First: is it every faucet?
If only one faucet or shower runs cold, the problem is probably that fixture’s valve or cartridge, not the water heater. If every faucet in the house is cold, start with the water heater.
Gas water heater: check the gas and the pilot
- Check the gas valveThe valve on the gas line to the heater should be open, with the handle running in line with the pipe.
- Look for the pilotLook through the small window near the bottom of the tank for a small blue flame. Many newer heaters have a status light that blinks a code instead.
- Relight it the right wayIf the pilot is out, follow the relighting steps printed on the label on the tank, exactly as written.
If the pilot lights but won’t stay lit, the part that senses the flame may be worn out. That’s usually a quick repair for a plumber.
Tip: If you smell gas, don’t try to relight anything. Leave the house and call SoCalGas at 1-800-427-2200 or 911 from outside.
Electric water heater: check the breaker
Find the water heater’s breaker in your electrical panel. If it has tripped, reset it once. If it trips again, leave it off and call a plumber, because a heating element or thermostat has probably failed.
Tankless water heater: check the error code
Most tankless heaters show an error code on the front panel when they stop working. Write it down, because it tells a plumber a lot before they arrive. Also make sure the unit has power and gas, and that the water inlet filter isn’t clogged.
Much of LA has hard water, and scale buildup is one of the most common reasons tankless heaters shut down. A yearly flush keeps them running.
Hot water that runs out fast
If you get some hot water but it runs out quickly, sediment may have built up in the bottom of the tank, a part inside the tank may have broken, or the heater may be too small for your household. Flushing the tank once a year helps prevent sediment problems.
When to call a plumber
- Water is pooling around the base of the tank.
- The hot water looks rusty or smells like rotten eggs.
- The tank makes popping or rumbling sounds.
- The pilot won’t stay lit, or the breaker keeps tripping.
- The heater is more than 8 to 12 years old, which is the usual lifespan of a tank heater.