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Water heater leaking? Do these four things first

Most leaks get worse, not better. Shut the heater down and stop the water first. Then figure out where it is coming from.

1. Turn off the heat

Gas water heater: turn the control knob on the front of the gas valve to OFF (or to PILOT on older units). Most Las Vegas homes with gas use Southwest Gas; if you smell gas, leave the house and call Southwest Gas from outside.
Electric water heater: switch off its breaker in the electrical panel. Never touch the heater's wiring while standing in water.

2. Shut off the cold water going in

Find the valve on the cold pipe at the top of the tank and turn it clockwise until it stops. That stops new water from filling the tank. Many Las Vegas heaters sit in the garage, so the valve is usually easy to reach.

3. Find where the water is coming from

From the pipe fittings on top: often a loose connection or a worn flex line. Usually a repair.
From the relief valve pipe on the side (T&P valve): the valve is letting out pressure. That can mean too much pressure in the house or a failing expansion tank. It needs a plumber, but it does not always mean a new heater.
From the drain valve near the bottom: the valve may not be closed all the way, or it is worn. Usually a repair.
From the bottom of the tank itself: the inside of the tank has rusted through. A tank that leaks from its body cannot be fixed. It needs to be replaced.

4. Drain it if the tank itself is leaking

Attach a garden hose to the drain valve, run it to the driveway or a floor drain, and open the valve. Open a hot water tap in the house so air can get in. The water can be scalding, so let it cool first if you can wait.

Repair or replace a leaking water heater?

Usually a repair: a drip from a pipe fitting, a flex line, the drain valve or the relief valve. These parts are cheap compared with the tank.
Replace: water seeping from the tank body or pooling under the tank, rust streaks on the shell, or a heater past about 10 years old. A tank that has rusted through cannot be patched.
Check first: a wet floor is not always the heater. Condensation on cold pipes and a leaking supply line nearby can look the same. Dry everything with a towel and watch where the first drop forms.

Replacing a heater needs a permit, so ask the plumber whether it is in the quote. See water heater permits in Las Vegas.

Why Las Vegas tanks tend to fail from the bottom

Valley water is very hard. The minerals settle at the bottom of the tank as sediment, which makes the burner or elements work harder and wears the tank out from the bottom up. See hard water and your water heater.

Common questions

Is a leaking water heater dangerous?

The leak itself is mostly a water damage risk. A gas smell or a relief valve that keeps discharging is a safety issue and needs a plumber right away.

What do I do first if my water heater is leaking?

Turn off the gas control knob or the electric breaker, close the cold water valve on top of the tank, then find where the water is coming from. If the tank body is leaking, drain it with a garden hose.

Can a leaking tank be repaired?

Leaks from fittings, the drain valve or the relief valve can often be repaired. A leak from the tank body means the tank has rusted through and must be replaced.