Why is my water bill suddenly so high with no visible leak?

Most unexplained high water bills with no visible interior leak are caused by hidden leaks in the underground water service line, a slab leak under the foundation, or an irrigation leak. These leaks run continuously and are invisible from inside the house, but they show up on the meter and on every bill until they're found and fixed. The fastest way to confirm a hidden leak is the meter test: 30 to 60 minutes with no water use, watching whether the leak indicator moves.

How can I tell if I have a hidden water leak?

The most reliable home test is the meter test: shut off every water source in the home, then check whether the leak indicator on your water meter still moves over 30 to 60 minutes. Any movement means water is escaping the system. Other warning signs include a warm spot on the floor (hot-water slab leak), unexplained wet patches in the yard (underground service line), the sound of running water with everything off (wall or slab leak), and bills that climb without any change in habits.

What is slab leak detection?

Slab leak detection is the process of pinpointing a leaking water pipe under a concrete foundation without breaking up the entire slab. Plumbers use acoustic listening equipment, electronic line tracing, pressure testing, and thermal imaging together to identify the exact spot of the leak before cutting concrete. With good detection, the repair excavation is typically a foot or two square, not the whole room.

How do plumbers find a leak in an underground water line?

Underground service-line leaks are usually located with acoustic equipment that listens for the sound of pressurized water escaping the pipe, combined with electronic line tracing to map the pipe's path. Pressure testing confirms whether the line is losing pressure, and the location is verified before any digging, so the repair excavation is small and targeted, not a full-yard dig.

How much water can a hidden leak waste?

According to EPA WaterSense, household leaks waste nearly 1 trillion gallons of water nationwide every year, and the average household's leaks can waste nearly 10,000 gallons a year. A single running toilet can waste 200 gallons or more a day, and a large hidden underground line leak can run well past the calculator's 7,000-gallon low-end estimate in a month, all of it billed at your tiered water rate.

Is leak detection worth it before tearing up the floor or yard?

Yes. Professional leak detection costs a fraction of the alternative: exploratory excavation, opening drywall, or breaking up flooring to find a leak by trial and error. Pinpointing first means the repair is small, targeted, and far less disruptive. It also tells you whether you have a single leak or a failing line that should be replaced rather than patched.

What causes slab leaks in Inland Empire homes?

The most common causes in the Inland Empire are corrosion of aging copper lines, soil movement that stresses pipes, abrasion where pipes contact concrete or rebar, and original construction defects in homes built between the 1960s and early 1990s. Hot-water-line slab leaks are especially common because heat accelerates pinhole corrosion.

What happens when Sweetwater comes out to find a leak?

A Sweetwater Plumbing technician comes to your home, performs a complete leak diagnosis and fixture inspection, and provides written options for any leaks identified. If we open drywall to reach a leak, we patch it, and on a slab leak we help you with the insurance paperwork.

How long does it take to find a hidden water leak?

Time depends on the home. Slab leaks and underground service-line leaks can take more work if the pipe path is complex or if multiple methods are needed to confirm the location. Sweetwater technicians combine acoustic, electronic, and pressure-testing methods to keep the process fast and the repair excavation small.

Do you provide leak detection in my city?

Yes. Sweetwater Plumbing provides leak detection services across the Inland Empire, including Montclair, Ontario, Upland, Rancho Cucamonga, Chino, Chino Hills, Claremont, Pomona, Fontana, Rialto, San Bernardino, Riverside, Corona, Norco, Eastvale, Mira Loma, Diamond Bar, La Verne, San Dimas, Colton, Grand Terrace, Highland, Loma Linda, and Redlands. Call (909) 312-4516 or text (909) 247-6791 to get started.

Hidden Water Leak Calculator | Sweetwater Plumbing

Step 1 of 3

Step 1

Tell us a little about your water usage. This sets your real rate, not a national average.

Pick whichever you have handy. The more accurate your input, the more accurate the cost estimate. We use Inland Empire tiered rates for water and sewer combined (about $0.007 to $0.011 per gallon, depending on your district and tier).

How do you want to start?

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I'll enter my water bill

Most accurate. Use a recent bill, combined water + sewer if listed.

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I don't have my bill handy

We'll estimate from household size and city.

Average bill amount *

Include water + sewer if billed together. Skip fixed service charges if listed separately.

Billing period

Your city We'll match your city to its actual water utility and use real local rate data. Inland Empire averages run $0.007 to $0.011 per gallon (water + sewer combined).

Step 2

Check anything you've noticed.

Check all that apply. We'll only use this to estimate ranges: your answers stay in your browser and aren't sent anywhere.

A toilet that runs continuously or won't stop refilling Biggest culprit

One of the most expensive household leaks. Often so quiet you only notice it when you're standing right next to the toilet.

A toilet that "ghost flushes," refilling on its own every so often Common

Usually a worn flapper. EPA estimates these waste ~200 gallons per day silently.

A faucet that drips even when turned all the way off Smaller

Each drip adds up: one drip per second can waste about 3,000 gallons a year, per EPA.

A faucet or showerhead with a constant trickle or fast drip Common

Worse than a slow drip, typically 10-20× the loss. Often a worn cartridge or valve seat.

A visible leak under a sink, behind a toilet, or at a fixture Fix soon

Even a slow drip in a cabinet causes hidden damage: mold, rot, swollen subfloor. That costs more than the leak itself.

The water meter dial moves when nothing is running Hidden leak

A classic sign of a slab leak, irrigation leak, or hidden line leak. Often the biggest single contributor to a high bill.

A warm spot on the floor, or the sound of running water with everything off Possible slab leak

Often a hot-water-line slab leak. It wastes water continuously and costs energy to heat the lost water. Often shows up first as an unexplained spike on the bill.

An irrigation zone with a broken head, popped pipe, or always-wet spot Often missed

Outdoor leaks are easy to overlook because the water disappears into the soil. Often the largest single waste in summer months.

My water bill went up significantly and I don't know why Worth investigating

A 20%+ jump with no change in habits usually means a leak somewhere. A technician can come out and find the source.

None of the above Nothing visible

If none of these sound familiar but your bill still seems high, the leak may be somewhere you can't see, like the underground line to your home.

Estimated hidden water cost

Hidden leaks could be costing you

$0 to $0

per year, from the issues you checked

This is an estimate based on EPA WaterSense fixture data and your district's rates. Actual amounts depend on severity, duration, and water/sewer pricing tiers. Only a visit from a technician can confirm.

Want to know for sure?

Call or text us. A Sweetwater Plumbing technician will come to your home, find the leak, and give you written repair options before any work starts.

☎ (909) 312-4516 💬 Text (909) 247-6791

How we calculated this

Fixture loss rates: Running toilet ≈ 6,000 gal/month silent and flapper leak ≈ 200 gal/day (EPA WaterSense); dripping faucet ≈ 3,000 gal/year per drip-per-second (EPA WaterSense); slab/hidden line leak ≈ 7,000+ gal/month uncorrected (Sweetwater estimate).

Water rate: Matched to your city's actual water utility from a built-in directory covering 24 Inland Empire cities. Rates are blended residential water + sewer cost per gallon, calibrated from each agency's published 2025-26 tier rates. Inland Empire averages run $0.007-$0.011 per gallon depending on whether you're served by a municipal utility, a special district, or an investor-owned company like Golden State Water.

Ranges: Low estimate assumes minor/early-stage leaks. High estimate assumes moderate severity, a full-year duration, and tiered-rate penalty pricing. Severe leaks can exceed the high end.

Sources: EPA WaterSense Fix a Leak Week, IEUA water-wise guidance, plus each utility's published rate schedule (linked above when you selected your city).

CSLB #889182 · Licensed C-36 Plumbing Contractor · Your answers stay in your browser. Nothing is saved or sent.

Hidden water leak detection for Inland Empire homes with a bill that won't behave.

Tell us a little about your water usage. This sets your real rate, not a national average.

Check anything you've noticed.

Where to look first.

Want to know for sure?

How we calculated this

How to find a hidden water leak before it drains your bank account.

How do I check my house for a hidden leak?

1. Shut off every water source in and around the home.

2. Find and read your water meter.

3. Wait 30 to 60 minutes without using any water.

4. Test each toilet individually.

5. Walk the exterior and check for wet spots.

6. Listen near walls and at fixtures.

What are the signs of a hidden water leak?

How do plumbers find a hidden water leak without tearing the house apart?

Acoustic leak detection

Electronic leak detection

Pressure testing

Thermal imaging

Video pipe inspection

Dye and tracer methods

Why hidden leaks are so common in Inland Empire homes.

Hard municipal water and aging copper

Shifting soil

Slab-on-grade construction (1960s-1990s)

Aging irrigation systems

Original galvanized lines

Hidden water leak detection FAQ.

Leak detection across the Inland Empire.

More on water leaks and detection.

Sources and further reading