Why do I have no hot water?

The usual reasons for no hot water are a tripped breaker or dead thermostat on an electric heater, a pilot that went out on a gas heater, a dead heating element or gas valve, a tank packed with sediment, a broken dip tube, a shut valve, or a faulty mixing valve at the tap. Begin with the power and fuel, then move on to the parts. Our water heater page covers repair and replacement once you know the cause.

What should I check first when there is no hot water?

Check whether the heater has power or fuel. On an electric unit, look at the breaker and the red reset button under the thermostat cover. On a gas unit, look through the small window to see the pilot. Then check whether other taps give hot water, since a fault at a single tap points to the fixture, not the heater.

Run the hot tap nearest the heater for a minute. If it is cold there too, the problem is at the heater. If it is hot there and cold elsewhere, the problem is in the pipes or at the fixture.

Next, check that the heater's cold water supply valve is open and that the thermostat is set to about 120 degrees Fahrenheit, a common recommended setting. A tank turned down to vacation mode looks exactly like a dead one.

Smell gas at any point and you should exit the building, reach SoCalGas at 1-800-427-2200 once outdoors, and dial 911 if anyone is at risk. Light nothing and flip no switches.

Why is there no hot water from an electric water heater?

Typical culprits include a tripped breaker, a popped high-limit reset, a burnt-out upper or lower element, or a dead thermostat. Electric tanks carry two elements. When just the lower one dies, hot water runs out quickly. When the upper one dies, there is none. Testing either takes a meter and the power off.

Press the red reset button once, after the breaker is off, then turn the power back on. Should the breaker trip once more, stop there. A shorted element or wiring fault is the likely reason. Repeated resetting is a fire risk. The tests are laid out on no hot water from an electric heater and thermostat replacement covers that part.

Hard water speeds element failure, because scale insulates the element and makes it overheat. Valley homes see this often. Replacing an element is within reach of a careful handy owner with the power off. Anything involving the panel or wiring is a job for a person with the proper license.

Why is there no hot water from a gas water heater?

On a gas heater the cause is usually a pilot that has blown out, a worn thermocouple or flame sensor, a failed gas control valve or a blocked vent or burner. If the pilot is out, the unit makes no heat. When a pilot refuses to stay lit, suspect the thermocouple, a small part a plumber can replace quickly.

With the pilot out and no gas odor, the relighting steps on the heater's label are fair to follow. Should it die again within a day, stop and call. Any gas smell means you leave. Our page on pilot light repair shows what a plumber checks.

Gas control valves and venting are regulated work. California law expects a plumber with a contractor license to handle gas piping and permitted replacements. See gas valve replacement on a water heater.

Newer gas heaters have no standing pilot and use electronic ignition, so a power outage or a failed igniter can cause the same symptom. A flashing status light usually has a code in the manual that points to the fault.

Why do I have no hot water but the pilot is lit or the heater is on?

If the heater runs but the water is cold at the tap, the cause is often a broken dip tube, a stuck mixing or anti-scald valve, sediment, a leak in the hot line, or a closed valve. A failed dip tube sends cold water in at the upper part of the tank rather than the bottom, so you get lukewarm water that fades fast.

Old plastic dip tubes can crumble into white flakes that clog aerators and showerheads. If you find them, a plumber can replace the tube. See dip tube replacement.

Single-handle shower valves with a cartridge also fail. A hot kitchen sink with a cold shower suggests the shower cartridge or mixing valve. Read about no hot water from the shower or no hot water at the kitchen sink. A washing machine with cold wash water has its own causes, covered on washing machine no hot water.

Why do I have no hot water from a tankless heater?

Tankless units shut down for a reason: a clogged inlet filter, scale inside the heat exchanger, a low flow that never triggers the burner, a blocked vent, a lost power connection, or an error code. Many tell you the code on a display. Check the manual, since the code often names the fault.

Wikipedia's overview of tankless heating notes that regular descaling is essential and that manufacturers call for yearly maintenance in hard water. A unit that has never been descaled is the usual patient. Flushing it with vinegar or a descaling solution is within a handy person's reach on some models, while gas and vent faults are not.

Cross-connected plumbing is another cause. If a faucet mixes hot and cold in the wrong place, a tankless unit may sense too little flow and shut off. A plumber can trace it.

When is no hot water an emergency, and what does a plumber charge?

In most cases it can wait a day or two, unless there is a leak, a gas smell or an overheating tank. See emergency water heater repair for those cases. As a guide, small repairs run about $150 to $500, and a replacement tank commonly $1,500 to $3,500 installed in the Burbank area.

Renters should know that California treats hot water as part of a habitable home, so tell your landlord in writing. If the whole building has lost hot water, read about apartment building no hot water.

To get help, request a quote and a local plumber comes out to inspect. The price reaches you in writing ahead of any work. The rest of our Burbank and Valley services are listed on the Lankershim Plumbing home page.

Questions people ask

Why is the water cold when the heater is on?

The heater may be heating but not delivering. Suspects are a broken dip tube, a bad mixing valve at the tap, a shut valve, sediment, or one dead element on an electric tank with two. A tripped limit switch can also stop heat while the unit looks on. A plumber can test the elements and thermostat to find it.

Is it the water heater or the faucet?

Test several taps. If every hot tap is cold, the heater or its supply is the problem. If only one fixture is cold, the cause is at that fixture: a cartridge, a mixing valve or a blocked aerator. A hot tap right beside the heater that runs cold points to the heater itself.

How long should I wait for water to heat after I reset the breaker?

A standard 40 to 50 gallon electric tank usually needs one to two hours to heat from cold, and a gas tank often less. If the water is still cold after three hours, an element, thermostat or the limit switch has probably failed. Do not keep resetting a breaker that trips again.

Can low gas pressure or a utility problem cause no hot water?

Yes, though it is rare. A gas outage or a closed valve will stop a gas heater, and a power outage stops electric and many gas models. Check whether the stove works. If the utility has a problem, SoCalGas takes calls at 1-800-427-2200. A gas smell means getting out first and calling from outdoors.

Why are plumbers against tankless water heaters?

Not all are. The usual objections are cost, bigger gas lines and venting, and the need for yearly descaling in hard water. A tankless unit that is sized and maintained well works fine. A good plumber prices both types for your home and explains the trade-offs honestly.