A water heater usually leaks or bursts for one of three reasons: the tank has rusted through after its anode rod wore out, sediment has built up in the bottom of the tank, or pressure inside the tank has climbed too high. Yearly maintenance catches all three before they flood your home.
If water is coming from your water heater right now, start with the steps below. If the tank has burst, call an emergency plumber.
What to Do if Your Water Heater Is Leaking
- Turn off the heat. Switch off the breaker for an electric water heater, or turn the gas control to Off on a gas water heater.
- Shut off the water. Close the cold water valve above the water heater.
- Catch the water. Put a bucket under the leak.
- Drain the tank if needed. Connect a garden hose to the drain valve and run it to a floor drain. Open the hot water faucet farthest from the water heater, then open the drain valve. The water may be hot.
These steps follow Rheem’s guidance for a leaking water heater. If you would rather not do them yourself, call a plumber.
Signs Your Water Heater Is Failing
- Rusty or brown water from the hot tap
- Popping, crackling or rumbling sounds from the tank
- Water pooling around the base
- A temperature and pressure relief valve that drips or discharges
Leaky valves can often be tightened or replaced. If the tank itself is corroded through and leaking, it’s time for a replacement. See 3 signs it’s time to replace your water heater and our water heater troubleshooting guide.
Why Water Heaters Leak or Burst
A Rusted Tank
A steel tank is protected by a “sacrificial” anode rod, which corrodes so the tank doesn’t. Once the rod is used up, the tank itself starts to rust. Brown or rust-colored hot water is a warning sign.
How to prevent it: Rheem’s use and care manual calls for removing the anode rod once a year for inspection and replacing it when more than 6 inches of its core wire is exposed. A plumber can check it during routine maintenance.
Sediment Buildup
Minerals in hard water settle to the bottom of the tank as sediment. That layer insulates the water from the burner or heating element, so the heater runs longer and the tank overheats and wears out faster. Popping or crackling noises mean water trapped under the sediment is boiling and escaping.
How to prevent it: Drain sediment from the tank regularly. Rheem suggests draining a few quarts from the tank every month.
Too Much Pressure
Water expands as it heats. In a closed system, where a check valve or pressure-reducing valve keeps water from flowing back into the main, the extra volume has nowhere to go, so pressure in the tank climbs. The temperature and pressure (T&P) relief valve opens to release it. A relief valve that drips or discharges often is a sign of this thermal expansion, and repeated high pressure can weaken the tank over time.
How to prevent it:
- At least once a year, lift and release the T&P valve’s lever to make sure it operates freely, as Rheem recommends. The water that comes out will be hot.
- If the valve discharges often, have a plumber check for thermal expansion. Rheem recommends an expansion tank on the cold water line in a closed system.
- Never plug or cap the relief valve or its discharge pipe.
- Set the water heater to 120°F. The U.S. Consumer Product Safety Commission recommends 120°F, and Rheem warns that water above 125°F can cause severe burns. See what temperature to set your water heater.
Water Heater Leak FAQ
Why is my water heater leaking from the bottom?
Water at the base can come from the drain valve, the relief valve’s discharge pipe or the tank itself. A leaking valve can often be tightened or replaced. A tank that is corroded through needs to be replaced.
Can a water heater explode?
The T&P relief valve is there to release pressure before the tank fails. That is why the valve should be tested every year and never plugged or capped.
Why is the relief valve on my water heater dripping?
Most often it is thermal expansion in a closed water system. Rheem recommends an expansion tank on the cold water line. Don’t plug the valve. Have a plumber find the cause.
How often should a water heater be serviced?
Once a year: test the T&P valve, inspect the anode rod and flush the sediment. Rheem also suggests draining a few quarts every month.
Schedule Water Heater Maintenance
These tasks aren’t hard, but they are easy to forget. Central Heating Cooling Plumbing Electrical can inspect your water heater, test the relief valve, check the anode rod and flush the tank. We serve Kalispell, Whitefish, Bigfork, Columbia Falls and the rest of the Flathead Valley. Call 406-756-6656 or see our water heater services. If your water heater has burst, contact our emergency plumbers. Your Comfort Is Our Central Concern.
A tankless water heater has no storage tank to rupture. Learn more about the benefits of tankless water heaters.
