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Water heater maintenance: the schedule worth keeping.

A tank water heater lasts 10–15 years; tankless can run past 20. The difference between the low end and the high end is mostly maintenance nobody remembers. Here is the actual schedule, what forgetting costs, and the signs you are overdue.

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Last reviewed June 10, 2026. Sources linked inline and listed at the bottom. TextMyHouse sends reminders; it does not perform maintenance. Follow your manual or call a qualified plumber when unsure.

Tank flush1×/year · every 6 months in hard water
T&P valve test1×/year
Anode rod checkEvery 3–5 years
Lifespan stakes
10–15 yrs

Typical storage water heater life per the U.S. Department of Energy. Tankless: 20+.

9:41
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Reminder: it's been a year since your last water heater flush. 30 minutes now beats a cold shower in January. Reply DONE, LATER, or WHY.
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Logged. Nothing else due on the water heater until the valve test next spring.
Quick answer

Four tasks. Once a year covers most of it.

Flush the tank yearly, test the relief valve yearly, check the anode rod every few years, descale tankless annually. That is the whole job.

✓Flush a tank water heater once a year — every six months in hard-water areas, where sediment builds roughly twice as fast.
✓Test the temperature & pressure (T&P) relief valve once a year. If it drips afterward, it needs replacement.
✓Check the anode rod every 3–5 years — sooner with a water softener, which speeds anode wear.
✓Descale a tankless unit about once a year, per manufacturer guidance — more often in hard water.

The maintenance schedule

Every interval below comes from U.S. Department of Energy or manufacturer guidance — adjust for your model using the manual. TextMyHouse times these to your specific setup: tank or tankless, your water, your climate.

TaskHow oftenWhoWhy it matters
Flush sediment from the tank1×/year
6 mo in hard water		Usually DIYSediment blankets the bottom of the tank, forcing the burner to heat through rock. Efficiency drops, the tank rumbles, and the floor of the tank overheats and wears out early.
Test the T&P relief valve1×/yearDIY with cautionThe tank's main safety device against over-pressure. Valves stick shut or weep with age. Lift the lever briefly; if it keeps dripping after, replace it.
Check the anode rodEvery 3–5 yrsDIY or proA sacrificial rod that corrodes so the tank lining doesn't. Once it's consumed, the tank itself starts rusting from the inside — that's the beginning of the end.
Verify temperature is set to 120°FOnce, then after any changeDIYThe DOE-recommended setting: reduces scald risk, slows mineral buildup, and trims standby losses on the roughly 18% of home energy that goes to water heating.
Descale a tankless unit1×/yearPro or experienced DIYNo tank, but mineral scale coats the heat exchanger — especially in hard water. Needs isolation valves and a pump kit; if your install lacks them, this is a plumber visit.

What forgetting costs

The annual flush costs you 30 minutes and nothing else. Here is the other side of the ledger.

$1,339

Average cost to replace a tank water heater ($882–$1,817 typical range), per Angi's 2026 cost data.

$2,638

Average installed cost of a tankless unit, per Angi — what a neglected heat exchanger puts at risk.

$13,954

Average homeowners insurance claim for water damage and freezing (2018–2022), per the Insurance Information Institute. A failed tank is one common way to file one.

~18%

Share of a typical home's energy that goes to water heating — the second-largest energy expense in the house, per the U.S. Department of Energy. Sediment makes that line item quietly grow.

Signs you're overdue

!Rumbling or popping while heating. Water trapped under the sediment layer is boiling. The fix is a flush; the sound is the warning.
!Rusty or metallic-smelling hot water (cold runs clear). The anode rod is likely consumed and the tank has started corroding.
!Moisture or drips around the base or the T&P discharge pipe. Don't wait on this one.
!Hot water runs out faster than it used to. Sediment is occupying tank volume and insulating the burner.
!The unit is 10+ years old and has never been serviced. It's at the age where the DOE lifespan range starts ending; maintenance now still buys time.
!A tankless unit cycling or showing scale error codes. Time to descale.

How to flush a tank in 30 minutes

Turn the thermostat to pilot (gas) or cut power at the breaker (electric). Close the cold-water inlet. Connect a garden hose to the drain valve at the base and run it to a floor drain or outside. Open a hot tap upstairs to break the vacuum, open the drain valve, and let it run until the water comes out clear — usually 10–20 minutes. Close the valve, refill, then restore power only after the tank is full.

That's the whole task. If the drain valve won't open, don't force it — old plastic valves snap, and a snapped valve is an emergency. That's the line where DIY ends.

DIY or call a pro?

Usually fine yourself

Flush, temperature check, visual inspection

Annual sediment flush with a garden hose, verifying the 120°F setting, and looking over fittings for moisture are homeowner tasks on most units.

Use caution

T&P valve test, anode rod

Test the valve briefly and stop if it drips afterward. Anode rods are often seized — if it doesn't break loose with reasonable force, hand it to a plumber with an impact wrench.

Call a pro

Gas, corrosion, leaks, stuck parts

Gas smell, active leaking, visible rust on the tank body, snapped or seized valves, or tankless descaling without isolation valves. Stop and call.

Questions homeowners ask

How often should a water heater be flushed?

Once a year for tank units. In hard-water areas, every six months — sediment builds roughly twice as fast. Tankless units should be descaled about once a year.

How long does a water heater last?

The U.S. Department of Energy puts storage water heaters at 10–15 years and tankless at more than 20. Maintenance is the main lever that decides which end of the range you get.

What is the T&P valve and how often should I test it?

The temperature and pressure relief valve is the tank's main safety device — it releases water if the tank overheats or over-pressurizes. Test it once a year by briefly lifting the lever. If it keeps dripping afterward, it needs replacement: call a plumber.

What does it cost to replace a water heater?

Per Angi's 2026 data, a tank replacement runs $882–$1,817 (average $1,339); a tankless unit averages $2,638 installed. The annual DIY flush that delays that bill costs nothing.

What is an anode rod?

A sacrificial metal rod inside the tank that corrodes first so the tank lining doesn't. Check it every 3–5 years — sooner if you have a water softener. Once the rod is consumed, the tank itself starts rusting.

Does TextMyHouse perform the maintenance?

No. TextMyHouse sends SMS reminders timed to your setup — tank or tankless, your climate, your water — so these tasks actually happen.

Related guides

Sump pump testingThe other appliance that fails quietly and floods loudly. HVAC filter changesThe most frequent recurring task in the house. Gutter cleaningSeasonal water control, before it reaches the foundation.

Sources

Last reviewed June 10, 2026. Systems vary by model, age, water hardness, climate, and manufacturer guidance — when this page and your manual disagree, the manual wins.

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