A building round tells somebody to look at the water heater. It does not say what the water heater's own list contains, and that is where these assets are lost: the work is small, mostly annual, usually done by whoever is passing, and almost never recorded against the asset. Three assets sit together here and fail in three different ways. A storage heater fails through corrosion and sediment. A tankless unit fails through scale. A softener fails silently, by quietly stopping.
What a water heater maintenance checklist must not leave out
Four items, in order of consequence. Operate the temperature and pressure relief valve, because it is the safety device and the only one on the appliance; a list without it is not a checklist. Inspect the anode where the design has one, since it is the part that is deliberately consumed to protect the tank and a spent anode means the tank is next. Flush the sediment, which insulates the bottom of a gas-fired tank from its own burner and is the reason an old heater takes longer for less. And on gas units check the flue and the combustion, which is qualified work under rules set elsewhere rather than a round item.
The tankless water heater maintenance checklist is a different list
No tank means no anode and no sediment to flush, so two of the four items above do not apply. What replaces them is scale: a tankless unit heats water across a narrow heat exchanger, and mineral deposit there is what takes its output down. So the tankless water heater maintenance checklist is descaling, the inlet screen or filter, the venting, and the condensate trap on a condensing unit. Its interval is set by the water rather than by the calendar, which is the awkward part of planning it: two identical units on different supplies do not want the same date.
The water softener maintenance checklist: salt, brine and resin
Water hardness is the amount of dissolved calcium and magnesium in the supply, and a softener exchanges those minerals out. Its checklist is therefore about whether the exchange is still happening: the salt level and whether it has bridged into a crust over an empty space, the brine draw, evidence that regeneration ran, the bypass valve exercised so it works when a plumber needs it, and a hardness reading downstream. That last item is the whole point, because a softener that has stopped regenerating looks exactly like one that is working until the appliances it protects begin to scale.
Where these sit on the plumbing preventive maintenance checklist
The building round and the asset list do different jobs, and conflating them is why both get abandoned. The round's job is to notice: is there water where there should not be, is the salt low, is anything weeping. The asset's own list is what a visit runs, and it belongs attached to the asset rather than to the round, because it is longer, it is annual rather than monthly, and it changes with the model. Keep the round short enough that it actually gets done every month, and let each of these three assets carry its own list and its own record.
Questions people ask about water heater maintenance checklist
Why is the relief valve the item a water heater maintenance checklist cannot skip?
Because it is the appliance's only safety device. Everything else on the list protects the tank or its efficiency; the temperature and pressure relief valve is what stands between a failed thermostat and a pressure vessel, and it is a device that spends years untouched.
How often should a tankless unit be descaled?
On an interval set by the hardness of the supply rather than by the calendar, with the manufacturer's figure as the starting point. That is why two identical units in different buildings should not share a date, and why a hardness reading is worth taking before the interval is written down.
How do you tell that a water softener has stopped working?
By a hardness reading downstream of it. Salt going down and a regeneration cycle running are the two things to look for on the round, but the reading is the proof, because a unit that has stopped exchanging looks no different until scale appears in the appliances behind it.