When the hot water stops, the cause is usually one of a few things: a gas heater whose pilot or burner has gone out, an electric heater with a tripped breaker or safety cutoff, or a tankless unit that has locked out on an error code. A few safe checks, done in the right order, tell you whether it is a quick fix, a repair, or a heater at the end of its life.
Start with one question. If you smell gas, stop here. Do not touch any switches or try to relight anything. Leave the house and call SoCalGas or 911 from outside.
First, narrow it down
- No hot water anywhere points to the heater itself or its gas or power supply.
- One tap or shower is cold, the rest are fine points to that fixture, often a worn mixing valve, not the heater.
- Hot water runs out fast is a different problem. On a tank it is usually sediment, a failed heating element, or a heater too small for the household.
- Lukewarm only often means a thermostat set too low, a failed element on an electric tank, or scale in a tankless unit.
Gas tank water heaters
In many Valencia, Saugus and Canyon Country homes the water heater is a gas tank in the garage. Look at the lower front of the tank.
- Check the control knob. It should be set to On, not Pilot or Off. Someone bumping it while moving boxes is more common than you would think.
- Look for the pilot. Older tanks have a small window. A steady blue flame means the pilot is fine. No flame means it has gone out.
- Relight only by the label. The lighting instructions are printed on the tank. Follow them exactly. If the pilot will not stay lit after you release the button, the thermocouple or flame sensor has likely failed. That is a repair, not something to keep retrying.
- Newer sealed units often have a status light instead of a window. The blink pattern is explained on the label or in the manual.
Electric tank water heaters
- Check the breaker. A water heater runs on its own double breaker. If it has tripped, reset it once.
- If it trips again, leave it off. A breaker that trips twice is reporting a fault, often a shorted element or a wiring problem, and resetting it again is not safe.
- The high-limit reset. Electric tanks have a red reset button behind the upper access panel. It trips when the water overheats. With the power off at the breaker, pressing it can bring the heater back. If it trips again, the thermostat needs replacing.
Tankless water heaters
Tankless units report most faults as a code on the front display. Write it down before you reset anything, because it tells a plumber most of what they need to know. Check that the gas valve to the unit is open and, on gas models, that other gas appliances still work. A unit that keeps locking out, or swings between hot and cold, is often scaled up inside. Valley water is very hard, so our guide to flushing a tankless water heater is worth reading if yours has not been descaled in the last year.
Check the temperature setting
If the water is warm but never hot, look at the setting. The U.S. Department of Energy recommends setting a water heater to 120°F, "a temperature considered safe for most of the population" (DOE Energy Saver Guide, 2022). Turn it up gradually rather than all the way. Water much hotter than that scalds quickly, which matters in a house with young children or older relatives.
Signs it is a replacement, not a repair
A repair makes sense for a failed thermocouple, element, thermostat or gas valve on a heater with years left in it. These point the other way:
- Water leaking from the tank itself, not from a fitting or the relief valve pipe.
- Rusty water from hot taps only.
- A tank around ten years old or more. Santa Clarita's hard water shortens tank life, so heaters here often age faster than the label suggests.
If any of those apply, our guide to the signs you need a new water heater covers sizing and what moves the price.
If the tank is leaking, turn off the cold water valve above the heater and turn off the gas or the breaker. That stops the leak getting worse while you arrange the work.
When to call us
Call a licensed plumber when the pilot will not stay lit, a breaker or reset button keeps tripping, there is a gas smell or scorching around the burner, or the tank is leaking. Gas valves, burners and electrical parts are not DIY repairs.
BluePoint Plumbing repairs and replaces gas, electric and tankless water heaters across the Santa Clarita Valley, and we answer the phone around the clock for emergencies. See our water heater repair and replacement service in Santa Clarita, or get in touch and tell us what you have checked so far.