How Long Water Heaters Last in Arizona

Go read the sticker

Pause and go out to the garage. Find the label on the side of the tank and look at the serial number. On most brands the manufacture date is coded into it, and the first four digits usually give you the year and the month or week. Rheem's own guidance says the same thing: the manufacture date is in the serial number, and knowing the age is where every repair or replace decision starts.

If yours says 2015 or earlier, keep reading. If it says 2022, flush it this fall and come back in a few years.

Why Arizona water shortens it

Chandler publishes an average of 16.5 grains per gallon, with a range of 5 to 20 across the city. Mesa runs 12 to 22 depending on which plant serves your street. Gilbert is the soft end of the East Valley at 8 to 10. The USGS calls anything over 180 mg/L "very hard," and using the 17.1 mg/L per grain conversion on Gilbert's own water page, Chandler's average works out to about 282 mg/L. Very hard, every day, for the life of the tank.

Two things happen inside. Minerals fall out of the heated water and pile up on the bottom of the tank as sediment. The burner then has to heat through that layer, so the tank runs longer, gets hotter at the bottom, and the steel there fatigues. At the same time the anode rod, a metal stick that's designed to corrode instead of the tank, gets used up faster in mineral heavy water. Once it's gone, the tank corrodes in its place. A. O. Smith calls hard water the biggest threat to a water heater's life. Rheem lists it first among the things that speed up wear.

What stretches it

Flush the tank once a year. Hook a hose to the drain valve, run it outside, and let the sediment out until the water runs clear. On a tank that's never been flushed, go easy the first time. The drain valve may not want to close again.

Have the anode rod checked. It unscrews from the top of the tank, and what's left of it tells you exactly how the tank is doing. If it's a bare wire, replace it. If the tank is past ten years, it's probably too late for a rod to help.

Check the pressure. A. O. Smith points out that high pressure stresses the system, and a failed pressure regulator lets full street pressure into the house. A cheap gauge on a hose bib tells you.

Add an expansion tank if you don't have one. Heated water expands, and with a closed system that pressure has to go somewhere. It's a standard code item on a new install.

Repair, or replace?

Repair when the tank is under eight years old and the problem is a part: a thermocouple, a heating element, a gas valve, a T&P valve, the drain valve. Replace when water is coming from the tank body, when the hot water runs rusty, when it's past ten years and needs a second repair, or when it's sitting in a hall closet or an attic and it's past its rated life. Rheem says the risk of a leak or sudden failure climbs a lot after year ten, and a garage tank that lets go is a mess while a closet tank that lets go is a claim. Pick the day. Don't let the tank pick it.

Permits come up here. Gilbert exempts a like for like swap when an Arizona licensed contractor installs it at equal or lower BTU or amperage, and it isn't tankless. Do it yourself, go bigger, or go tankless, and you're pulling a permit. Gilbert's residential plumbing permit is $150. Other cities have their own rules.