Almost every expensive plumbing failure gives warning first. The trouble is that the warnings are quiet, and nobody's looking.

Ten minutes a month catches most of them while they're still small. Here's the walkthrough.

Under every sink

Open the cabinet and look with a flashlight. You're checking for damp, staining, or a white crust of dried mineral deposit — that last one means a slow leak that's been evaporating, which is easy to miss and worth catching.

Run your hand along the supply lines and the trap. Anything damp gets investigated now, not later.

Behind and around toilets

Check the floor at the base. Damp there usually means a failed wax ring, and that leaks into the subfloor where you can't see it accumulating.

Push gently on the bowl. Any rocking means the flange or ring needs attention before the seal fails properly.

The water heater

Look at the base for moisture, rust streaks, or pooling. See our water heater service. Check that the seismic straps are intact and tight — required in California and genuinely important here.

Listen while it's heating. Rumbling or popping means sediment, which is worth flushing before it does damage.

Test a drain properly

Fill a sink completely, then release it and watch. A healthy drain empties with a steady vortex. Slow draining, or gurgling from another fixture nearby, is an early signal worth acting on.

Exterior fixtures

Particularly relevant in Daly City. Operate each hose bib fully open and fully closed. Check for drips after closing and for corrosion at the fittings.

Valves that get exercised seize far less often, and marine air means exterior components here need more attention than they would inland.

Read the meter

The single most useful test on this list. Turn off every fixture and appliance that uses water, then check the meter's leak indicator — usually a small triangle or dial.

If it's moving with everything off, water is going somewhere. That's a leak — see leak detection — and finding it early is enormously cheaper than finding it through a water bill or a damaged floor.

The meter test takes two minutes and catches leaks nothing else will — slab leaks, underground irrigation leaks, and running toilets that are too quiet to notice. If the indicator moves with everything off, call.

Quarterly additions

  • Operate the main shut-off valve fully closed and open, confirming it works
  • Clear debris from yard drains and gutter downspout connections
  • Check crawlspace or under-floor areas for damp, particularly after heavy rain
  • Test the sump pump under actual load if you have one

Annually

  • Flush the water heater to clear sediment
  • Inspect the anode rod if the unit is more than five years old
  • Test water pressure — above about 80 psi stresses the whole system and shortens fixture life
  • Consider a sewer camera inspection if you have mature trees near the lateral run

Worth your time

  • The monthly meter test — catches invisible leaks
  • Exercising valves so they don't seize
  • Flushing the water heater annually
  • Investigating any new sound the plumbing makes

Skip these

  • Chemical drain cleaners as routine maintenance
  • Ignoring a small drip because it's small
  • Assuming a valve works without testing it
  • Waiting for a bill to tell you about a leak

The point of all this

None of these checks require tools or expertise. They just require looking, on a schedule, at the parts of the house that quietly go wrong.

A slow leak found in month one is a washer. Found in month eighteen, it's a subfloor.