No Hot Water? What to Check

By the Plano 24 Hour Plumber team · Updated September 2026

Is It One Fixture or the Whole House?

Start here, because it splits the problem in half. Run the hot tap at two or three fixtures in different rooms. If only one of them is cold, the heater is fine and the problem is at that fixture: a mixing valve, a cartridge, a blocked aerator or a stop valve that has been knocked closed. If every hot tap in the house runs cold, the heater or its supply is the place to look.

Do the same with quantity. Hot water that runs out after a few minutes when it used to last much longer is a different symptom from no hot water at all, and it usually points at sediment in the tank or a failed lower heating element rather than a dead unit.

Electric Water Heaters

On an electric unit the most common cause is the simplest: the breaker. Go to the panel and look for a tripped breaker for the water heater. Resetting it once is reasonable. If it trips again straight away, stop and call, because a breaker that keeps tripping is telling you about a fault rather than being awkward.

Many electric heaters also have a reset button on the thermostat behind an access panel. Some manufacturers expect an owner to press it; others really do not. If pressing it requires removing a cover to expose wiring, that is the point to hand over. Beyond the breaker, the usual culprits are a heating element, a thermostat or the high-limit switch, and all three need testing rather than guessing.

Gas Water Heaters

On a gas unit, the pilot or igniter, the thermocouple and the gas valve are the common failure points. You can look at the unit, note any error lights and check that the gas supply to the house is on and that other gas appliances are working. That is the extent of what is worth doing yourself.

Do not dismantle a burner assembly, do not attempt repairs on a gas connection and do not keep trying to light a pilot that will not stay lit. A pilot that goes out repeatedly is usually a failing thermocouple, which is a straightforward repair for a plumber and an unnecessary risk for anyone else. If you smell gas, leave the building and call the gas utility first.

Tankless Systems

Tankless units generally tell you what is wrong if you read them. There is normally a display with an error code, and the code has a specific meaning in the manual. Note it down before you call; it saves time and often identifies the part needed.

The other common tankless complaint is water that alternates between hot and cold, or takes a long time to arrive. In hard water, a scaled heat exchanger is frequently behind it. Flushing a tankless heater is routine maintenance in this area rather than a repair, and a unit that has never been flushed will underperform long before it fails.

Hard Water Is the Background Factor

North Texas water is hard, and that shapes what goes wrong with heaters here. In a tank, minerals settle to the bottom and form a layer that insulates the water from the burner or element, so the unit works harder, takes longer and delivers less. The rumbling or popping some tanks make while heating is that sediment. In a tankless unit, the same minerals coat the heat exchanger.

It also explains why age matters more locally than the number printed on a warranty. A tank that has spent its whole life in hard water without being flushed is nearer the end than one in a softer-water region. That is worth knowing before you spend on a repair; the repair versus replacement comparison sets out how that decision usually goes.

Attic Installs Around Plano

A large share of houses in Plano and the towns around it have the water heater in the attic or a closet above living space. It keeps the floor area free, but it means a leak arrives through your ceiling rather than across a garage floor. If you are checking a heater because hot water has stopped, take thirty seconds to look at the drip pan and the ceiling below it while you are there.

A stain on a ceiling under an attic heater changes the urgency completely. That is not a hot water inconvenience; it is water escaping into the structure. Houses of similar age tend to hit this at similar times, which is why streets in Allen and other 1990s and 2000s subdivisions see clusters of heater replacements in the same few years.

Arrange an Inspection

If the breaker is fine, the pilot will not stay lit, the error code keeps returning or the hot water has simply gone, call Plano 24 Hour Plumber and describe the unit, its location and what it is doing. See water heater repair for what the visit covers, leak detection if there is a stain you cannot explain, and how a service call works for the order things happen in. You can also send the details here.