Do You Know Where Your Water Main Valve Is?
Brian Gerken, Master Plumber
February 20, 2025
The Short Answer
In most Long Island homes the water main shutoff is in the basement, on the wall facing the street, near where the water line enters the foundation. Find it before you need it, and confirm it actually turns.
I ask this question a lot, and most people don't know the answer.
When a pipe bursts, you don't have time to find out. Water is coming into your house at full pressure, and every minute between the break and the shutoff is more damage — floors, ceilings, drywall, whatever you had stored down there. The difference between a homeowner who knows where the valve is and one who doesn't is usually the difference between a repair and a renovation.
Go find it now, while nothing is wrong.
In most Long Island homes it's in the basement, on the wall facing the street, near where the water line comes in through the foundation. It's usually a wheel handle or a lever. If you're in a crawl space or a slab home, it may be in a utility closet or near the water heater.
Once you've found it:
- •Turn it. Make sure it actually moves. Valves that haven't been touched in twenty years seize up, and finding that out during an emergency is the worst possible time.
- •Show everyone in the house. Anyone old enough to be home alone should know where it is.
- •Keep the path to it clear. Don't stack boxes in front of it.
If your valve won't turn, or you can't find it at all, call me. That's a small job on a normal Tuesday and a disaster at two in the morning.
Common Questions
What if my water main valve won't turn?
Valves that haven't been touched in years seize up. Don't force it with a wrench — you can snap the stem and cause the leak you were trying to prevent. Call a plumber. Replacing a seized shutoff valve is a small, routine job on a normal day, and it's a lot cheaper than an emergency visit at 2 AM.
Is there a shutoff outside the house too?
Yes, most homes have a curb stop valve at the property line near the street, but it requires a special key to turn and it's usually buried under a small access cap. That's the water company's valve. The one inside your basement is the one you should know and use.
Should I shut the water off when I go on vacation?
Absolutely. If a pipe bursts while you're away, nobody's home to hear it or shut it off. Turn the main valve off before you leave and drain the system by opening a faucet on the lowest floor. It takes two minutes and it can save you coming home to a flooded house.
Have a question about your own house?
I talk to every customer myself. Call the shop and ask.