Why it works
Why the Meter Test Works
The meter records water passing into your plumbing. If every fixture and appliance is off, it should stay still.
Movement with everything off suggests water is escaping somewhere. That could be a toilet, a dripping fixture or a hidden pipe.
The test does not show where the leak is. It tells you whether to keep investigating.
Before you start
Before You Start
Meters vary by age and manufacturer. Yours may have a dial, a digital display or both.
- Find your meter. In many homes it is in the basement, a utility room or a closet near where the water line enters.
- Note any shutoff valves on either side of the meter.
- Do not remove covers, loosen fittings or try to adjust the meter.
- If the meter is hard to reach or the area is wet and near electrical equipment, stop and get help.
Reading the meter
What to Look For on the Meter
Many meters have a small low-flow indicator. It may be a triangle, star, small wheel or flashing symbol that moves even with slow flow.
Most meters also show a running total, like a car odometer. Some digital meters display a flow rate or alert icon.
If you are unsure how your model works, the manufacturer’s label or your utility can help you read it.
Step-by-step test
Step-by-Step Meter Leak Test
- Turn off every faucet, shower and outdoor spigot.
- Make sure the dishwasher, washing machine, ice maker and water softener are not running or regenerating.
- Wait a few minutes so any refilling tank finishes.
- Look at the low-flow indicator. Note whether it is moving.
- Write down or photograph the full meter reading.
- Leave all water off for at least 30 minutes, longer if you can.
- Read the meter again and compare.
A slow leak may only show up over a longer test. Some people take an evening reading and a morning reading with no water used overnight.
Toilets first
Narrowing It Down: Toilets First
Toilets are a common source of silent water loss. Before suspecting a hidden pipe, rule them out.
- Put a few drops of food coloring in each toilet tank.
- Wait 15 to 30 minutes without flushing.
- If color appears in the bowl, that toilet is leaking internally.
If a toilet connection or shutoff is dripping, see our page on fixture and supply line leak repair.
Main shutoff
Narrowing It Down: Your Main Shutoff
If your home has a main shutoff valve on the house side of the meter, it can help separate inside and outside leaks.
- Close the house-side shutoff gently. Do not force a stiff valve.
- Watch the meter’s low-flow indicator.
- If it stops, the leak is likely inside the house.
- If it keeps moving, the leak may be between the meter and that valve, or at the meter itself.
Valve layouts differ. If you are unsure which valve is which, don’t guess.
Reading results
How to Read Your Results
| What you observe | What it may mean | Suggested next step |
|---|---|---|
| Indicator still, reading unchanged | No measurable leak during the test | Recheck monthly or if your bill changes |
| Indicator moves, toilet dye test positive | Toilet is leaking into the bowl | Repair the toilet, then retest |
| Indicator moves, stops when house shutoff is closed | Leak is likely inside the home | Check fixtures, then consider hidden water leak detection |
| Indicator moves even with house shutoff closed | Leak may be near the meter or on a line before that valve | Check meter fittings, then see the responsibility notes below |
| Wet or sinking ground along the water line route | Possible buried line leak, which an indoor meter may not register | Read about underground water line leaks |
| Water dripping at the meter itself | Possible leak at the meter connections | Contact the City Water Utility |
| Condensation on the meter, nothing moving | Normal sweating, not a leak | No action needed |
What the city says
What the City Says About Meter Leaks
The City of Naperville notes that water meters usually don’t leak unless they are disturbed. It also says condensation on a meter is normal.
The City suggests checking your meter for leaks at least monthly. It recommends checking more often if the meter is in a closet or other enclosed space.
According to the City, it repairs leaks between the two spud nuts, which are the fittings connecting the pipes on each side of the meter. Other leaks in that meter context are the homeowner’s responsibility.
Buried service-line ownership is described separately, in our Naperville water line responsibility guide. Read the City’s water meter leaks page for current details.
City or private
City Utility or Private Plumbing?
If water is leaking right at the meter connections, the City is the right first contact. If you are unsure of the source, the City’s page lists the Department of Public Utilities–Water at (630) 420-6137.
If the meter is dry but shows flow, the leak is most likely on the property side. That points to fixtures, interior pipes or any piping past the meter.
For a fuller explanation of boundaries, see Naperville water line responsibility.
Exceptions
Exceptions That Can Confuse the Test
- Water softeners and filters can use water during regeneration cycles.
- Refrigerators with ice makers may refill without warning.
- Irrigation systems on timers can start during a test.
- A slow toilet refill can look like a constant leak.
- Some digital meters update their display on a delay.
- If your meter is inside the house, a leak on the buried line before it may not show on the meter at all.
Pause or bypass these where you safely can, then repeat the test.
FAQ
Frequently Asked Questions
How long should a meter leak test last?
At least 30 minutes is a reasonable start. Very slow leaks may need several hours, such as an overnight test with no water use.
My meter has no moving indicator. Can I still test?
Yes. Compare two full readings taken some time apart with no water used. Any change suggests flow.
Can a leak be too small to show on the meter?
A very slow leak may take a long time to register. Repeating the test over a longer period helps.
Should I close the shutoff on the street side of the meter?
Avoid operating valves you are unsure about. If the question involves the meter or utility-side valves, contact the City Water Utility.
Next steps
Next Steps
More guides on reading leak clues are in our water leak guides. If your test points to a private-side leak you can’t find, a professional investigation is the next step.