Home plumbing maintenance checklist

What to check, and how often

The checks that cost nothing

Four minutes with a flashlight, four times a year, is the highest return maintenance in the house.

• Under every sink. Feel the trap and the supply lines rather than just looking. A slow drip evaporates between visits and leaves only a faint mineral line behind. A swollen or discolored cabinet base means it has been happening for a while.
• Around the base of every toilet. Rocking, damp, or a floor that gives slightly underfoot.
• Behind the washing machine and the dishwasher, which is where the hoses are and where nobody looks.
• The ceiling under any upstairs bathroom. A faint ring is the earliest visible sign of a leak above.
• The water meter, when the house is quiet. Turn everything off, note the reading, come back in an hour. Movement with nothing running is a leak somewhere you haven't found.

The water heater

The largest single container of water in the house, usually the oldest appliance, and the one most likely to end a day badly. Sediment, flushing intervals and the anode rod are all on the water heater page.

Two things are worth knowing regardless: the age of the unit, which is usually encoded in the serial number on the data plate, and where the water would go if the tank let go tonight.

There's a third worth being able to recognize, even if you never touch it. The temperature and pressure relief valve is the safety device that stops a heater becoming a pressure vessel, and it has a pipe running from it down toward the floor. That pipe should be dry, unobstructed, and running downward the whole way. It can end a few inches above the floor or above a floor drain with a visible gap between the two; what it must never be is threaded, capped, plugged, or routed uphill. A valve that drips, or a discharge pipe somebody has blocked, is a genuine problem and a same week call. Testing or replacing the valve itself is a plumber's job, because an old one that's lifted often won't reseat.

The sump pump, if you have one

A sump pump is the only thing on this page that has one job, does it rarely, and is catastrophic when it fails. It also sits in a damp pit doing nothing for months at a time, which is exactly the condition in which a float sticks.

Every three months, and again before the spring thaw, empty a five gallon bucket of water into the pit and watch what happens. Use the whole bucket: a typical pit is wide enough that a gallon or two barely covers the base and never lifts the float, which looks exactly like a dead pump and isn't. You're looking for four things: the float rises, the pump starts, the water level drops, and the pump shuts itself off. A pump that runs on after the pit is empty is as much of a problem as one that never starts.

• Check the float can move freely. A pump that has shifted on its base, or a float fouled by a cable or a wall, is the most common failure there is.
• Follow the discharge line outside and make sure the far end isn't buried, crushed or frozen shut. A pump working perfectly into a blocked pipe achieves nothing.
• Think about what happens in a power cut. Storms bring both the water and the outage, and a battery backup or a water powered backup is the answer to that particular coincidence.
• Listen for it cycling on and off rapidly. Short cycling usually means the pump is too big for the pit or the check valve has failed.

Water quality and pressure

• Clean the aerators and showerheads twice a year. Soaking in vinegar clears mineral buildup, though it can dull an oil rubbed bronze or unlacquered brass finish, so check what yours is before you leave one in overnight. Hard water means more often, and a single blocked aerator is the usual explanation for one tap that has gone weak while the rest are fine.
• Weak pressure everywhere at once is a different problem from weak pressure at one fixture, and worth saying that way when you describe it to somebody.
• Hard water is worth measuring rather than guessing. It changes how often almost everything on this page comes due, from the heater to the kettle.
• Check the incoming pressure once a year. A gauge that screws onto an outdoor faucet costs very little and reads it in seconds. Most houses sit somewhere in the 40 to 80 psi range; much above that is hard on every washer, valve and appliance in the building, and it shortens the life of the flexible supply lines faster than anything else. If yours reads high, there's usually a pressure reducing valve near where the main enters, and adjusting or replacing it is a plumber's job.

Fixtures nobody is using

Every drain in the house has a trap holding a little water, and that water is the only thing between the room and the sewer line. A trap that dries out stops sealing.

Run the guest bathroom, the basement sink, the floor drain and the utility tub once a month. It takes about ten seconds a fixture, and a dry trap lets sewer gas into the room.

The failures worth getting ahead of

What is a plumber's job

Anything involving the water heater's gas control, the flue, or a soldered joint. Anything behind a wall. A drain that keeps backing up after being cleared once, which is usually a sign of something structural rather than something in the trap. Any leak you can't see the source of.

And one that surprises people: a valve that won't reseat. A maintenance task that leaves water running and no way to stop it isn't a maintenance task any more, which is a good reason to know in advance who you'd call.

Patina keeps the four minute look under the sinks on a quarterly cycle. It's the cheapest job on this page and the easiest one to never get round to.