leak. Check toilets first — a running toilet is the most common cause.
Can't find the shutoff
Look in basement, crawlspace, or near the water heater. It may be behind a panel.
Maintenance Tips
- Find your main shutoff today — don't wait for an emergency. Label it.
- Test the valve: turn it off and verify water stops at a faucet. If it won't turn, replace it.
- Do a meter leak test: turn off all water, check the leak indicator for 15 minutes.
- If you have a gate valve (round handle), consider upgrading to a ball valve (lever handle) for reliability.