If your water bill spiked and nothing about your household changed, the water is going somewhere you can't see. A hidden leak can waste hundreds of gallons a day silently — often before a single wet spot ever shows up. Here is how to confirm it, narrow down where it is, and know when it is time to bring in leak detection.
See Our Leak Detection Service →The Meter Test: Confirm a Leak in 15 Minutes
This one test separates a genuine leak from a simple billing surprise. If the meter holds steady, the cause may be a rate change or a one-time usage spike instead.
- ▸Turn off every water fixture and appliance in the home.
- ▸Find your water meter (usually near the street in a covered box) and note the reading, including the small leak-indicator dial or triangle if it has one.
- ▸Wait 15–20 minutes without using any water.
- ▸Check the meter again. If the numbers moved or the leak indicator is spinning, water is flowing somewhere — you have a leak.
The Most Common Hidden Culprits
| Leak source | Typical daily waste | How obvious is it? |
|---|---|---|
| Running toilet flapper | Up to 200 gallons | Often silent; may hear faint hissing. |
| Slab leak (under the foundation) | 50–250+ gallons | Hidden; warm floor spots, low pressure. |
| Irrigation / outdoor line | Highly variable | Hidden underground; greener patch of lawn. |
| Dripping fixtures & supply lines | 5–20 gallons | Sometimes visible under sinks. |
| Water heater relief valve | 5–30 gallons | Drip near the unit or drain pan. |
Signs the Leak Is Inside Your Walls or Slab
A running toilet is easy to catch and fix. The expensive ones hide. In San Jacinto's older and slab-foundation homes, a pinhole leak in a pipe beneath the concrete can run for weeks. Watch for a warm spot on the floor, the faint sound of running water when everything is off, unexplained low water pressure, or a musty smell near baseboards. Any of these alongside a high bill points toward a concealed leak that needs professional detection.
Know the Warning Signs of a Slab Leak →Why You Should Not Wait
Beyond the wasted water, a hidden leak does damage that compounds. Constant moisture rots subflooring, feeds mold, and undermines a foundation. What starts as an extra $40 on the bill can become a structural repair if it runs long enough. Professional leak detection uses acoustic and thermal equipment to pinpoint the source without tearing open walls or floors on a guess — so the repair stays as small and targeted as possible.
See How Leak Detection Works →If the meter test confirmed water is moving with everything off, don't keep paying for it. We'll locate the leak precisely and give you a clear repair plan.
Schedule Leak Detection →Frequently Asked Questions
How can I tell if my high water bill is from a leak?
Run the meter test: shut off all water, note the meter, wait 15–20 minutes, and check it again. If the reading moved, water is flowing somewhere — you have a leak.
What is the most common cause of a high water bill?
A running or leaking toilet is the single most common culprit and can waste up to 200 gallons a day silently. Slab leaks and outdoor irrigation leaks are the most common hidden causes.
Can a hidden leak really waste that much water?
Yes. Even a slow slab leak can waste 50 gallons or more per day, and a stuck toilet flapper can waste far more. Over a full billing cycle that adds up quickly.
How do you find a leak without tearing up my home?
We use acoustic listening equipment and thermal imaging to pinpoint the leak location precisely, so any access we need to open is small and targeted rather than exploratory.
Do you offer same-day leak detection in San Jacinto?
Yes, we offer same-day scheduling for leak detection across San Jacinto, Hemet, and the surrounding Riverside County area whenever availability allows.