Why Is There No Hot Water in My House?

What should you check first when the hot water stops?

Before assuming the water heater has died, rule out the simple things. Many no-hot-water calls come down to a switch, a setting or a shutoff that someone bumped.

Also notice the pattern. Is there no hot water anywhere, or only at one faucet? Does the water run lukewarm instead of cold? Is it hot for a minute and then fades? Each pattern points to a different cause.

• One faucet only: the problem is likely a cartridge, mixing valve or a crossed supply at that fixture, not the heater.
• Every faucet, completely cold: the heater has lost power or fuel, or the cold supply to the tank is the only thing flowing.
• Hot for a short time, then cold: a small tank, a broken dip tube, or a failed lower element can cause this.
• Lukewarm water: the thermostat may be set low, or one of two electric elements may have failed.
• Water that is hot at the tap but discolored or noisy: that is a tank condition problem, covered later in this guide.

1. Confirm the heater is where you think it is and that its cold-water inlet valve is fully open.
2. Look at the thermostat setting and the label on the tank for the manufacturer recommended range.
3. Check whether the house lost power or gas service recently, since a brief outage can leave the heater off.

What causes a gas water heater to stop making hot water?

A gas heater needs three things to work: gas, a flame that stays lit, and a working control. If any of them fails, the water cools down over a few hours.

The most common cause is a pilot flame that went out. A draft, a gas interruption or a worn thermocouple can all blow it out or keep it from staying lit. Newer heaters use electronic ignition and show a status light or code that a technician can read.

• Pilot light out or flickering, often from a draft or a dirty pilot assembly.
• A worn thermocouple or flame sensor that shuts the gas valve off even when the pilot is lit.
• A gas control valve set to off or pilot, or a gas shutoff that has been closed.
• Sediment at the bottom of the tank that insulates the water from the burner and makes the heater work harder.
• A venting problem that triggers a safety shutoff.

Gas safety comes before troubleshooting

If you smell gas, do not try to relight anything. Leave the building, then call the gas utility or 911 from outside. If the heater has a status light, note any code, and follow the manufacturer instructions printed on the tank for relighting. If the instructions are unclear or the pilot will not stay lit after a careful try, stop and call a professional. Do not work on gas valves or fittings yourself.

What causes an electric water heater to run cold?

Electric tanks heat with one or two heating elements controlled by thermostats. When a breaker trips or an element burns out, hot water drops off quickly.

Hard water is common in the Salt Lake Valley, and mineral scale builds up on elements and the tank bottom. Check your water utility published water quality report for the hardness in your area. Scale shortens element life and is a frequent reason the heater runs out of hot water sooner than it used to.

• A tripped breaker or blown fuse on the dedicated circuit.
• A tripped high-limit reset button on the thermostat, which usually means something upstream is wrong.
• A failed upper or lower element, which gives you little or lukewarm hot water.
• A bad thermostat that no longer signals the element to heat.
• A tank that is too small for current household demand.

1. Check the breaker for the water heater and reset it once if it is tripped.
2. If it trips again, leave it off and call for repair; repeated tripping points to a short or failed part.
3. Do not remove the access panels on a heater that is energized; the wiring behind them is live.

When should you call for water heater repair or replacement?

Call when the simple checks do not restore hot water, when a breaker keeps tripping, when the pilot will not stay lit, or when you see water pooling around the base. A leak from the tank body itself generally cannot be repaired, and it means the tank has reached the end of its life.

Age matters too. If the heater is old and failing, repair and replacement are worth comparing. A technician can tell you whether a part is likely to solve the problem or only delay a replacement. Our water heater page explains the repair and replacement options, and the guide on tank versus tankless heaters covers what to consider if you are replacing.

Rocket is based in West Jordan and serves the Salt Lake Valley. You can call or text (385) 722-7638, or schedule online.