Follow the heater's maintenance schedule for sediment, anode inspection and relief-valve service. Check water pressure, required expansion control and leaks. Water quality and temperature affect wear, but no study gives a guaranteed extra lifespan for your household. Use the actual model's instructions.
How long should a water heater last?
Expect roughly 8 to 12 years from a tank, with real variation. A. O. Smith says that figure is based on the manufacturer's suggested service life and varies with location, design, installation quality, maintenance and water quality. A Pacific Northwest National Laboratory report prepared for the U.S. Department of Energy gives a wider band, saying water heater life is generally 8 to 20 years depending on type, water quality and maintenance.
The report reviews earlier literature and identifies water quality as an important influence. It is not a field study predicting the life of each Phoenix household's heater.
What should your maintenance checklist cover?
| Item | Task | How often |
|---|---|---|
| 1 | Flush sediment | Follow the model; cited A. O. Smith guidance recommends at least yearly |
| 2 | Inspect the anode rod | Per your manual, sooner with a softener |
| 3 | Set the thermostat to 120F | Once, then recheck |
| 4 | Relief-valve service | Follow the model; use a qualified professional where required |
| 5 | Check pressure and expansion | Follow the installation and maintenance instructions |
| 6 | Keep a drain pan and clear space | Once, then look |
Why flush the tank first?
Sediment is one maintenance concern. The EPA's WaterSense program says to flush the heater once a year to reduce sediment buildup that can decrease efficiency. A. O. Smith says tanks need flushing at least once a year and that hard water may call for more. PNNL discusses scale and sediment while reviewing prior studies. Its 25 to 40 percent longevity figure comes from a cited consumer article, not a measured universal household service-life loss; it should not be used to predict when your heater will fail. For the Phoenix interval and reasoning, see how often to flush a water heater in Phoenix. For the hands-on steps, use our drain and anode rod guide.
How often should the anode rod be checked?
Check it on the schedule in your own manual, because the makers differ. A. O. Smith's maintenance guide says at least every three years depending on local water conditions, and yearly with a softener. Bradford White's manual says every 2 years, and that a softener may speed up consumption. PNNL reviews concerns about softened water and anode consumption, but that does not establish a universal percentage reduction in tank life. Use the heater maker's inspection and replacement criteria.
That is why softeners deserve a second look. Our pages on salt-based softeners and water heaters and hard water and water heaters explain the tradeoff. Rheem's manual is blunt about one thing: do not remove the anode rod, since operating without it greatly shortens tank life and excludes warranty coverage.
What temperature setting protects the tank?
Set it to 120 degrees Fahrenheit unless you have a reason not to. The Consumer Product Safety Commission urges users to lower their water heaters to 120 degrees. PNNL presents a calculation from earlier work, not a household field measurement: with water at 170 mg/L hardness, 0.06 inches of scale could build up in about 4 years at 140F in a 50-gallon tank drawing 66 gallons a day, but it would take almost 30 years at 120F. The calculation illustrates temperature sensitivity under its assumptions; it is not a timetable for your tank. See what temperature to set a water heater for the full picture.
Should you test the relief valve?
Follow your model's schedule and service instructions. The cited Rheem hybrid manual says to lift and release the lever on the temperature and pressure relief valve to make sure it operates freely, and to let several gallons flush through the discharge line to an open drain. Bradford White warns that hot water is released under pressure, so stand clear. Never plug the valve's outlet. Do not operate it if its discharge cannot be safely directed or the instructions require a qualified technician.
If it drips afterward or on its own, do not just swap it. A. O. Smith's guide says a dripping T&P valve often means high water pressure or thermal expansion on a closed system, and to fix those first. Our page on a leaking relief valve covers the causes.
Do you need to control pressure and expansion?
Often, yes. A. O. Smith's guide says to check pressure at a hose bib, install a pressure reducing valve if it is above the code maximum of 80 psi, and provide appropriate thermal-expansion control on a closed storage-heater system. A properly sized expansion tank is a common solution, but the model and applicable code decide the required arrangement. It says most experts recommend setting the pressure reducing valve to 50 to 60 psi. Our expansion tank page explains how to tell if your home is a closed system.
What else helps a tank last?
- Drain pan. Bradford White's manual calls for a drain pan piped to an adequate drain where a leak could damage the area below. See water in the drain pan.
- Clear space. No flammables near the heater, per the same manual.
- Know your limits. A. O. Smith says to connect with a certified local contractor if you're not comfortable doing maintenance yourself, and it lists burner and combustion checks on gas models as annual technician tasks.
- Tankless units. A. O. Smith says tankless heaters need descaling rather than flushing. PNNL describes an earlier accelerated tankless test with artificially prepared 444 mg/L hardness, 140°F operation and heavy draws. Scale caused blockage after about 1.6 equivalent test years and the unit was delimed. That simulated result does not mean an ordinary household heater needs replacement in under two calendar years. See descaling a tankless heater in Phoenix.
What about Phoenix heat and hard water?
Phoenix has very hard water, and many heaters sit in hot garages or attics. We cover the heat side in whether Arizona heat damages water heaters and pipes. The practical answer is the same list, done on time. If the tank is past 10 years and leaking at the base, weigh repair versus replacement.
HQ is licensed and insured, and gives free estimates and upfront pricing before work starts.