The Leaks You Never See Until the Bill Arrives
Published
Run the meter test, dye-test every toilet, then shut off irrigation for a day. Those three free steps find the large majority of household leaks. A running toilet alone wastes up to 200 gallons a day and is the most common cause by a wide margin.
Start with the meter, not the plumber
The meter test costs nothing and definitively answers whether water is leaving your system. Turn off every fixture and appliance, including ice makers and irrigation, read the meter, wait an hour using no water at all, and read again.
Most meters have a small triangular or star-shaped low-flow indicator that spins with even a trickle. With everything off, it should be completely still. Any movement means a leak.
Then check the toilets, because it is usually the toilets
A failed flapper is the single most common cause of an unexplained bill increase, and it is silent much of the time. Add a few drops of food colouring to each tank and wait fifteen minutes without flushing. Colour appearing in the bowl means that toilet is leaking.
The fix is a flapper costing a few dollars. The waste it prevents is up to 200 gallons a day.
Then irrigation, which hides in plain sight
Underground irrigation leaks produce no indoor symptom at all, and in a watered landscape the extra moisture goes unnoticed. Shut the system off entirely at its valve for a full day and watch the meter. If the loss stops, you have found it.
What is left is the expensive category
If the meter still moves after all three checks, the leak is hidden: inside a wall, under a slab, or in the buried service line between the meter and the house. That needs acoustic detection equipment, typically $350 to $800.
One useful refinement before you call: close your main shutoff and check the meter again. If it still moves with the main closed, the leak is between the meter and the house rather than inside it, which changes the repair entirely and is worth knowing before anyone quotes.