How to Find a Hidden Water Leak in Your Home (and What to Do About It)
Identify and fix hidden water leaks with our comprehensive guide, including detection tips and repair costs.
Nov 2, 2026 · Efrain Realzola
Licensed & insured · Texas Responsible Master Plumber RMP44420 · TDLR AC Contractor TACLA22663C · Family-owned since 2018 · 2024 and 2026 Nextdoor Fave
How do you know if you have a hidden water leak?
The quickest check is your water meter. Use no water for two hours, then look again. If the numbers moved, water is going somewhere you can't see. The EPA says the average home loses nearly 10,000 gallons a year to leaks, and about one in ten homes loses 90 gallons or more every day.
Most hidden leaks give you a warning before they turn into a big repair. You just have to know what to look for. This guide walks you through the signs, a simple at-home test to confirm a leak, where leaks usually hide, what a plumber does to find them, and what it costs to fix one here around Lago Vista and Lake Travis.
If you're in a hurry: shut off your main water valve and call us at (512) 662-2949. We'd rather you call about a leak that turns out to be nothing than wait on one that's real.
Signs of a hidden leak
What you see
Damp, stained or bubbling drywall, flooring or baseboards
Cracks in tile or drywall, or doors that suddenly start to stick
A soggy or unusually green patch in the yard, especially in dry weather
Rust or drips under sinks and around the water heater
What you hear or feel
Running or hissing water when every fixture is off
A warm spot on the floor, which can mean a hot water line is leaking
Water pressure that used to be better
What you smell
A musty odor with no visible cause
Sewage near a wet patch outside, which may be a drain or grinder pump line leak rather than a water line
What shows up on paper
A water bill that goes up when nothing about how you use water has changed. If that's you, our guide to why your water bill is so high covers the other common causes too.
How to check for a hidden leak yourself
You don't need tools for this. A pen, some food coloring and about two hours is enough to tell whether you have a leak and roughly where to look.
Step 1: The water meter test
Turn off everything that uses water: faucets, the dishwasher, the washing machine, the ice maker, and any sprinklers.
Find your water meter. It's usually near the street under a concrete or plastic lid.
Write down the reading, or take a photo of it. Many meters also have a small leak indicator, a triangle, star or dial, that spins when even a trickle of water is moving.
Wait two hours without using any water.
Check again. If the reading changed or the indicator is moving, water is going somewhere.
This tells you a leak exists. It doesn't tell you where.
Step 2: Is it inside the house or in the yard?
Find the shutoff valve where the water line comes into your home. Look in the garage, at an exterior wall, or in a box near the foundation.
Close it, then watch the meter again.
If the meter keeps moving, the leak is in the line between the meter and the house. That's usually a buried line.
If the meter stops, the leak is somewhere inside the house.
If you can't find the shutoff valve, or it won't turn, that's worth knowing before an emergency. Call us and we'll help you sort it out.
Step 3: Check the toilets
Toilets are one of the most common sources of silent leaks.
Take the lid off the toilet tank and put a few drops of food coloring in the tank, not the bowl.
Wait 10 to 15 minutes without flushing.
If color shows up in the bowl, the flapper is leaking.
Flush right away so the dye doesn't stain the tank.
A leaking flapper is usually an easy fix. See our toilet repair page.
Step 4: Look at the usual suspects
Under every sink, for drips, damp cabinet floors or rust on the pipes
Around the base of the water heater, for puddles, rust or a damp floor
Behind the washing machine, for wet hoses or fittings
Outside, along the line from the meter to the house, for soggy or unusually green ground
Hose bibs and sprinkler valves, for slow drips
What if the meter moved and you can't find the leak?
That's the point where a plumber earns their trip charge. And please don't cut into drywall or a slab to look for it yourself. A hole in the wrong place can cost more than the leak.
Where hidden leaks usually are
Where you notice the clue often points to where the leak is.
Where
What you might notice
What it can mean
Under the slab
A warm spot on the floor, running water sound, a high bill, damp flooring
A leak in a line running under the foundation, often a hot water line
Inside a wall
A stain or bubbling paint that keeps coming back, a musty smell, a damp baseboard
A leaking pipe, fitting or valve behind the wall
In the ceiling
A brown ring or sagging spot, often under an upstairs bathroom or the attic
A leak from a supply line, drain or fixture above
Yard or buried line
A soggy or unusually green patch, a meter that keeps moving with the main valve closed, lower pressure
A leak in the water line between the meter and the house
At the water heater
Rust, a puddle, a damp floor, a tank that seems to run all the time
A leaking tank, fitting, valve or relief line. See water heater repair
Under a fixture
Damp cabinet floor, a musty smell, warped wood
A leaking supply line, drain or faucet. See faucet repair
A toilet
Color in the bowl after the dye test, a toilet that runs or refills on its own
A worn flapper or fill valve. See toilet repair
Why leaks happen around Lago Vista and Lake Travis
Leaks don't happen at random. A few things around here make them more likely.
Hard water and older pipes. Central Texas water is hard, and over the years minerals and corrosion wear out pipes, fittings and valves. Older homes are the most likely to develop pinhole leaks.
High water pressure. Pressure much above 80 psi stresses pipes, fittings and fixtures, and leaks often follow. A pressure-reducing valve protects your plumbing, and we install and repair them.
Shifting soil. Central Texas clay and limestone swell and dry out with the weather, and that can stress buried lines and the plumbing under a slab.
Freeze damage. A hard freeze can crack pipes and fittings, and the leak may not show up until the thaw or later. Our broken pipe repair page covers freeze and burst-pipe repairs.
Grinder pump systems. Many homes in Lago Vista and around Lake Travis use a grinder pump that pushes wastewater through a pressurized line. A wet patch of ground with a sewage smell may be a leak in that line, not a water line. We handle both. See our grinder pump service page.
Lake and weekend homes. A leak in a house that sits empty can run for days before anyone notices. Shutting off the main water valve when you leave is the cheapest protection there is.
How a plumber finds a hidden leak
The goal is to find the leak without opening up your walls and floors until we know where to cut. Here's how it goes on a leak detection call.
We start with what you've seen. What you've heard, smelled and noticed on your bill narrows down where to look.
We test and pinpoint. We use pressure testing, fixture isolation and non-invasive locating to narrow the leak down to a section of pipe.
We show you what we found. You get your options in plain words and a written price before any repair begins.
We tell you before we open anything. If a wall or floor has to be opened, we tell you where, why and what it costs first.
How leaks get repaired
Most repairs fix the leaking section, whether that's a fitting, a section of pipe or a fixture connection. If your pipes are failing in several places, we'll talk with you about whether repiping makes more sense than paying for repair after repair. And we'll tell you honestly if that's not the case. For pipes outside the house or leaks that need more than a spot fix, see broken pipe repair.
What leak repair costs
What you pay depends on where the leak is, how hard it is to reach, the pipe material and the size of the repair. A leak at a fixture or an exposed pipe is a very different job than one inside a wall or under a slab. Our starting prices once the leak is found:
Plumbing leak repair: starts at $389
Pipe repair: starts at $700
Frozen or burst pipe repair: starts at $800
Water line repair or replacement: starts at $2,800
Plumbing inspection: starts at $495
Every visit starts with a $65 trip charge, and we credit it toward the work when you go ahead. You get a written price before anything starts.
If you plan to file an insurance claim, tell us when you call and ask your insurance company what documentation it needs. We can give you the written price to share with them.
What to do right now if you think you have a leak
Shut off the main water valve if water is spraying, pooling or soaking something. If it's a slow leak and you're not sure, you can leave the water on while you do the meter test.
Take a photo of the meter reading and write down the time. It helps us, and it helps if you ever file an insurance claim or ask your utility about your bill.
Turn off the power to any wet area if water is near outlets, appliances or the electrical panel, and stay out of standing water.
Move anything valuable out of the wet area, and soak up standing water with towels.
Call us at (512) 662-2949. Tell us what you've seen, what the meter did, and whether the leak stops when the main valve is closed.
What not to do
Don't cut into drywall, flooring or a slab to go hunting for the leak.
Don't ignore a warm floor spot, a damp wall or a bill that keeps climbing. Leaks don't fix themselves.
Don't keep running the water just to see if the problem gets worse.
Don't pour chemicals into drains or pipes to "fix" a leak.
Don't wait to find out whether it's a big deal if you smell sewage near a wet spot in the yard.
When is a hidden leak an emergency?
Treat it as an emergency if water is spraying or flowing and you can't stop it, water is near your electrical panel or outlets, a ceiling is sagging or bulging, or you smell sewage. Shut off the main valve and call right away.
Our phones are answered Monday through Friday, 7:30 a.m. to 8 p.m., and Saturday, 8 a.m. to noon. We don't dispatch overnight. If a leak starts after hours, shut off the main valve, protect what you can, and call when we open.
How to prevent hidden leaks
You can't stop every leak, but a few habits catch most of them while they're small.
Know where your main water valve is. Everyone in the house should know, and it should turn easily. Exercise it once a year so it doesn't seize up.
Check your water pressure. Sustained pressure much above 80 psi wears on every pipe and fitting. If yours runs high, a pressure-reducing valve is cheap protection.
Read your meter once in a while. Take a quick look when nothing's running. It's the earliest warning you'll get.
Look at your water bill. A jump with no change in how you use water is a clue.
Fix drips and running toilets right away. A dripping faucet and a leaking flapper add up to thousands of gallons a year.
Check under sinks and around the water heater a few times a year. Look for damp spots, rust and corrosion on fittings.
Shut off the main valve when you leave a lake or weekend house for a few days. It's the cheapest protection there is.
Think about leak sensors near the water heater, under sinks and by the washer. They sound an alarm when they get wet.
Schedule a yearly check. Our plumbing maintenance visits catch worn valves, hoses and fittings before they leak.
If you'd like it handled for you, Real Home Care covers your plumbing, heating and cooling for $45 a month. Call (512) 662-2949.
When to call a plumber
Your meter moves when everything is off, and you can't find the cause
You hear running or hissing water with every fixture off
You have a warm spot on the floor, or damp, stained or bubbling walls, ceilings or floors
A wet or soggy patch shows up in the yard, or your pressure dropped
Your water bill jumped and the toilet dye test came back clean
You find a leak and can't stop it
Start with our leak detection page. We find the leak, explain what we found in plain words, and give you a written price before any repair starts.
Where we work
We're a family-owned shop with locations in Lago Vista (20811 Dawn Dr, Unit 706) and Lakeway (2802 Flintrock Trace). We serve homes in Lago Vista, Jonestown, The Hollows, Highland Lake Estates, Northshore on Lake Travis, Point Venture, Lakeway, Bee Cave, Horseshoe Bay, Marble Falls, Cedar Park, Leander, Crystal Falls Parkway, Anderson Mill, Round Rock and Austin.
Our hours are Monday to Friday, 7:30 a.m. to 8 p.m., and Saturday, 8 a.m. to noon. Call (512) 662-2949 or contact us. Learn more about our family-owned shop.
Frequently Asked Questions
How do I know if I have a hidden water leak?
Watch for a water bill that rises with no change in how you use water, the sound of running water when everything is off, a warm spot on the floor, damp or stained walls, a musty smell, or a soggy patch in the yard. Then do the meter test to confirm.
How do I check for a leak with my water meter?
Turn off everything that uses water, write down the meter reading, wait two hours without using any water, and check again. If the reading changed, water is going somewhere.
How can I tell whether the leak is inside the house or in the yard?
Close the shutoff valve where the water line enters your home. If the meter keeps moving, the leak is in the line between the meter and the house. If it stops, the leak is inside.
How do I check a toilet for a leak?
Put a few drops of food coloring in the tank, wait 10 to 15 minutes without flushing, and see whether color shows up in the bowl. If it does, the flapper is leaking. Flush right away so the dye doesn't stain the tank.
Can I find a hidden leak without tearing into my walls or floors?
Often, yes. We use pressure testing, fixture isolation and non-invasive locating first, so walls and floors stay closed until we know where to open them.
Is a hidden water leak an emergency?
It is if water is spraying or flowing and you can't stop it, water is near electrical outlets or your panel, a ceiling is sagging, or you smell sewage. Shut off the main valve and call. A slow leak is less urgent, but it never fixes itself.
What causes hidden leaks in Lago Vista and around Lake Travis?
Hard water and older pipes, high water pressure, shifting clay and limestone soil, freeze damage, and homes that sit empty for days. A wet patch outside with a sewage smell can also be a leak in a grinder pump line.
How much does leak repair cost?
Plumbing leak repair starts at $389, pipe repair at $700, frozen or burst pipe repair at $800, and water line repair or replacement at $2,800. The final price depends on where the leak is and how hard it is to reach. Every visit starts with a $65 trip charge that we credit toward the work, and you get a written price before anything starts.
How much water can a small leak waste?
A lot more than you'd think. The EPA says the average home loses nearly 10,000 gallons a year to leaks, and about one in ten homes loses 90 gallons or more a day.
Will insurance cover a hidden leak?
It depends on your policy and on what caused the leak. Ask your insurance company what documentation it needs, and tell us when you call. We can give you the written price to share with them.
Can a leak make my grinder pump alarm go off?
Yes. A running toilet or a leak that sends extra water into the tank can make the pump cycle all day and fall behind. See our grinder pump alarm repair page.
What should I do while I wait for the plumber?
Shut off the main water valve if you can't stop the leak, photograph the meter, move valuables out of the wet area, and soak up standing water. Stay out of standing water if it's near electrical outlets or your panel.