Quick Answer:
If water still flows after you believe the main shutoff is closed, the shutoff you used may not be the actual service stop, it may be partially closed or failed internally, or there may be other valves that are open downstream. Start by locating and testing the curb stop and the water meter, then isolate downstream valves to narrow where the flow is coming from.
Why This Happens
There are a few common reasons a building keeps pressurized water even after the main valve appears closed:
- The curb stop or service valve at the street may still be open or only partly closed. That valve is the true supply control for the property.
- The meter or service line has a bypass, or a second feed, so shutting one valve doesn’t stop all flow.
- The shutoff itself may be damaged inside (corroded, broken stem, or a stuck gate) so the handle turns but the gate/ball doesn’t fully close. For details on valve types and failures, see gate valve vs ball valve.
- Only part of the system is isolated: for example, a single water heater or loop remains fed while the rest of the house is off. That situation is discussed in the article about main shutoff only stops hot water.
Step-by-Step What to Do
Step 1 — Stay calm and assess
Don’t panic. Turn off appliances that use water (dishwasher, washing machine) and close all faucets so you can test with a known off condition. Note whether flow is a trickle or a strong flow.
Step 2 — Verify the curb stop
Locate the curb stop or service shutoff at the property line or near the sidewalk. It is often in a small box or covered by a curb stop key plate.
- If you have the correct key, close the curb stop carefully and check fixtures inside. If the curb stop isn’t accessible or you’re unsure, call the utility or a plumber to avoid damaging it.
- Record whether closing the curb stop changes the flow; if it does, the problem is upstream of the meter.
Step 3 — Test meter movement
Use your water meter as a diagnostic tool:
- With all house faucets closed, watch the meter dial or digital indicator. If the meter moves, water is flowing somewhere in the house or there’s a leak on the service side.
- Close what you think is the main shutoff and watch the meter again. If the meter still turns, the valve you closed did not stop supply to the meter—either the valve didn’t seat or the curb stop/meter bypass is feeding water.
Step 4 — Isolate downstream valves
Work methodically through the house to find where the water is coming from:
- Close individual branch or isolation valves (hot and cold at fixtures, water heater shutoff, zone valves for irrigation) and recheck the meter after each closure.
- If closing a particular valve stops meter movement, you’ve isolated the fed section and can inspect that area for leaks or failed fixtures.
- If you cannot stop meter movement by closing internal isolation valves, the supply is still open at or before the meter and you need the curb stop or utility involvement.
Step 5 — If the valve handle turns but nothing changes
Do not assume the valve is working just because the handle stops. A handle stopping can mean a broken stem or a stuck internal part. If closing the handle does not change meter movement or fixture pressure, treat the valve as failed and proceed to get professional help or use the curb stop as your control point.
What Not to Do
- Do not assume valve is working just because handle stops — the handle may turn without sealing internally.
- Do not force or strike a stuck valve; you can break the stem or damage the service line.
- Do not dig around the meter or curb stop without calling local utility locating services first.
- Do not remove the meter or tamper with municipal equipment on your own; that may be illegal and could contaminate the supply.
When to Call a Professional
Call a licensed plumber or your water utility if any of the following apply:
- You cannot locate or operate the curb stop safely.
- The meter continues to move after local isolation attempts.
- There is heavy uncontrolled flow or flooding inside or outside the house.
- Valves are old, corroded, frozen, or clearly damaged when you inspect them.
- There are signs of contamination, sewage backup, or risk to structure or electrical systems.
Safety Notes
- Wear gloves and eye protection when working near valves or the meter; valves and fittings can be sharp or corroded.
- If flooding or major leaks occur, turn off electricity to affected areas before entering and avoid standing water near outlets.
- Do not attempt major repairs on the supply line yourself unless you are experienced and permitted to do so. Improper repairs can cause property damage and safety hazards.
- If you are unsure which valve controls your service, contact your water utility for guidance rather than guessing.
Common Homeowner Questions
- Why does the meter still turn when I close the main inside?
Because the interior valve may be damaged or there may be a curb stop, bypass, or secondary feed keeping the meter supplied. - Can I force a stuck valve closed?
No. Forcing it risks breaking the valve or the service line; call a plumber or the utility. - How quickly should I act if water keeps flowing?
Act immediately to prevent damage: isolate appliances, use the curb stop if safe, and call a professional if you cannot stop the flow.