Where is my main water shutoff valve, and should I close it when I leave town?

Half the homes in Lee and Collier County sit empty for part of the year. Snowbirds head north in April, families travel in summer, and rentals turn over between guests. An empty house with the water on is a house where a failed supply hose can run for weeks before anyone notices. The single most useful thing a seasonal resident can learn about their plumbing is where the main shutoff valve is and how to prove it works.

Where the main shutoff usually is

Southwest Florida homes are built on slabs, so there is no basement and no crawl space. The water line comes in underground and rises out of the ground at an exterior wall. Look in these places, in this order:

• On the outside wall near a hose bib, most often on the front of the house or the garage side. You will see a pipe coming up out of the ground, a valve, and then the pipe turning into the wall. Some builders put it inside a small plastic box at ground level.
• In the garage, on the wall shared with the house, sometimes near the water heater.
• At the pressure tank, if the home is on a well. The valve between the tank and the house is your shutoff.
• In a utility closet or laundry room in some condos and townhomes. Condo buildings often have a unit valve plus a building valve; your association can tell you which is yours.

The meter box at the street also has a valve. That one belongs to the utility. It needs a special key, it is easy to damage, and most utilities here ask customers not to touch it. Learn the house valve instead.

Two kinds of valves

Ball valve. A lever handle. A quarter turn, so the handle sits across the pipe, is fully closed. This is the modern standard and the one you want.

Gate valve. A round wheel handle that turns several times. Common in homes built before the 2000s. Gate valves seize, the stem breaks, and the gate inside corrodes so the valve “closes” but water keeps flowing. If your home still has one, plan to have it replaced with a ball valve. That is a small job for a plumber and a bad day for a homeowner if the old valve breaks in your hand.

Test it before you need it

Do this twice a year, and always before you leave for the season:

1. Open a faucet inside the house, cold side, and let it run.
2. Close the main valve. A ball valve turns a quarter turn; a gate valve turns clockwise until it stops. Do not force it.
3. Watch the faucet. Flow should drop to nothing within a few seconds. A trickle that never stops means the valve is not sealing.
4. Open the valve again slowly, then run the faucet until the sputtering stops.

If the handle is stuck, stop. Penetrating oil and pliers have snapped more valve stems than they have freed. A stuck main valve is exactly the kind of thing to have fixed on a normal weekday rather than discovered during a leak.

Close it when the house will sit empty

Our rule of thumb: if nobody will be in the house for more than 24 to 48 hours, close the main valve. Weekend trip, fine either way. A week or more, close it. For the season, absolutely.

Before you close it for a long stretch:

• Turn off the breaker to an electric water heater. Leave the tank full. If a hot-side leak drained the tank while you are gone, the elements would burn out dry. Gas and tankless units usually have a vacation mode.
• Close the washing machine valves behind the machine, and look at the hoses while you are there. Rubber hoses are the most common source of a flooded home in this area.
• Leave the irrigation on. It is usually fed ahead of the house valve, so closing the house valve does not affect it. Check that the irrigation backflow device is not dripping.
• Tell whoever checks on the house where the valve is and that it is closed. Many home-watch services will run water briefly on each visit to keep traps from drying out, then close the valve again.

When you come back, open the valve slowly and run each faucet for a minute. Expect some sputtering and a little discoloration from water that sat in the lines.

A step further: automatic shutoff valves

For a home that sits empty every year, an automatic leak-detection valve is worth a conversation. It installs on the main line, watches flow patterns, and closes itself when it sees water running the way a burst hose runs rather than the way a shower runs. Many models send an alert to your phone. It is not a substitute for knowing where your manual valve is, but it is the closest thing to insurance that plumbing offers.

If you are not sure where your valve is, or the one you found does not turn, we can find it, test it, and replace it if needed on the same visit.