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Maintenance

Annual Water Heater Maintenance Checklist (Printable)

A complete yearly maintenance checklist for tank water heaters. Covers gas and electric models with seasonal timing and estimated costs.

Updated February 19, 2025
Editorially Reviewed • February 19, 2025
Annual Water Heater Maintenance Checklist (Printable)

Safety Disclaimer

Water heater maintenance involves working with pressurized systems, scalding hot water, and potentially hazardous electrical or gas connections. Always shut off power (electric heaters) or gas supply (gas heaters) and allow water to cool to a safe temperature before beginning any maintenance. Wear appropriate safety equipment including gloves and eye protection. If you're uncomfortable with any step, contact a licensed plumber.

Most water heaters sit in a basement or garage and get ignored until something goes wrong. That is understandable. They are not interesting appliances. But 30 minutes a year is the difference between a water heater that lasts 8 years and one that lasts 13.

I have put together this checklist based on what I do during residential service calls. Every task here is something a homeowner can handle with a garden hose, a wrench, and a bucket. No special training required.

The quick version

If you want the short list without the explanations:

TaskFrequencyTimeDIY cost
Flush the tankYearly (6 months if hard water)30-45 minFree
Test the T&P valveYearly2 minFree
Check the anode rodEvery 2-3 years15 min$20-50 if replacing
Inspect for leaksYearly5 minFree
Check the temperature settingYearly2 minFree
Clear the area around the heaterYearly5 minFree
Inspect the vent and flue (gas only)Yearly5 minFree
Listen for unusual soundsOngoing1 minFree

Total time commitment: about 1 hour per year. Total cost: $0 to $50 unless the anode rod needs replacing.

Task 1: Flush the tank

This is the single most important maintenance task. Sediment collects at the bottom of every tank water heater, regardless of your water quality. That sediment insulates the water from the heat source, makes the heater work harder, and shortens the tank’s life.

When: Once a year. Every 6 months if your water hardness is above 150 ppm (check your water utility’s annual report or buy a $10 test strip kit).

How: We have a complete walkthrough at How to Flush a Water Heater. The short version: connect a garden hose to the drain valve, run it outside or to a floor drain, open the valve, and let water flow until it runs clear. Three flush cycles usually does it.

Signs you’ve waited too long: Popping or rumbling sounds during heating, rusty-looking water from the hot side, or a noticeable drop in hot water volume. These are all signs your water heater needs flushing.

Task 2: Test the T&P (temperature and pressure) relief valve

The T&P valve is your water heater’s primary safety device. If pressure or temperature inside the tank exceeds safe levels, this valve opens to release water and prevent a potential rupture. If it is stuck closed, it can’t do its job.

When: Once a year.

How:

  1. Place a bucket under the discharge pipe (the pipe running from the valve down toward the floor).
  2. Lift the metal lever on the valve about halfway, hold for 3 to 5 seconds, and let go.
  3. You should hear water rush through the valve and see it exit the discharge pipe into the bucket.
  4. The valve should snap shut cleanly when you release the lever.

If no water comes out, or the valve drips continuously after you release it, replace the valve. A new T&P valve costs about $10 to $20 and threads in with a pipe wrench. For more details on T&P valve testing and safety, see our water heater safety guide.

Task 3: Check the anode rod

The anode rod is a metal rod suspended inside the tank that corrodes in place of the tank walls. It is the reason your steel tank does not rust through in three years. When the rod is consumed, the tank itself begins to corrode, and once that starts there is no reversing it.

When: First check at 3 years, then every 2 years after that. If you have a water softener or naturally soft water, check every 1 to 2 years because soft water is more aggressive on anode rods.

How: The rod threads into the top of the tank. You need a 1-1/16” socket and a breaker bar. Our full guide covers the process: When to Replace Your Anode Rod.

Replace it if: The rod is less than 1/2 inch in diameter at any point, or more than 6 inches of the core wire is exposed. A healthy anode rod is about 3/4 inch in diameter. A spent one looks like a thin wire covered in calcium.

Task 4: Inspect for leaks

A slow leak caught early is a hose clamp or a new fitting. A slow leak ignored for six months is water damage and mold remediation.

When: Every time you are near the water heater. Make a deliberate check at least once a year.

Where to look:

  • Top connections: Inspect the cold water inlet and hot water outlet pipes where they connect to the tank. Look for moisture, green corrosion on copper, or white mineral deposits on threaded connections.
  • T&P valve discharge pipe: Check for dripping. Occasional drips can indicate the valve is doing its job under thermal expansion. Constant dripping means the valve needs replacing or the system needs an expansion tank.
  • Drain valve: Make sure it is fully closed and not weeping.
  • Tank bottom: Look beneath and around the base of the tank. Any pooling water here could indicate a slow tank leak, a failed fitting, or condensation (which is normal on new tanks or after a cold-water refill).

If the tank itself is leaking (not a fitting or valve), the tank has corroded through and needs replacement. There is no patching a corroded tank. Our guide on how long water heaters last covers the decision-making process.

Task 5: Check the temperature setting

Factory defaults are often set to 140°F. The Department of Energy recommends 120°F. That 20-degree difference saves 6 to 10 percent on water heating costs, reduces scalding risk, and slows sediment formation.

When: Once a year, or after anyone else has accessed the water heater.

How: Check the dial on your gas control valve or electric thermostat panel. Then verify at the tap: run hot water at the closest faucet for 2 minutes and measure with a cooking thermometer. The dial setting and actual temperature often disagree.

Full details in our temperature settings guide.

Task 6: Clear the area around the heater

This is the task everyone forgets. Over the course of a year, boxes, paint cans, cleaning supplies, and holiday decorations tend to migrate toward the water heater. This matters for two reasons:

  • Gas water heaters need combustion air. A cluttered space restricts airflow and can cause incomplete combustion, which produces carbon monoxide. Maintain at least 12 inches of clearance on all sides.
  • Access for emergencies. If the water heater starts leaking at 2 AM, you need to reach the gas shutoff valve and the water inlet valve without climbing over storage bins.

When: Once a year. Treat it as a 5-minute task while you are already down there for the flush.

Task 7: Inspect the vent and flue (gas models only)

Gas water heaters produce combustion exhaust that must vent properly through the flue pipe and out the roof. A blocked or disconnected flue can send carbon monoxide into your living space.

When: Once a year.

What to check:

  • Flue pipe connections: Every joint should be secure and fully seated. Look for gaps, rust holes, or sagging sections.
  • Draft test: With the burner running, hold a match or lighter near the draft hood at the top of the heater. The flame should be drawn toward the hood (indicating proper updraft). If the flame blows away from the hood, you have a backdraft and need professional evaluation.
  • Roof cap: If accessible, check the vent cap on the roof for bird nests, debris, or damage.

For more on gas-specific maintenance, see our gas vs. electric maintenance guide.

Task 8: Listen for unusual sounds

This is the easiest “task” on the list. Just pay attention to what your water heater sounds like when it is heating:

SoundLikely causeAction
Popping/rumblingSediment on tank bottomFlush the tank
SizzlingCondensation dripping onto burner (gas)Normal on cold startups, concerning if constant
High-pitched whiningScale on electric elementFlush and inspect element
Ticking/tappingHeat trap nipples or pipes expandingNormal, no action needed
BangingWater hammer in pipesInstall a water hammer arrestor

Seasonal timing

The best time to do annual maintenance depends on your climate and usage patterns:

Spring (recommended): After winter heating season, when the heater has worked hardest. You flush out the sediment that accumulated during months of heavy use, and any issues are caught before summer when repair schedules are lighter and you can get a plumber within a day instead of a week.

Fall: Second-best option. Gets the tank clean before the heavy-use winter season. Some people prefer this because they want peak performance going into the months when they use the most hot water.

Avoid December through February if possible. Not because maintenance is harmful in winter, but because draining a tank into a frozen garden hose creates a mess, and plumber availability is worst during peak heating season if you discover a problem.

The 5-minute monthly check

If a full annual service feels like a lot, here is what to do monthly when you walk past the water heater:

  1. Glance at the floor around the base. Any water?
  2. Listen for rumbling or popping when the burner or element is on.
  3. Touch the pipes leaving the top of the tank. Hot water outlet should be warm. Cold water inlet should not be hot (if it is, the check valve may be failed and hot water is backflowing).
  4. Sniff. Rotten egg smell means the anode rod is reacting with bacteria. Gas smell means immediate action (ventilate, evacuate, call the gas company).

Four checks, 60 seconds, no tools.

Sources