DIY Whole-Home Leak Audit: A 30-Minute Checklist

A water bill that jumped is one of the most common reasons homeowners call us, and roughly half the time the answer is something the homeowner could have found themselves in thirty minutes. Here is the sequence, in the order that eliminates the most possibilities fastest.

This is the master test and everything else depends on it.

1. 1Turn off every water-using fixture and appliance in the house. Dishwasher, washing machine, ice maker, humidifier, everything.
2. 2Find your water meter — usually in a box near the front property line.
3. 3Look for the low-flow indicator: a small triangle, star or dial that spins on very small flows. It is more sensitive than the main dial.
4. 4Watch it for two full minutes.

If it does not move: you have no active leak on your side of the meter right now. Your bill increase is either usage, an intermittent leak like a toilet that only runs sometimes, or a billing issue. Skip to step 3 anyway — intermittent toilet leaks are common.

If it moves: water is going somewhere. Continue.

Shut off the irrigation system at its valve, then re-check the meter.

If the movement stops: your leak is in the landscape lines — a cracked drip lateral, a failed valve, a broken emitter. On gravel-landscaped lots that can leak for months without surfacing. Common on the larger lots in Pecan Creek, Bella Vista Farms and Taylor Ranch.

If it keeps moving: the leak is in the house or the buried supply line.

This is where the most common answer lives.

1. 1Put several drops of food coloring in each toilet tank.
2. 2Do not flush for twenty minutes.
3. 3Check each bowl for color.

Color in the bowl means water is leaking past the flapper — silently, continuously, and onto your bill. In 15 to 18 grain water this is the single most common cause of an unexplained increase, and homes frequently have two doing it at once.

The durable fix is not just a new flapper. The flush valve seat mineralizes too, so a fresh flapper sealing against a rough seat fails again within months — see running toilet: the hard-water fixes that actually last.

• Under every sink — dampness, corrosion or mineral crust at the angle stops and supply connections.
• Behind every toilet — the supply line and stop.
• The water heater — standing water in the pan, or dripping from the T&P discharge line.
• The softener — water around the base, or a drain line running when it should not be.
• Washing machine hoses — bulging, stiffness or rust at the connections.
• Every hose bib — weeping at the stem when closed.
• Ceilings below any attic plumbing — staining or discoloration.

If the meter is moving, irrigation is off, every toilet passed the dye test, and nothing visible is leaking, then the water is going somewhere you cannot see. That means one of:

• A slab leak — a failed line under the foundation. Look for a warm floor spot, a hairline crack in tile, or the sound of running water at night. See slab leak warning signs.
• An in-wall leak — a supply line inside a wall cavity, often showing as a damp baseboard or bubbling paint.
• A buried yard-line leak between the meter and the house, which on larger lots can run invisibly for months.

Call once you have a moving meter with no visible cause. At that point you need instruments — acoustic listening, thermal imaging, line tracing — and guessing gets expensive fast. See slab leak detection and emergency leak service.

Run this audit twice a year, and always in May before monsoon season. Ten thousand gallons a month can disappear under a slab without a single visible drop, and the earlier you catch it the smaller the whole problem stays. Seasonal owners in Sun Lakes and the retirement communities should run it before departing and again on return.