Your water bill just came in and it's $50, $100, maybe $200 more than usual. You haven't changed your habits, you didn't fill a pool, and you can't figure out where the water went. An unexplained spike in your water bill almost always means water is going somewhere you don't intend. Here are the seven most common causes — and how to track down the culprit.
1. Running Toilet
A running toilet is the single most common cause of high water bills. A toilet with a bad flapper valve can waste 200 gallons per day — that's 6,000 gallons per month. At Central Texas water rates, that adds $30–$80 to your monthly bill depending on your utility provider.
The tricky part is that a running toilet isn't always obvious. A slow leak from the tank to the bowl (sometimes called a "phantom flush") is silent. You won't hear it running, but your meter keeps spinning.
How to check: Put a few drops of food coloring in each toilet tank. Wait 15 minutes without flushing. If color appears in the bowl, that toilet is leaking. A new flapper costs $5–$10 and takes 15 minutes to install. See our full guide on running toilets for step-by-step instructions.
2. Hidden Plumbing Leak
A leak in a supply line inside a wall, under the slab, or in the main line between the meter and your house can waste enormous amounts of water without any visible signs — at least initially. A 1/8-inch crack in a pipe can leak 250 gallons per day.
Signs of a hidden leak: Damp or discolored spots on walls, ceilings, or floors. A musty smell in certain areas. Warped or buckled flooring. Warm spots on the floor (hot water slab leak). Sound of running water when everything is off.
How to check: Do the meter test (see below). If the meter confirms a leak but you can't find the source, you need professional leak detection.
3. Outdoor Irrigation Leak or Overuse
If you have a sprinkler system, it's one of the first things to check. A broken sprinkler head, a cracked line, or a stuck zone valve can dump hundreds of gallons per cycle. Some homeowners also don't realize how much water their irrigation system actually uses — a typical residential system uses 1,000–2,000 gallons per watering cycle.
How to check: Walk your property while the sprinkler system is running and look for geysers, pooling water, or unusually wet areas. Check your irrigation controller — did someone change the schedule? Is it running during rain? If you have a rain sensor, make sure it's working. In Central Texas, most lawns need 1 inch of water per week during summer — not every day.
4. Leaking Outdoor Faucets or Hose Bibs
A slow drip from an outdoor faucet is easy to overlook because you don't see it or hear it from inside the house. A faucet dripping once per second wastes about 5 gallons per day — or 150 gallons per month. A faster drip or a hose bib that doesn't fully shut off wastes much more.
How to check: Walk around your house and check every outdoor faucet. Turn each one on and off and look for drips from the handle, spout, or where the faucet meets the wall. Also check for wet spots around the foundation near any outdoor faucets.
5. Water Softener or Treatment System Malfunction
If your home has a water softener — common in Central Texas because of our hard water — a malfunction can cause it to regenerate too frequently. Each regeneration cycle uses 25–65 gallons of water. A softener that regenerates daily instead of every few days adds significant water usage.
How to check: Check the softener's display or timer for the regeneration schedule. Listen for the softener running at odd times. If you suspect a problem, bypass the softener temporarily and monitor your water usage for a few days.
6. Faulty Water Meter
Rare, but it happens. If your water meter is malfunctioning, it may record more usage than actually occurred. This is more likely with older mechanical meters.
How to check: Shut off every water-using fixture and appliance in your home (including ice makers, irrigation timers, and water softeners). Go to your meter and check whether the flow indicator is moving. If everything is off and the meter is still registering flow, either you have a leak between the meter and the house, or the meter is faulty. Contact your water utility to request a meter test — most will do this for free.
7. Seasonal Changes You Forgot About
Sometimes the spike isn't from a leak — it's from legitimate usage you didn't account for. Filling or topping off a pool uses 10,000–20,000 gallons. A new family member or extended house guest increases daily water usage by 50–80 gallons per person per day. Washing machines, especially older models, use 30–45 gallons per load. Watering new sod or landscaping can use hundreds of gallons per day.
How to check: Think about what changed in the billing period. Review your water bill history — some utilities provide monthly usage graphs that make spikes easy to spot.
The Meter Test: Your Best Diagnostic Tool
Here's how to determine definitively whether you have a leak. Step 1: Turn off every water-using fixture and appliance in the house. Everything — faucets, toilets, dishwasher, washing machine, ice maker, irrigation, water softener. Step 2: Go to your water meter (usually near the street, under a small cover in the ground). Note the reading or look for the low-flow indicator (a small triangle or star that spins when water flows). Step 3: If the indicator is spinning with everything shut off, you have a leak somewhere between the meter and your fixtures. Step 4: Wait 2 hours without using any water, then check the meter reading again. If the number changed, it confirms a continuous leak.
What to Do Next
If the meter test confirms a leak, your next step is professional leak detection. At Kimco, we use acoustic listening devices, thermal imaging, and electronic line tracing to find hidden leaks without tearing up your home. Once we locate the leak, we'll give you a flat-rate repair quote.
If the meter test comes back clean, the culprit is likely irrigation overuse, a malfunctioning softener, or simply higher-than-usual consumption. Review your habits and systems before assuming the worst.
Questions about your water bill? Call Kimco at (737) 260-7255. We provide leak detection and plumbing repair across Central Texas — from Caldwell and Cameron to Bastrop and Manor. Flat-rate pricing on every service.