Should I turn off my water heater when I leave for the season?

Half of Lee and Collier County packs up in April and comes back in November. The water heater sits in a hot garage for those months, heating water nobody uses, with the pressure of the whole house behind it. Shutting it down properly takes five minutes and removes one of the two most common ways a seasonal home floods while empty. The other is a washing machine hose, which has its own guide.

Everything below assumes you also close the main water valve to the house when you leave, which is the single most important thing a seasonal resident can do. The water heater steps come after that.

Gas heaters: use the Vacation setting

The gas control on the front of a tank heater has a dial or a button with a Vacation or VAC setting. It keeps the pilot lit and holds the tank at a low temperature so the burner rarely runs. On newer electronic controls it is a menu option. Set it, and that is all. Do not turn the control fully off unless you are comfortable relighting the pilot in the fall, and know that a pilot in a garage can still go out from a storm-driven draft while you are gone.

If the house is on propane, note the tank level before leaving. A heater on Vacation uses very little, but a nearly empty propane tank with a pilot burning for six months can run out.

Electric heaters: breaker off and the main closed

An electric tank has no vacation setting worth the name. Go to the panel and turn off the double-pole breaker labeled for the water heater. With the main closed too, the tank sits full, sealed, and cold. Nothing is heating, nothing is pressurizing, and if a fitting fails, there is only what is already in the tank to leak.

Tape a note to the breaker panel and another to the heater so a caretaker or a family member does not flip the breaker back on with the water off. That is the most common way an element burns out in a closed-up house.

Two things not to do: drain it, or leave it lukewarm

It feels sensible to empty the tank before leaving. Do not. An empty steel tank in a humid garage rusts from the inside faster than a full one, the sediment dries into a crust, the drain valve is often a plastic spigot that will not reseal after its first opening in years, and a tank that is drained and then powered by mistake is destroyed in seconds. Leave it full and cold.

The same logic applies in hurricane season: a full water heater tank is 40 or 50 gallons of clean water you can draw from the drain valve if a storm takes out the utility. That is a reason to keep it full, not a reason to drain it.

The other mistake is leaving an electric heater on with the thermostat turned down low. Water held for months between roughly 80 and 115 degrees is the range where Legionella bacteria multiply, and the first shower in November delivers a warm mist of it. A heater in use sits at about 120 degrees. A heater not in use is off. Not lukewarm.

Tankless units

A tankless heater only runs when water flows, so with the main closed it does nothing. Turn it off at its switch or breaker anyway, and if it has a recirculation pump on a timer, shut the timer off so it is not trying to move water through a closed system. If the unit has isolation valves, this is a good time for the annual descaling flush, so it sits clean through the summer.

Restarting safely when you come back

The order matters, and it is the reverse of shutdown.

1. Open the main water valve slowly. Walk the house listening for running water you did not turn on.
2. Open a hot tap, the tub is best, and let it run. It will spit and sputter as the air in the lines and at the top of the tank purges. Keep it running until the flow is steady with no air.
3. Check that the cold inlet valve on top of the heater is fully open.
4. Only now restore power: turn the breaker on, or turn the gas control from Vacation back to your normal setting.
5. Give the tank an hour or so, then check for hot water, and walk back to the heater and look for drips at the fittings and at the relief valve.

The first hot water after months away may carry a rotten egg smell. That is bacteria that grew in the still tank reacting with the anode rod, and it usually clears after running the hot water hard for a day. If it does not, there is a separate guide on that.

Check the pan and relief valve before you unpack

Before the heater goes back on, look at three things:

• The drain pan. Dry is the answer you want. Standing water, a rusty tide line, or a dried mineral ring means the tank or a fitting wept while you were gone. Find out which before you heat it.
• The relief valve. Look at the end of the discharge pipe. Dried mineral or a wet spot means it opened at some point. A relief valve that discharges in an empty house with the main closed is unusual and worth a look.
• The base of the tank. Rust streaks down the jacket or corrosion at the bottom seam on a tank past its eighth year are the tank telling you it would like to be replaced before next season.

If you would rather have the heater and the rest of the house shut down and restarted by a plumber, or you have come back to something in the pan, send us a photo and tell us how old the tank is. It is easier to plan a replacement in November than to have one forced on you in July.