Hard water and the bottom of the tank

The City of Caldwell supplies homes from 15 deep wells. The water meets drinking standards, but its calcium and magnesium settle as a layer of sediment in the bottom of a tank. On a gas heater that layer insulates the water from the burner, so the unit runs longer and you hear rumbling or popping as trapped water boils under the scale. On an electric unit, scale coats the lower element until it overheats and fails.

Gas units: pilot, thermocouple, valve

When a gas heater stops making hot water, the usual suspects are a pilot that will not stay lit, a failing thermocouple or flame sensor, or a worn gas control valve. If the pilot goes out again after one careful relight, a part has failed and guessing at it is not worth the risk.

Electric units: elements and thermostats

On electric heaters it is most often a burned-out heating element or a faulty thermostat. Hot water that runs out much faster than it used to is a classic sign that the lower element has quit.

Fixable leaks and the one that is not

A leak from a fitting, the drain valve or the temperature and pressure relief valve can usually be repaired. A leak from the tank body cannot: the steel has corroded through. The anode rod is what protects the tank, and in mineral-heavy water it can be used up in a few years, so it is worth checking during service. Flushing the tank once a year is one of the simplest ways to slow the wear.

Repair or replace

Many tank heaters last roughly 8 to 12 years, often toward the shorter end on Treasure Valley water. Past that range, a major repair is worth weighing against a new tank or a switch to tankless, which also needs descaling on hard water.

If it is leaking now

Turn off the cold water supply to the heater and switch off the power or gas, then call. If you smell gas, leave the house and call the gas utility first. One call to (208) 802-8323 connects you with a local plumber; more on water heater repair in Caldwell and plumbing in Caldwell.