Water heater leaking? What to do right now

Step 1: Make it safe

Before touching anything, take a look at what the water is near. If it is pooling around an electrical outlet, a power strip or an extension cord, switch off the circuit at the breaker panel before stepping into the water. If you smell gas, leave the house and call your gas utility from outside, then come back to the leak once they have cleared it.

If the T&P relief valve on the side of the tank is blowing hot water or steam, stay back. That valve opens when the tank is too hot or the pressure too high, and the water coming out can scald. Shut off the heat source (next step) from a safe distance if you can, and let the tank cool.

Step 2: Turn off the heat

Gas tank: turn the knob on the gas control valve to OFF. On newer heaters with an electronic valve, the knob is often on the front of the control unit. You can also close the gas shutoff on the supply line, a yellow-handled ball valve on most installs, by turning the handle across the pipe.

Electric tank: switch off the double breaker labeled for the water heater. This matters more than it seems: if the tank drains while the elements are powered, the elements burn out in seconds.

Tankless: unplug the unit or switch off its circuit, and close the gas valve to it if it is gas-fired.

Step 3: Stop the water

Find the cold water inlet, the pipe coming into the top of the tank with a shutoff valve on it. Close it. A gate valve (round handle) turns clockwise until it stops; a ball valve (lever handle) turns a quarter turn so the lever sits across the pipe.

If that valve will not close, or is leaking itself, close the main water shutoff to the house. It is usually where the water line enters the home, near the meter, in a basement, garage or a box by the curb.

Then open a hot faucet somewhere in the house. That relieves the pressure inside the tank so a leak from the tank body slows to a trickle.

Step 4: Protect the floor and your belongings

Move anything that can absorb water: boxes, rugs, laundry, stored items. Lay towels to steer water toward a floor drain if there is one. A wet-vac makes quick work of standing water on concrete.

If the tank is the problem and it is over finished flooring, you may want to drain it. Attach a garden hose to the drain valve at the bottom, run the hose to a floor drain or outside to a point lower than the valve, and open the valve. Remember that the water will be hot for hours after shutting the heat off.

Take photos and a short video before you clean up: the heater, its rating plate, the puddle and any damaged materials. Insurance claims for sudden water damage often need them.

Step 5: Find where it is coming from

Dry off the outside of the heater and the floor, then watch with a flashlight. Water runs down, so the first wet spot high up is the one that matters.

For more detail on each of these, see leaking water heater repair.

Step 6: Call, and what to say

With the heater off and the water stopped, the urgency drops. You can usually book a same-day or next-morning visit at normal rates rather than paying for midnight service. Call right away only if water is still spreading despite the shutoffs, or if anything is unsafe.

When you call, have this ready:

• Fuel type (gas, electric, tankless) and size from the label.
• Brand and serial number, so the plumber can tell the age.
• Where the leak starts, from step 5.
• Where the heater is installed and how easy it is to reach.
• Whether you want a repair if it is possible, or a replacement price as well.

If it turns out the tank is leaking, ask for a replacement quote that includes the permit, removal of the old tank and any code items such as an expansion tank or drain pan.

What not to do

• Do not plug or cap a dripping relief valve or its discharge pipe.
• Do not turn an electric heater back on until the tank is full and the leak is fixed.
• Do not try to patch a leaking tank with epoxy or tape; it will fail, usually at a worse time.
• Do not ignore a slow drip because it is small. Small leaks rot subfloors and grow mold.

Insurance and water damage

Most homeowners policies cover sudden and accidental water damage, such as a tank that splits and floods a basement. They usually do not cover the water heater itself, wear and tear, or damage from a slow leak that went on for weeks. The difference often comes down to what the adjuster sees and what you can document.

Photograph everything before cleanup, keep the old heater or at least photos of its rating plate and the failure point, and save receipts for any emergency work such as water extraction. If water reached drywall, flooring or cabinets, call a water damage restoration company quickly; drying within the first day or two prevents most mold growth.

Preventing a repeat

Once the heater is fixed or replaced, a few small additions keep the next leak small. A drain pan piped to a floor drain catches drips. A water leak sensor on the floor beside the heater sends an alert to your phone. An automatic shutoff valve on the cold inlet closes the supply the moment it detects water. Together these cost a few hundred dollars and are standard on many new installs in finished spaces.

Living without hot water for a day

If the heater has to stay off overnight, the cold water still works everywhere in the house as long as the main is on and you only closed the heater's cold inlet. Boil a kettle for dishes, and plan on a quick shower somewhere else or a short cold one. Most plumbers can replace a standard tank within a day of the first call, often the same day when the size is in stock.

Questions people ask