Most homeowners never look at their water heater until it fails. A 15-minute annual inspection can catch developing problems while they're still minor — before they become emergency replacements. Here is a 10-point checklist you can complete yourself with no tools required.
Find the data label on the side of the water heater and locate the serial number. Every major manufacturer encodes the manufacture date in the serial number. Search "[brand name] serial number date decoder" to interpret yours in 30 seconds. If your unit is 10 years or older, note it — this changes how you interpret everything else in this inspection. If it's over 12 years old, the question isn't whether to replace it but when.
Examine the floor around the base of the unit and the unit exterior carefully. Any rust-colored staining on the floor, water marks on the wall behind the unit, or visible rust weeping from the tank body indicates a slow leak or internal corrosion. This is a replacement trigger — do not ignore it.
Look at the two pipe connections at the top of the unit (one cold in, one hot out). White or greenish mineral deposits crusted around fittings indicate a slow seeping leak at the connection. This is typically a repairable problem — a plumber can retighten or replace the fitting — but left unattended, connection leaks worsen.
The T&P relief valve is typically on the side of the unit with a pipe running down from it. Check for: mineral buildup or rust on the valve body (may indicate age or previous weeping), water stains on the floor below the discharge pipe terminus, and that the discharge pipe is still connected and properly routed. A T&P valve showing rust or mineral buildup should be tested — see our T&P valve guide for the testing procedure.
If you have an expansion tank installed (a small football-shaped tank on the cold water inlet), tap it with your knuckle. It should sound hollow in the upper portion and more solid in the lower portion. If it sounds completely solid throughout, the internal bladder may have failed — the tank is waterlogged and no longer providing pressure relief. A waterlogged expansion tank costs $40–$80 to replace.
Run a hot water tap until the unit fires (you'll hear the burner ignite on gas or feel the current draw on electric). Listen for 2–3 minutes. Normal sounds: a soft whoosh of the burner, water movement. Concerning sounds: popping, rumbling, banging, or cracking noises that indicate sediment buildup on the tank bottom. Mild sounds may be addressed with flushing; severe sounds on an older unit suggest significant scale accumulation.
Trace the vent pipe from the draft hood at the top of the unit to where it enters the chimney or exits through the wall. Look for: rust spots or holes in the vent pipe, disconnected sections (a gap between pipes), improper slope (sections that run downhill), and proper clearance from combustible materials. Any holes or disconnected sections in the flue are serious and require immediate repair — combustion gases including carbon monoxide escape through them.
Confirm the gas shutoff valve on the supply line to the water heater is in the open position (handle parallel to pipe) and that you can physically access and operate it. In an emergency, you need to be able to shut off the gas quickly. If the valve is corroded, painted over, or hasn't been operated in years, consider having a plumber exercise and lubricate it during the next service visit.
If you've owned the unit for more than 5 years and the anode rod has never been inspected or replaced, add it to your maintenance schedule. The anode rod is the most underserviced maintenance item on tank water heaters and its condition directly determines how much longer the tank will last. See our anode rod guide for inspection details.
In California and other seismic zones, confirm two metal straps are installed — one in the upper third and one in the lower third of the unit — and that they are anchored through the unit's outer jacket to structural wall studs. Straps that are loose, corroded, or anchored to drywall only should be replaced. This is a code requirement that is also enforced at home sale in California.
If your inspection turns up one or more red flags — rust, leaks, flue problems, or a unit over 10 years old with sediment sounds — schedule a service call or a replacement evaluation. WaterHeaterMan offers same-day replacement in most service areas. Enter your address to get an exact installed price in under 60 seconds.
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