WATER HEATERS
No Hot Water? Work Through This Before You Call
Some no hot water calls are resolved by the homeowner in four minutes. Others should not be touched at all. Knowing which is which is the whole point of this page.
There is a sensible order for diagnosing a heater that has stopped producing hot water, and following it resolves a fair number of cases without anyone visiting. There is also a clear line past which the correct action is to stop, and this page marks both.
Start by establishing which type of unit you have, because the diagnosis diverges immediately. A gas unit has a flue and a gas supply line running to it. An electric unit has a heavy cable and no flue.
If it is electric: the two checks worth making
First, the breaker. Electric water heaters run on a dedicated double pole breaker in the panel, and a tripped breaker is the single most common cause of a complete loss of hot water. Confirm it is in the on position. If it has tripped, reset it once. If it trips again immediately, stop, because a breaker tripping repeatedly is reporting a fault rather than misbehaving.
Second, the high temperature cutout. Electric heaters have a reset button, usually behind an access panel on the upper thermostat. Pressing it once is reasonable. If it trips again, that is a thermostat or element fault and it needs diagnosis rather than another reset.
Beyond those two, the work involves testing elements and thermostats on a unit carrying substantial voltage, and that is where the homeowner portion of this ends.
If it is gas: check the pilot or the display
On an older standing pilot unit, look through the sight glass at the base. No flame means the pilot is out, and relighting it following the instructions printed on the unit is a reasonable thing to attempt once. If it will not stay lit, or it goes out again within a day, the thermocouple is the usual culprit and that is a service item.
On a newer unit with electronic ignition, there is generally a status light or a display, and it will be reporting a code. Note the code before calling, since it tells whoever attends a great deal about what has failed and can save a diagnostic visit.
If at any point you smell gas, none of this applies. Leave the building without operating any switches, and call the gas utility from outside.
| Symptom | Gas unit | Electric unit |
|---|---|---|
| No hot water at all | Pilot out, thermocouple, gas valve | Breaker, upper element, thermostat |
| Lukewarm water only | Thermostat setting, partial burner fault | Lower element failed, upper still working |
| Runs out much faster than it used to | Sediment reducing effective capacity | Sediment, or lower element failed |
| Popping or rumbling | Sediment in the base | Sediment on the elements |
| Rusty water at hot taps only | Anode consumed, tank corroding | Anode consumed, tank corroding |
| Water pooling at the base | Tank failure, usually terminal | Tank failure, usually terminal |
| Relief valve discharging | Pressure or temperature fault, needs diagnosis | Same, and it is a safety device doing its job |
The one symptom that ends the diagnosis
Water pooling around the base of the tank, once you have ruled out a dripping relief valve or a loose fitting, means the tank itself has failed. Steel tanks corrode from the inside, and once the shell is compromised there is no repair. That unit is finished.
The right response is to close the cold water inlet valve at the top of the tank, shut off the gas or the breaker, and arrange replacement. A tank that is weeping today can open up considerably tonight, and on a garage installation against a shared wall that becomes a water damage event rather than an appliance one.
Tank leaking from the base?
Close the cold inlet and the gas now, then call.
Why sediment explains most of the middle rows
Several of the symptoms in that table share one cause, and it is the local one. A supply running 6 to 17 grains per gallon deposits mineral in the base of a storage tank continuously.
That deposit occupies volume, which is why a tank runs out faster than it used to. It insulates the burner from the water, which is why recovery slows and gas usage rises. It traps heat against the steel, which accelerates the corrosion that eventually ends the tank. And it makes the popping noise that people describe as the heater complaining.
An annual flush removes it, and it is a short job. Where a unit has never been flushed in eight years, the flush may release enough material to reveal problems rather than solve them, which is an argument for starting the habit early rather than an argument against starting it at all.
Repair or replace, at a glance
Repair is usually right for a thermocouple, a single element, a thermostat, a relief valve or a gas control on a unit that is not old. Those are components and they are replaceable.
Replacement is usually right when the tank leaks, when the unit is past the typical service window and needs a significant part, or when repair cost is approaching a meaningful fraction of a new installation. The awkward middle case is a seven or eight year old unit needing a moderate repair, and there the honest question is whether you want to spend that money on a unit that will need replacing within a couple of years anyway.
Whatever the answer, if the supply is untreated, fitting a softener alongside the new unit is what determines whether you have this same conversation again in seven years.
What to have ready when you call
Four pieces of information turn a diagnostic visit into a repair visit, and they take two minutes to collect.
The type and fuel, meaning gas or electric, tank or tankless. The age, which is usually encoded in the serial number on the data plate and is often readable directly. The capacity, also on the plate. And any error code the unit is displaying, written down exactly rather than approximately.
With those four, whoever attends can arrive with the likely parts rather than diagnosing first and returning later. It is the difference between one visit and two, and on a household with no hot water that difference is the one you actually care about. If the unit turns out to be beyond repair, the same details make the replacement conversation immediate rather than another appointment.
Finally, a word on the relief valve, because it is the component people most often misread. A temperature and pressure relief valve discharging is not a faulty valve doing something annoying; it is a safety device reporting that the system has exceeded a safe temperature or pressure. Capping it, plugging it or replacing it without establishing why it opened removes the protection rather than the problem, and it is one of the few genuinely dangerous shortcuts available on a domestic water heater.
Codes, standards and licensing this work sits under
Residential plumbing in Queen Creek is carried out under the codes the Town has adopted, currently the 2021 International Codes, effective 1 January 2023, alongside the 2020 National Electrical Code (NEC) where electrical work is involved. The two model plumbing codes those adoptions draw from, the Uniform Plumbing Code (UPC) and the International Plumbing Code (IPC), are the documents that set out how supply, waste and venting are expected to be built. Permitted work is plan reviewed and inspected by Queen Creek Building Safety; on the Pinal County side confirm the current issuing authority for your address. Contractor licensing in this state runs through the Arizona Registrar of Contractors, utility locates are requested through Arizona 811 before any excavation, and drying after a water escape follows the published ANSI/IICRC S500 standard. Naming these standards describes the rules the work is done to. It is not a claim to hold any particular certification, and if a certification or licence number matters to you, ask for it on the phone and check it yourself.
Four minutes of checking, then stop
If it is past the breaker and the pilot, call rather than continue.