Leak Detection and Repair in Fontana, CA: How to Find a Hidden Water Leak Before It Gets Worse

Water leaks are sneaky. The ones you can see — a dripping faucet, a puddle under the sink — are the easy ones. The leaks that cause the most damage are the ones you don’t notice until your water bill spikes, a wall starts discoloring, or you hear water running when everything is turned off.

A O Dowd Plumbing provides leak detection and repair throughout Fontana, Rialto, Rancho Cucamonga, Colton, and the Inland Empire. Here’s how to spot the signs of a hidden leak, what professional detection involves, and what to do if you find one.

Signs You May Have a Hidden Water Leak

• Your water bill has increased significantly without a change in usage habits
• You hear the sound of running water when no faucets or appliances are on
• Walls, ceilings, or floors have unexplained wet spots, staining, or bubbling paint
• Mold or mildew smell in a room that doesn’t have obvious moisture sources
• Your water meter is moving when all water sources in the house are turned off
• Warm or damp spots on the floor — a possible sign of a slab leak
• Low water pressure throughout the house without an obvious cause

Any one of these warrants investigation. Multiple signs together mean you should act quickly — water damage that’s been ongoing for weeks is far more expensive to remediate than damage caught early.

How to Check Your Water Meter for a Leak

This is the simplest at-home test for a hidden leak, and it takes less than two minutes.

First, turn off all water inside and outside the house — faucets, appliances, irrigation. Go to your water meter (usually near the street at the curb box) and check the leak indicator, which is typically a small triangle or dial that rotates when water flows through the meter. If it’s moving with everything turned off, you have a leak somewhere in your system.

For a slower check: read the meter, wait 30 minutes without using any water, and read it again. Any change confirms a leak. This test doesn’t tell you where the leak is — just that one exists. That’s where professional leak detection comes in.

What Professional Leak Detection Involves

Modern leak detection doesn’t require tearing open walls on a hunch. We use a combination of methods to pinpoint the leak’s location before any cutting or digging begins.

Acoustic Listening Equipment

Picks up the sound of water escaping under pressure through pipes, even when they’re buried in concrete or hidden behind drywall. Experienced plumbers know what a leak sounds like versus normal pipe noise.

Infrared Thermal Imaging

Reveals temperature differences in walls and floors caused by water — useful for detecting leaks in supply lines without any demolition.

Pressure Testing

Isolates sections of the plumbing system to determine which part is losing pressure. For slab leaks specifically, precise location is critical — every foot of wrong-direction digging is additional concrete repair cost.

Common Sources of Hidden Leaks in Inland Empire Homes

In our service area, the most common hidden leaks we find fall into a few categories.

Slab leaks are particularly common in older Fontana homes. The combination of hard water, reactive soil, and aging copper pipes creates conditions where pinhole leaks develop in pipes running under the slab. A slab leak can run for months undetected while slowly saturating the foundation.

Refrigerator and dishwasher supply lines fail quietly. The small braided hoses connecting these appliances to the water supply are often installed and forgotten. Rubber supply lines crack and leak at the connection point — we recommend upgrading to stainless steel braided lines.

Toilet wax ring failures cause water to leak slowly around the base of the toilet with each flush. The water wicks under the floor, and by the time you see damage, the subfloor has often been wet for a long time.

Outdoor irrigation system leaks can run underground for months without any obvious surface sign — the main clue is an unusually high water bill during months when irrigation is active.

Repair Options: Targeted Repair vs. Rerouting

Once we locate the leak, the repair approach depends on what caused it and where it is.

For an accessible pipe with an isolated leak, direct repair is usually straightforward — cut out the damaged section and replace it.

For slab leaks, there are three common approaches: direct access repair (breaking through the concrete above the leak, fixing the pipe, and patching), pipe rerouting (running a new line through the walls and attic to bypass the leaking section entirely), or epoxy pipe lining for certain leak types.

We’ll present the options and explain the trade-offs for your specific situation. For multiple pinhole leaks or badly corroded pipes, rerouting or repiping the affected section often makes more long-term sense than repeatedly repairing the same failing pipe.

Leak Detection and Repair in Fontana, Rialto, Rancho Cucamonga, and Beyond

Don’t let a hidden leak turn into a major water damage problem. Call A O Dowd Plumbing at (909) 684-1915 or request service online. We serve Fontana, Rialto, Rancho Cucamonga, Colton, Ontario, Highland, Chino, and surrounding Inland Empire cities. Same-day service is available.