No tools · about twenty minutes
How to prove you have a leak, and roughly where, with a water meter
Two tests. The first says whether water is moving when nothing is running. The second says whether it is moving inside the building or out in the yard, which is most of the diagnosis.
- CFC1433655Florida plumbing contractor license
- Two testsone proves it, one places it
How do I know whether I actually have a leak?
Turn everything off and watch the meter. Close every tap, stop the washing machine and the dishwasher, do not flush anything, and make sure the irrigation is not due to run. Then open the meter box at the front of the property and look at the dial.
Most meters have a small triangular or star-shaped indicator that spins on any flow at all, however small. If it is moving with nothing running in the house, water is leaving the system somewhere. If there is no such indicator, write down the reading, wait twenty minutes with nothing used, and read it again. A number that changed is a leak.
That test costs nothing and it converts a suspicion into a fact, which matters because the alternative is paying somebody to look for a leak that may not exist.
The second test
Inside the house, or out in the yard?
Once the meter has told you there is a leak, the next question is worth far more than it costs to answer: is the water escaping inside the building, or in the buried run between the meter and the house? Those are very different jobs, and on a large lot they are very different amounts of digging.
Close the house valve
Find the shut-off where the supply enters the building, on an exterior wall or in a garage or utility area, and close it. Leave the meter valve open. Now go back and watch the meter again.
- The meter is still moving. The leak is upstream of the house, in the buried service run between the meter and the building. That is the classic South Florida acre-lot leak: it never appears indoors, it never stops, and the bill is the only thing that reports it.
- The meter has stopped. The leak is inside the building or under its slab. That narrows the search enormously and it is the point at which acoustic listening, thermal imaging and pressure testing earn their keep.
Why this matters more here than elsewhere
In a region with no basements, almost every house is slab-on-grade, and the water table is shallow. Water leaving a pressurized line under concrete does not pool at the break: it travels through the fill until it finds a seam, a crack or the lowest point in the floor, and that is where it appears. So the damp patch is evidence of travel rather than a location, and the meter is often the only honest instrument a homeowner has.
What the test cannot tell you
It cannot find the leak. It tells you there is one and which side of the house valve it is on, which is genuinely most of the useful information, but locating a break under a slab still needs equipment. It also will not see a drain leak, because a drain is not pressurized and does not pass the meter.
Two things that fake a leak
Irrigation on a timer is the commonest false positive: if it runs during your twenty minutes, the meter moves and nothing is wrong. A toilet flapper that does not seat is the second, and it is a real leak but a cheap one, so check the toilets before assuming the worst.
Questions
Common questions about the meter test
How small a leak will the meter show?
The small spinning indicator most meters carry is designed to move on very low flow, so it will usually catch something too small to hear. If your meter has no such indicator, the twenty-minute reading comparison catches anything worth acting on.
My meter moved but I cannot find any water. Where is it?
If it kept moving with the house valve closed, it is in the buried run outside. If it stopped, it is inside or under the slab, and in this region that usually means it is traveling through fill and surfacing somewhere unrelated to the break.
Could it be the pool or the irrigation?
Very often, and both are worth ruling out first. They are separate pressurized systems and both get tested the same way, so it is a genuine possibility rather than a way of avoiding the question.
Does this work for a drain problem?
No. A drain is not under pressure and does not pass through the meter, so nothing about a blocked or broken drain will show up in this test. That is a camera question rather than a meter one.
Related
What this connects to
Where the meter test usually leads.
Live dispatch · 24 / 7 / 365
Meter moving with everything off?
That is a leak, and you now know which side of the house it is on. A person answers at any hour and the next step is locating it.
No obligation. Work performed under Florida plumbing contractor license CFC1433655.