Ask plumbers what they argue about and the list runs long. Ask where a water system actually fails, and the answers converge almost word for word: not in the middle of a length of pipe, but at a joint.

You start a load before leaving for the day, the way you always do, and come home to water working its way under the laundry closet door.

A coil of PEX comes off the truck bound in a tight roll, and before any of it goes into a wall, somebody walks it out along the driveway to pull the coil memory out of the tube.

Replacing all the pipes in a home sounds drastic, so most people put it off, fixing one leak at a time. But there's a point where patching stops making sense — where the pipes themselves are wearing out, and the leaks are symptoms of a system at the end of its life. Knowing when a home has reached that point saves you from pouring money into endless repairs on pipes that are going to keep failing. Here's how to tell when it's time to repipe rather than repair.

The water heater sits quietly in a closet or garage until one day it starts popping, rumbling, or banging like there's something alive in there. The noise is unsettling, but it's also informative — water heaters make different sounds for different reasons, and most of them trace back to one common culprit. Knowing what the sounds mean tells you whether it's a simple maintenance issue or a sign the heater needs attention.

Reach into the cabinet under a kitchen sink with a pull-down faucet, and there is a hose disappearing up through the spout, with a plastic or metal weight clipped onto it partway down.

Somewhere on the water line under your kitchen sink, printed lengthwise along the tube in type about an eighth of an inch tall, is a line of text.

The most expensive leaks are the ones you can't see. A pipe inside a wall, under the slab, or beneath the floor can leak for weeks or months, quietly running up your bill and damaging the house, all without a visible drip. Because hidden leaks don't announce themselves, you have to know the indirect signs — the clues that water is escaping somewhere you can't see. Catching those early is the difference between a small repair and major water damage.

Fill a clear glass straight from the tap and hold it up to the light.

The vanity in the hall bathroom holds the usual inventory: a hair dryer with its cord wound around it, a basket of half-used bottles, a stack of towels somebody folded once, and a box nobody has opened since the move.

You reach down to unscrew the garden hose from the spigot, and instead of the hose letting go, the whole faucet turns with it.

Search for how long PEX plumbing lasts, and one claim turns up within a minute: that plastic supply pipe breaks down in chlorinated water, sometimes with several years attached, sometimes with a warning that a PEX repipe is already on a clock.

A toilet that rocks, smells or leaks at the base was usually set on a flange at the wrong height, on a wax ring of the wrong thickness or on an unlevel floor.

The handle is turned as far as it will go, and water is still finding a way out: a slow bead at the spout, or a damp patch seeping from underneath the handle itself.

Two houses stand on the same street, built the same year by the same builder, with the same rooms in the same order, the same bathroom at the same far corner of the plan.

You have already run the test without quite meaning to. Every other faucet in the house, from the bathroom sink to the tub to the hose bib outside, delivers a normal stream.

Shower valve installation plays a pivotal role in achieving spa-level comfort at home.

A cartridge sits on a paper towel on the counter, pulled from a faucet that would not stop dripping.

Turn the handle and water shows up right away, tracking down the base of the spout or beading along a seam near the handle.

Go up a pipe size, and the water pressure in the house goes up. That is the advice, repeated at hardware store counters and across half the search results on this subject, and it is wrong in a specific way worth knowing before anyone opens a wall.