Plumbing Advisors Editorial TeamEditorial StandardsSource review July 26, 2026Source-CheckedConfirm the pattern before opening walls or floors
Visible leak or unexplained water use?
With all indoor and outdoor water use off, movement on the meter's leak-detection gauge means water is still flowing. LADWP is clear that the gauge does not identify the source, so fixtures, irrigation, and hidden lines still need to be separated before access is planned.
A meter change or monitoring alert can confirm unexplained water use, but it cannot identify the leaking pipe or fixture by itself.
What the signs can tell you
Start with what you can observe: when the moisture appears, whether the meter changes with water off, and which fixture or area is nearby. Those details help narrow the search without guessing at a cause.
| What you notice | What it may indicate | What to do next |
|---|---|---|
| The meter changes while every fixture and appliance is off | Water may be escaping somewhere on the property | Record both readings and the time between them. A professional still needs to locate the source. |
| A stain or damp area grows after one fixture is used | The nearby fixture, supply, or drain path may be involved | Stop using that fixture and note how long it takes for the moisture to appear. |
| Water can be heard while nothing is running | A pressurized line or hidden fixture may still be using water | Check accessible fixtures and the meter without opening walls or floors. |
| The bill rises with no clear change in household use | An unidentified leak is one possible explanation | Compare the same billing period from the prior year and perform a no-use meter check. |
| Water is actively spreading through a wall, ceiling, or floor | The leak is ongoing and damage is increasing | Use a known safe shutoff if accessible, move away from the wet area, and request prompt help. |
What LADWP's leak-detection gauge can and cannot show
LADWP says movement on the meter's leak-detection gauge after all indoor and outdoor water use is off means there is a leak. The same guidance says that movement does not identify the exact source.
The gauge stops after every water use is fully off
Document when the original symptom appears; an intermittent fixture, drain, pool, or irrigation problem may need a timed check.
The gauge continues moving
Record the meter result and request leak detection. Do not choose an access point from the gauge alone.
The bill spike follows irrigation use
Check irrigation separately from the indoor plumbing because LADWP identifies irrigation leaks as one possible source.
An active leak requires water to be turned off
LADWP says customers can contact the utility by phone or in person for shutoff assistance needed for emergency repairs.
LADWP's meter guidance confirms unexplained flow, not the failed pipe. The private-property source and repair still need to be located and documented.
Sources: LADWP - How to Detect a Water Leak, LADWP - Water Billing Adjustment for Underground Leak Repair
Get help with a leak detection problem in Los Angeles
Describe the moisture, sound, meter reading, affected area, and whether water is actively spreading.
No-obligation request · Availability varies by location and provider
What professional leak detection service does
Hidden leaks can quietly cause damage and drive up your water bill long before you see them. Plumbing Advisors helps you spot the warning signs and connect with leak detection help.
Professional leak detection begins with the symptom history and accessible plumbing. The provider may compare meter behavior, isolate fixtures or lines, and use noninvasive tools before recommending access through a wall, floor, or ceiling.
No single observation or tool finds every leak. The useful result is a documented location and a clear explanation of what supports the proposed access and repair.
What may be behind unexplained water use or moisture
A worn fixture or connection
Toilets, faucets, supply connections, and appliance lines can lose water where the problem is still accessible.
Sources: EPA WaterSense - Home Maintenance
A hidden pressurized line
A supply-line leak may continue while fixtures are off and can show up as meter movement, sound, or spreading moisture away from the source.
Sources: EPA WaterSense - Leak Detection and Flow Monitoring Devices
Irrigation or water-using equipment
Outdoor irrigation and water-using equipment can create unexplained use that should be separated from the plumbing inside the home.
Sources: EPA WaterSense - Leak Detection and Flow Monitoring Devices
Aging, corrosion, pressure, or cold
EPA lists older piping, corrosion, irregular pressure, cold temperatures, equipment problems, and installation issues as possible causes. The visible symptom does not tell you which one applies.
Sources: EPA WaterSense - Leak Detection and Flow Monitoring Devices
What you can safely check first
- Look under sinks and around toilets, faucets, appliances, hose connections, and irrigation controls for visible water.
- With every indoor and outdoor water use stopped, note the meter reading and check it again after two hours without using water.
- Record when the stain, sound, odor, or dampness appears and whether it changes after a nearby fixture is used.
- Close a known fixture or main shutoff only when it is easy to reach and safe to operate.
- Do not cut into walls, floors, or ceilings to search for the source.
Treat the meter as a clue, not a location tool
A changed reading after two hours with no water use probably indicates a leak. It does not show where the water is escaping, and monitoring alerts still need investigation before access or repair is approved.
Sources: EPA WaterSense - Home Maintenance, EPA WaterSense - Leak Detection and Flow Monitoring Devices
When leak detection should not wait
For an active leak that requires utility shutoff help, LADWP directs customers to report it by phone or in person. After the flow is controlled, address wet materials promptly and arrange the private-property detection and repair.
- Water is actively spreading and the property shutoff is not safe or effective
- The meter gauge moves rapidly after all indoor and outdoor uses are off
- A wall, ceiling, or floor is becoming wetter
- Private-property water control is needed before emergency repair can begin
Sources: LADWP - Water Billing Adjustment for Underground Leak Repair, EPA - A Brief Guide to Mold, Moisture and Your Home
How the leak should be narrowed down
The test should answer the next unresolved question. A tool is useful only when the provider can explain what the result shows and how it affects the access plan.
| Method | Where it may fit | Important limitation |
|---|---|---|
| Visible fixture and connection check | Drips, puddles, damp cabinets, or water near an accessible fixture | It does not rule out a second hidden source. |
| Meter comparison and isolation | Unexplained water use when no fixture is intentionally running | It confirms a pattern but does not pinpoint the leak. |
| Moisture, flow, acoustic, or thermal testing | Water believed to be behind a finished surface or below a floor | Each tool has limits and should be interpreted with the plumbing layout. |
| Targeted access | A location supported by multiple observations or test results | The opening and restoration scope should be clear before work begins. |
Sources: EPA WaterSense - Home Maintenance, EPA WaterSense - Leak Detection and Flow Monitoring Devices
What genuinely changes the leak check in Los Angeles
Indoor and outdoor water use must both be off
LADWP's gauge check includes water use inside and outside the home. A pool component, irrigation zone, running toilet, or faucet can otherwise make the meter look like a hidden building leak.
Sources: LADWP - How to Detect a Water Leak
LADWP does not repair private-property leaks
LADWP states that private-property leaks are the owner's repair responsibility. Utility shutoff assistance and the private leak-detection and repair scopes are separate steps.
Sources: LADWP - Water Billing Adjustment for Underground Leak Repair
The proposed opening should follow the evidence
A meter result, moisture alert, or thermal pattern can narrow the search, but each has limits. Ask the provider to explain which observations support the exact wall, floor, ceiling, or exterior access point.
Sources: LADWP - How to Detect a Water Leak, EPA WaterSense - Leak Detection and Flow Monitoring Devices
Comparing a leak detection estimate
A useful estimate separates locating the leak from opening the surface, repairing the failed component, drying affected material, and restoring finishes. Ask what evidence must be found before each additional step is authorized.
Scope factors
- Whether the source is visible or hidden
- The number of lines or zones that need isolation
- The locating methods required
- Access through walls, ceilings, floors, or exterior areas
- Urgency and whether water is still active
- Repair, drying, and finish restoration after the source is found
Questions for the estimate
- Is the detection fee separate from the repair?
- Which test is included, and what can it confirm?
- What finding will justify opening a finished surface?
- Who is responsible for drying and restoring the opened area?
What to tell Plumbing Advisors
A short record of meter readings, timing, visible moisture, and recent water use gives the professional a better place to start.
- The exact meter readings and how long no water was used
- Where moisture, sound, odor, or staining appears and when it changes
- Which fixtures, appliances, irrigation zones, or hose connections were checked
- Whether water is active now and whether a known shutoff reduced it
- Whether pools, irrigation, and every indoor use were off during the LADWP meter check
- Who will document the location, access plan, repair scope, and restoration responsibility
Plumbing Advisors does not dispatch its own local technicians. The independent professional is responsible for confirming availability, credentials, diagnosis, price, warranty terms, and work performance.
Leak Detection in Los Angeles: frequently asked questions
What does a moving LADWP leak-detection gauge mean?
LADWP says movement after all indoor and outdoor water use is off means there is a leak. It also says the movement does not identify the exact source.
Should irrigation be checked before indoor leak detection?
Yes. LADWP identifies irrigation-system leaks as one possible reason for an unusual bill spike. Outdoor use should be fully off and checked separately from the home's interior plumbing.
Will LADWP repair a leak on my property?
No. LADWP says it does not repair private-property leaks. The owner must arrange detection and repair after the source is narrowed down.
Can LADWP help turn off water for an active leak?
LADWP says customers can contact the utility by phone or in person for help turning off water needed for emergency repairs. That assistance is separate from the private repair.
Sources and editorial methodology
Sources are included when they substantively support a local, safety, technical, or consumer decision on this page.
- LADWP guidance supports the meter-gauge procedure, fixture and irrigation checks, shutoff assistance, and private-property boundary.
- Meter movement is never presented as the location or cause of the leak.
- EPA guidance supports national monitoring limits and moisture response.
U.S. Environmental Protection Agency
EPA WaterSense - Home MaintenanceU.S. Environmental Protection Agency
EPA WaterSense - Leak Detection and Flow Monitoring DevicesU.S. Environmental Protection Agency
EPA - A Brief Guide to Mold, Moisture and Your HomeLos Angeles Department of Water and Power
LADWP - How to Detect a Water LeakLos Angeles Department of Water and Power
LADWP - Water Billing Adjustment for Underground Leak Repair
