Start With the Water Meter Test
Locate your water meter, confirm every fixture and appliance in the house is off, including ice makers and irrigation timers, and note the reading. Wait 30 minutes without using any water and check again. If the number hasn't moved at all, your bill increase is almost certainly usage-related, not a leak. If it has moved, water is being lost somewhere in the system.
Rule Out the Most Common (and Cheapest) Cause First
A running or slowly leaking toilet is, by a wide margin, the most common source of an unexplained water bill spike, and it's also the least expensive to fix. A simple test: add a few drops of food coloring to the tank and wait 15 minutes without flushing. If color appears in the bowl, the flapper or fill valve is leaking, even if you can't hear it running.
What Points Specifically to a Slab Leak
If the meter test confirms water loss and you've ruled out every toilet in the house, the next signs to check are a warm spot on the floor (suggesting a hot water line leak under the slab), a faint hissing sound in a quiet room, or visible dampness at a slab edge with no other explanation. Any of these, combined with a positive meter test, is worth a professional leak detection visit.
Seasonal Usage Isn't Always the Villain, But Sometimes It Is
If your bill jumped right after you started running an irrigation system for the season, or after houseguests stayed for a week, that's worth ruling out before assuming a leak. Comparing this month's bill to the same month last year, rather than to last month, gives a more accurate sense of whether the increase is seasonal or unusual.
What to Do While You Wait for a Leak Detection Appointment
If your meter test came back positive and you've ruled out every toilet, it's reasonable to want to do something before a technician arrives. Shutting off the main water valve when you're not actively using water, particularly overnight, limits how much additional water is lost while you wait, without leaving the household without water entirely.
Take a photo of your water meter reading with a timestamp, and note the exact time you shut off and turned water back on. This gives a technician a useful data point for estimating how much water is being lost per hour, which can help prioritize how urgently the leak needs to be addressed.
Avoid the temptation to start investigating with a shovel or by opening drywall on a guess. Acoustic and thermal detection equipment finds the leak's actual location far more precisely than trial-and-error digging, and exploratory demolition based on a guess sometimes damages an area nowhere near the actual leak.
Tracking Your Water Bill Going Forward
Many Colorado water utilities, including systems serving Golden-area homes, offer online account access showing daily or even hourly usage rather than just the monthly total on your bill. Checking this periodically, especially after any plumbing work, gives you a much earlier warning than waiting for the next paper bill to arrive weeks later.
If your utility offers usage alerts for unusual spikes, turning that feature on costs nothing and catches a new leak within days rather than a full billing cycle, which can meaningfully reduce both the water waste and the eventual repair scope if a leak does develop again in the future.
High Water Bill Diagnostic Checklist
- Run the 30-minute water meter test with everything off
- Test every toilet in the house with the food coloring method
- Check for a warm spot on the floor or a hissing sound
- Compare this month's bill to the same month last year, not last month
- Check irrigation timer settings if you have a sprinkler system
- Enable usage alerts through your water utility's online account if available
Frequently Asked Questions
Even a small, continuous leak can add up to hundreds of gallons over a billing cycle, which is often enough to be clearly visible on a water bill even before it's visible anywhere in the home.
If you're not confident in the result, a professional leak detection visit with acoustic equipment gives a far more definitive answer than repeating the meter test.
Yes, especially early on; a slab leak can run for weeks with only a subtle bill increase before a warm spot or sound becomes noticeable, which is why the meter test matters even without other symptoms.
Some Golden-area utilities do flag unusually high consumption and may reach out, but this isn't guaranteed or immediate, so running your own meter test periodically is a more reliable way to catch a problem early rather than waiting for the utility to notice first.
It varies by leak size and flooring type, but weeks to a few months of an undetected slab leak can begin affecting flooring and, in more advanced cases, subfloor material, which is another reason to act on a positive meter test promptly rather than monitoring it for an extended period.
Related Services & Areas
This sometimes overlaps with Leak Detection, so it's worth checking if the symptoms match. For a closer look at the related repair, see our Slab Leak Detection & Repair page. Homeowners in Littleton, CO deal with this same pattern regularly, given the similar soil and climate factors across this part of Jefferson County.
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