Main water shut off valve location: how to find it in an older New Jersey home

Where the main shut-off valve usually is

The water comes into the house from the street in one pipe, and the main shut-off is on that pipe, close to where it comes through the wall or floor.

• In a house with a basement, look on the wall that faces the street, usually low down. The pipe comes through the foundation and goes to the water meter. There is normally a valve just before the meter and another just after it.
• In a house without a basement, look near the water heater, in a utility closet, under the kitchen sink, or in a crawl space near the front of the house.
• In a two- or three-family house, there may be one main shut-off for the building and separate valves for each unit, often near each unit's water heater. Find both.
• In a house on a well, common in northern Passaic County, the main shut-off is on the pipe after the pressure tank. Switching off the well pump's breaker also stops the supply.

There is also a valve under the sidewalk or at the property line, called the curb stop. It belongs to the water utility, needs a special key, and is not the valve to use in an emergency.

Gate valve or ball valve: what you are looking at

Older homes usually have a gate valve: a round handle, like a small wheel, that you turn clockwise several times to close. Gate valves are the ones that seize. After decades without being touched, the handle may not turn at all, or it may turn without closing because the gate inside has broken off its stem.

Newer valves are usually ball valves: a straight lever that closes with a quarter turn. When the lever runs across the pipe, the water is off. Ball valves are far more reliable, which is why they are what we fit when a main valve is replaced.

How to test your main shut-off

Do this once a year, when nothing is wrong.

1. 1Open a cold tap on the lowest floor and let it run.
2. 2Turn the main valve clockwise, gently. A gate valve should turn smoothly for several turns; a ball valve lever should move a quarter turn.
3. 3Watch the running tap. Within a minute or so, the flow should stop completely.
4. 4Open the valve again fully, then turn it back a quarter turn so it does not stick in the open position.

If the tap keeps running with the valve closed, the valve is not sealing. If the handle will not turn with firm hand pressure, stop. Forcing an old gate valve is how you snap the stem or start a leak at the packing, which turns a test into an emergency.

What to do in an emergency

1. 1Turn off the main shut-off.
2. 2Open the lowest tap in the house to drain the water still in the pipes away from the leak.
3. 3If water is near electrical outlets or the panel, keep clear and call an electrician or the utility.
4. 4If the system will be drained for a while, set a gas water heater to pilot or vacation, or switch off the breaker for an electric one.
5. 5Call a plumber, and tell them whether the main shut-off worked.

If the main valve will not close, call your water utility's emergency line. They can shut the curb stop at the street.

A real example

One of our Google reviews mentions David locating the shut-off valve within minutes of arriving before getting on with the job. Finding the valve is often the first step on a call like that, and everything goes faster, and the water stops sooner, when the homeowner already knows where it is.

When to replace the main valve

Replace the main shut-off if it will not turn, will not seal, or weeps at the handle. In most homes it is a short job: the utility or the plumber shuts the curb stop, the old valve comes out, and a full-port ball valve goes in. It is one of the cheapest pieces of insurance in the house.

While the water is off, it is also a good time to check the pressure. Street pressure in parts of North Jersey can run high, and if it is over 80 psi a pressure reducing valve will protect every fixture and appliance in the house.

The other shut-off valves in your house

The main valve stops everything. For a problem at one fixture, a smaller valve closer to it is quicker and keeps the rest of the house running.

• Under each sink and behind each toilet: small valves, called stops, on the supply lines. Turn clockwise to close.
• At the water heater: a valve on the cold-water pipe going into the top of the tank.
• Behind the washing machine: a hot and a cold valve where the hoses connect. Rubber washing machine hoses are a common cause of floods; braided steel ones last much longer.
• For outdoor taps: an indoor valve on the pipe feeding each one, usually in the basement near the wall. Close it and open the outdoor tap to drain it before the first freeze.

Like the main valve, the small stops can seize after years untouched. Turn each one off and on once a year as well.

Label it

Once you have found the valve, hang a tag on it, and show everyone in the house where it is. If you have tenants or a cleaner, show them too. In an emergency, nobody remembers a valve they were told about once.

The EPA's WaterSense program also has simple guidance on finding and fixing leaks around the home, which is worth a read alongside this.