No Hot Water? What to Check First

By McKinney 24 Hour Plumber · Updated September 2026

Start With What Changed

Before touching anything, work out what the symptom actually is, because "no hot water" covers several different faults. Is there no hot water anywhere in the house, or only at one tap? Did it disappear all at once, or has it been running out sooner for weeks? Is the water lukewarm rather than cold? One cold fixture usually points at that fixture's valve or cartridge rather than the heater. A whole house going cold at once points at the unit. Water that runs hot briefly and then goes cold usually means the heater is producing some hot water but not enough, which is a different diagnosis again.

Electric Tank: Check the Breaker

On an electric water heater the most common cause is the simplest one. Look at the breaker panel and find the double-pole breaker for the water heater. If it has tripped, you can reset it once. If it trips again, stop there. A breaker that keeps tripping is telling you something is wrong with an element or the wiring, and repeatedly resetting it is not troubleshooting, it is asking for a bigger problem. Beyond the breaker, the usual culprits are a failed heating element or a thermostat, and both are behind access panels on a live appliance. Testing those is the plumber's job, not a homeowner's, even with the power off.

Gas Tank: Look, Do Not Dismantle

On a gas tank, look through the sight window or observation port to see whether the pilot or burner is lit. If your unit has printed relighting instructions and there is no smell of gas, following those instructions once is reasonable. If it will not stay lit, that usually means a thermocouple, gas control or venting problem and it needs a service visit. If you smell gas at any point, do not try again. Leave the house and call the gas utility first. Do not open the burner compartment, do not remove panels and do not attempt to drain a hot tank to investigate.

Tankless: Read the Error Code

Tankless units are increasingly common in newer homes around McKinney, and they are usually more talkative than a tank. Most display a numeric error code on the front panel or on a remote controller. Write that code down, because it narrows the problem enormously before anyone arrives. Common causes here are scale in the heat exchanger from hard water, a blocked or restricted vent, an ignition fault or insufficient gas supply when several appliances run at once. Some units simply need a reset after a power interruption. What they do not need is anyone opening the cabinet.

Signs It Is Sediment, Not a Sudden Failure

If the hot water has been getting worse gradually rather than stopping overnight, sediment is the usual explanation. North Texas water is hard, and the minerals it carries settle into a hardened layer on the bottom of a tank. That layer insulates the burner from the water, so the heater works longer for less result, and it is what causes the rumbling or popping noise people describe. A tank that has been rumbling for years has usually lost both efficiency and service life. Flushing helps if it is caught early; past a certain point it becomes part of a replacement conversation rather than a repair one.

McKinney Homes and Water Heaters

Where the unit lives matters as much as what it is. Older houses near the McKinney square often have a tank in a closet or utility space, which is easy to work on but means a leak goes straight into the finished floor. Much of the newer slab construction across McKinney and the towns around it puts the heater in the attic, where the first sign of trouble is a stain on a bedroom ceiling rather than anything at the unit itself. Those installations should always have a drain pan with a line running outside; if that line is dripping, the heater is already telling you something. In Melissa and similar fast-built areas, attic installations are close to standard.

When to Stop and Call

Stop if you smell gas, if the breaker trips again after one reset, if there is water pooling around the base of the unit, if the relief valve is discharging, or if the tank is making noises it did not make before. Those are all reasons to leave it alone. A water heater is a pressurized vessel full of very hot water attached to either gas or high-current electricity, and it is not a good place to experiment.

Arrange an Inspection

Give the symptom, the fuel type and any error code when you call, and most of the diagnosis is already done. See what a visit covers on our water heater repair page, weigh the options in our repair versus replacement guide, and if water is appearing somewhere the heater cannot explain, start with leak detection. You can also see how calling works.