The four that prevent the expensive failures
If the rest of this list never happens, do these.
Turn the main shutoff off and on — once a year. Valves seize from disuse. Discovering that during an emergency, with water coming through a ceiling, is the worst version of every plumbing problem. Do the stops behind toilets and under sinks at the same time; thirty seconds each.
Run the meter test — twice a year. Shut off everything that uses water, check whether the meter's flow indicator is moving, and if not, compare readings an hour apart. It catches silent leaks — a seeping toilet flapper, an irrigation valve that never fully closes, a slab leak in its early stage. Full method in finding a hidden leak.
Flush the water heater — annually. On 15-30 grain water, sediment builds on the tank floor, insulates the burner and costs both efficiency and usable capacity. A tankless unit needs its descaling flush on the same schedule, or twice a year on a well.
Disconnect and drain hoses — before winter. Water trapped in a hose freezes back into the bib and splits it, often inside the wall. Five minutes, and it prevents the most common freeze failure in the area.
Worth knowing
Three of those four are about finding a problem early rather than fixing one. That is the whole principle here: plumbing failures are rarely sudden, and the cost difference between catching one early and finding out late is usually an order of magnitude.
Monthly, and quick
Run water in unused fixtures. Guest bathrooms, utility sinks, floor drains. Traps evaporate dry, and a dry trap lets sewer gas into the house — the most common cause of a mystery smell, and one that is solved in thirty seconds.
Look under sinks with a torch. You are checking for the slow drip that has been going for months, and for white mineral crust, which marks a leak that evaporates between visits.
Clear hair catchers. Unpleasant for a few seconds, and it prevents more drain calls than anything else.
Check the water heater's surroundings. Not for a puddle — you would have seen that — but for rust streaks or a dried white trail down the side. Those are the earliest physical warning a tank gives.
Twice a year
Test the water heater's T&P relief valve. Lift the lever briefly and let it snap back. Water should discharge and stop cleanly. Nothing coming out, or a valve that will not reseat, needs attention — it is the one component whose failure is genuinely dangerous.
Check water pressure with a gauge on an outdoor hose bib. 50-75 psi is healthy; above 80 is quietly destroying appliance valves and supply hoses. Take a reading overnight too, when municipal pressure often rises. See high water pressure.
Test any sump pump by pouring water into the pit rather than lifting the float by hand.
Clean showerheads and aerators in vinegar. On our water this is the actual cause of most “low pressure” complaints at a single fixture.
Annually
Backflow preventer test if you have irrigation — it is a legal requirement in Texas, not an optional service. Test in spring so freeze damage is found before irrigation season.
Check the softener's salt and settings. A unit regenerating far more often than expected is usually undersized or set to the wrong hardness figure.
Check the pressure tank air charge if you are on a well — it should read 2 psi below the pump's cut-in pressure. A waterlogged tank destroys pumps.
Walk the irrigation system while it runs, looking for broken, sunken or misaligned heads. It operates when nobody is watching, which is why these go unnoticed for months.
Replace washing machine hoses if they are rubber. Braided stainless costs little and rubber hoses are among the most common causes of domestic water damage — they fail as a burst, not a drip.
Seasonal, because our year has two pressure points
Before winter — hoses off, exposed pipe insulated in attic, garage and crawl space, irrigation drained, backflow assembly covered, and draughts sealed where pipes pass through exterior walls. The full version is in the fall checklist.
Before summer — irrigation checked and adjusted, water heater flushed before it faces heavy demand, and the meter test run before irrigation season makes a leak impossible to distinguish from usage.
Those two windows account for most of the seasonal failures here. Our freezes are short, sharp and arrive after mild weather, and our summers put the irrigation system under load for months.
What is not worth your money
Being straight about this, because plenty is sold as maintenance that is not.
Routine chemical drain treatment. It does not prevent the blockages that matter, and repeated use damages older pipe and rubber seals. A hair catcher and not pouring grease down the sink achieve more.
Annual drain cleaning with no symptoms. If the drains run freely and nothing has backed up, there is nothing to clean. Respond to the early signs instead — slowing, gurgling, more than one fixture.
“Whole-home inspections” sold on a subscription with no findings. An inspection is worth it when buying, selling, or after a symptom. Paying for one every year on a house you know is different.
Replacing a water heater purely on age. Twelve years is a reasonable point to start planning, not an expiry date. A sound tank with no rusty water and no leak has time left, and we will say so.