Water heater leaking: what should you do first?

What should you do first if your water heater is leaking?

Check for a gas smell before you do anything else. If you smell gas, follow step 1 and skip the rest of this list.

1. Check for a gas smell. If you smell gas anywhere in the house, don’t use a light switch or your phone, and don’t smoke or light a match. FortisBC’s gas leak advice is to get out, leave the door open behind you, and call the FortisBC emergency line or 911 once you’re outside.
2. Close the cold water supply valve. It’s usually on the cold pipe going into the top of a tank, or underneath a tankless unit. Turn a round handle clockwise until it stops, or turn a lever so it sits across the pipe. If the valve won’t move or keeps dripping, close the house’s main water shutoff.
3. Turn the heater off.
   • Gas tank: follow the shutdown instructions on the tank’s label. On most tanks that means turning the gas control knob to OFF. If you also close the shutoff valve on the gas line, turn the handle until it sits sideways across the pipe. FortisBC’s appliance safety page says that’s the off position. Leave turning the gas back on and relighting to whoever repairs the heater.
   • Electric tank: most have no on/off switch, so switch off the water heater’s breaker, or the disconnect switch on the wall beside the heater if it has one. Don’t touch the panel or a switch if the floor is wet.
   • Tankless: if the unit is dry and you’re on a dry floor, press the power button on its control panel to stop it heating. That button usually doesn’t cut the power, so treat the unit and its wiring as live.
4. Keep clear. Water from a relief valve or a failed tank can scald, so keep children and pets out of the room. Leave draining the tank to a plumber.
5. Take photos of the leak. If you can do it without stepping in hot water or in water near an outlet or the heater’s wiring, move boxes off the wet floor.

Why is your water heater leaking?

A water heater usually leaks from the relief valve, the pipe connections on top, the drain valve near the bottom, or the tank itself. Check where the water is before you mop it up.

• If water is running out of the pipe down the side of the tank, it’s coming from the temperature and pressure (T&P) relief valve, which lets water out when the temperature or pressure gets too high. Never cap, plug or remove that pipe.
• Drips on top of the tank usually come from the pipe connections or the flexible connectors.
• A puddle at the front near the bottom can be the drain valve weeping past a worn seal.
• Water seeping out from under the outer jacket, or pooling under the tank with nothing dripping from above, often means the inner tank has rusted through. A leaking element gasket on an electric tank or condensation on a gas tank can look similar, so get a plumber to check before you replace the heater.
• The water may not be from the heater at all. Check for a leaking furnace condensate line or washing machine hose nearby, or a backed-up floor drain.

Should you repair or replace a leaking water heater?

Repair it if the leak comes from a valve or a fitting. Replace it if the tank itself is leaking, because a steel tank that has rusted through can’t be patched.

If the leak is repairable, check the tank’s age. The manufacture date is on the rating plate or coded into the serial number. If the tank is old and there’s rust around the base, replacing it often makes more sense than fixing a valve.

If the relief valve keeps opening, a new valve may not stop it. High water pressure or a faulty thermostat can make a good valve open, so ask the plumber to find the cause.

Search the Technical Safety BC recalls page for the brand and model on your heater’s label. It lists some tankless and gas water heater recalls but notes that not every recall is posted, so ask the manufacturer too.

Do you need a permit to replace a water heater in BC?

Installing a new gas water heater will likely need a permit. Technical Safety BC’s page on home modifications says most gas and electrical work in BC is regulated under the Safety Standards Act, and that a licensed contractor you hire gets the permit for you.

Have the new tank strapped so the water and gas lines are less likely to break in an earthquake. The BC Building and Plumbing Codes now require it, according to FortisBC’s appliance safety page.

What should you do if your tankless water heater is leaking?

Close the shutoff valve on the cold pipe under the unit, and the one on the hot pipe if there is one. Then, if the unit and the floor are dry, turn it off at its control panel. With no tank to empty, the leak should slow to a drip. The likely leak points are the connections, a pressure relief valve if one is fitted, and the heat exchanger inside the cabinet.

On a gas tankless unit, FortisBC’s appliance safety page tells you to call a licensed gas contractor if water leaks from the unit or its piping, soot or dust shows up around the exhaust vent, or the unit makes abnormal sounds when it runs. If there’s soot, leave the unit off until a gas contractor has checked it.

If water is reaching the unit’s plug or wiring, stay back and don’t unplug it. Switch off its breaker only if you can reach the panel from a dry floor. Otherwise, keep everyone out of the room until the power can be shut off safely.

When to call a plumber

Call a plumber once the water is off and the heater is shut down. Treat it as an emergency if you can’t stop the water or it’s spreading toward outlets or the electrical panel. If you smell gas, get outside and call FortisBC or 911 first.

DrainX repairs and installs tank and tankless water heaters, apart from the gas connection. It fixes leaking pipes and fittings too, including on emergency calls.