Water Bill Suddenly High in California: Signs of a Hidden Leak

If you’ve recently looked at your water bill and were shocked to find a steep increase in your apparent water usage, this could be a warning sign. If you have experienced no change in your water use but still see a sharp uptick in your water bill, it is possible that the culprit is a hidden leak.

If your water bill increases by more than 20% in a single month without habit changes, you likely have a hidden leak.

Source: North Bay Homeowner Guidelines

A hidden leak isn’t just a water bill problem, it’s a foundation problem. Much of the North Bay, including neighborhoods in Novato and Petaluma, sits on expansive clay soil. This soil absorbs water and physically swells, exerting upward pressure on slabs and footings.

Many North Bay towns were built out decades ago, and the original galvanized steel and cast iron supply lines are reaching the end of their service life. Main line failures in these older systems tend to happen underground and out of sight, which is exactly why non-invasive leak detection services using acoustic sensors and thermal imaging rather than exploratory digging are so critical for preserving property value. You shouldn’t have to worry about Marin County high water bill disputes or growing foundation damage to your Sonoma County property.

Locations to Check Before Calling for Non-Invasive Leak Detection Services

If you suspect there may be a leak in your plumbing, a good first step is to go through and check all of your appliances to see if there is an obvious leak coming from any fixtures.

• Toilets – Flapper or fill valves that are broken or misaligned can allow water to continue to flow when they are supposed to seal. See if there is any water pooling around the bottom of the toilet. Poor food coloring in the tank and see if it spills into the bowl to check for a flapper leak.
• Water heater – Take a look at your water heater to make sure there are no signs of corrosion, loose fixtures, or water pooling around the tank.
• Faucets – Check sink and tub faucets as well as shower heads for any dripping. Even if it is a slow drip, the amount of water wasted can add up and lead to a large amount of wasted water.
• Slab – Underground pipes can corrode or bend, leading to leaks that seep into the home’s foundation. Check for warm, damp, or damaged spots in your flooring.
• Irrigation – Sprinkler systems can become damaged from tree roots and soil shifts. Look for any unexplained soggy and muddy spots in the yard.

Meter Test

Another way you can test for a hidden leak is through your water meter. If you find the water meter running when water is off, this is a clear sign of a problem.

1. Stop using all the water in your house. Make sure the washing machine, dishwasher, and all other appliances using water are not running. You can also shut off the main water valve.
2. Locate your water meter, which should be in the ground box near the street in front of your property. Remove the cover and find the meter.
3. If the flow indicator is moving, this means water is still flowing somewhere and there is probably a leak.
4. Take a picture of the reading and then wait for about an hour.
5. Come back and see if the reading has changed. If it has increased, water is leaking somewhere in your plumbing.

Residents in Santa Rosa, Petaluma, and San Rafael can log into their city’s smart meter portal, such as Santa Rosa’s WaterSmart platform, to pull continuous hourly consumption data. If you see usage registering between 2 AM and 4 AM, when every faucet and fixture in the house is off, that’s a strong signal of a pressurized leak running somewhere in your system.

The “dead hours” test is straightforward in practice. Usage during those overnight hours can’t be explained by dishwashers, irrigation schedules, or household activity, which makes any spike unmistakably suspicious.

Slab Leaks and the ‘Warm Spot’ Phenomenon in Eichler Homes

Eichler homes can present a unique problem because of their radiant heat systems: a system of underground pipes used to circulate warm water to create heat. Eichler homes are uniquely vulnerable to slab leaks: leaks in the water pipes located within the concrete slab foundation of a home. Slab leaks occur because their radiant heat systems run copper piping directly through the concrete foundation. And when those lines fail, the signs show up underfoot before anywhere else.

A localized warm patch on your tile or linoleum floor is one of the classic Eichler radiant heat leak signs, a hot water line leak beneath the slab. Many Eichler owners dismiss the sensation for months, assuming the system is simply cycling when this happens. By the time they investigate, saturation of the foundation soil is already underway and water usage is skyrocketing, leading to Marin County high water bill disputes.

⚠️ Eichler Owner Warning: Because radiant piping is embedded in the slab itself, even a slow leak creates direct, continuous contact between escaping water and your foundation. This dramatically accelerates soil saturation compared to a standard above-slab plumbing failure.

What to Do if There’s a Leak

If you have confirmed or if you suspect there is a leak in your house or are noticing things like Eichler radiant heat leak signs, it is best to call a plumber right away. Leak detection plumbers have professional equipment that can locate hidden plumbing leaks without causing damage to your home.

John Owens Services is an experienced plumber who provides leak detection services to homeowners in the Sonoma and Marin County areas. We provide slab leak detection in Petaluma clay soils, radiant leaks in Eichler homes, and more. We can locate any hidden water leak and immediately provide a repair so that the leak doesn’t grow worse, cause damage to your house, and continue to increase your water bill.

We use modern non-invasive methods in order to locate hidden leaks without senselessly tearing apart your home. Thermal imaging for leak detection is a trustworthy method. Thermal imaging: locates temperature differentials through flooring and walls without a single cut, pinpointing exactly where moisture is accumulating beneath the surface. We also use acoustic sensors: detectors that pick up the distinct frequency signature of pressurized water escaping a pipe, narrowing the search area to inches, not feet. These technologies mean technicians arrive with answers, not just access points.

When You DON’T Need Leak Detection: When to Call a Plumber Instead

Though there are many cases of hidden leaks secretly charging your water bill and leading to damage to your house, there are plumbing leaks that occur where calling for plumbing service is the better option rather than paying for a technician to locate a leak that’s already visible. Though you may find the water meter running when water is off, you could still be able to locate the source of the issue yourself.

• Leaks that are clearly coming from a fixture. If water is pooling around the toilet or water heater, it is clear the leak is coming from there. Same with any faucet that is continuously dripping. Seeing these visual indicators means it is time to call a plumber to repair the leak.
• Toilet flappers. A way to test a hidden leak within a toilet is to pour a couple drops of food coloring into the tank. If the color then begins seeping into the bowl without flushing, this means the flapper is leaking and you can contact a plumbing professional to repair it.
• Visible water dripping. If you see clear water damage in an area of the ceiling in your house or water dripping down, it is clear you have a plumbing leak, likely from a shower or bathtub upstairs. Rather than hire someone to locate it, it would be better to have a plumber address it right away.

Protecting Your Property with a Professional Approach

Local expertise is the difference between a targeted repair and a costly guess. Contractors who understand Marin and Sonoma County’s building codes, radiant slab systems, and hillside foundation dynamics can diagnose problems accurately the first time, without tearing into finished walls or concrete floors unnecessarily. We are knowledgeable in methods such as thermal imaging for leak detection that can accurately identify a leak without having to do any risky guesswork.

John Owens Services has been a licensed plumber in Sonoma and Marin County since 1986. We are experts in the area and know how to go about treating local properties for leaks so that foundations aren’t ruined. We specialize in both leak detection and plumbing repair, so you can call us if you are unsure of where the leak is coming from in your home, or if you already know what the problem is and you need us to fix it.

If you’ve noticed rising water bills, warm spots on your floor, or unexplained moisture in your home, don’t wait for the damage to continue. John Owens Services Inc. provides non-invasive leak detection for Marin and Sonoma that locates pipe leaks under slabs, underground, and inside walls without unnecessary demolition.

Key Takeaways

• Check locations such as the toilet, water heater, faucets, floors, and yard to see if you can pinpoint the location of a leak.
• Use the water meter to determine if there is a silent leak, either by turning the water off and checking the meter or monitoring water usage during “dead” hours.
• Remember that Eichler homes are prone to slab leaks and can show themselves through warm patches on the floor.
• Don’t call for leak detection when you can clearly see evidence of a plumbing leak. Call a plumber to repair the issue.
• Call for professional non-invasive leak detection services when you are seeing signs of a leak but no visible water leaks.