Warm Spot on the Floor? Signs of a Hot Water Slab Leak in Arlington

If one patch of tile or wood floor feels warm under bare feet, a hot water pipe may be leaking under your concrete slab. The leak heats the slab from below, so the warm spot sits right above or near the pipe. A water heater that runs when no one is using hot water is the second big clue. If you notice either, call (817) 285-5426 for slab leak detection.

A warm floor is the classic sign, and slab leak detection in Arlington uses thermal cameras to trace it to one spot.

Why do hot water lines leak under the slab?

Hot water pipes expand each time hot water runs and shrink as they cool. Where a copper line touches concrete, gravel or another pipe, that motion rubs a thin spot over the years. Heat also speeds up wear from minerals. Arlington's clay soil adds stress as it swells and shrinks. In time a pinhole opens and water seeps into the soil under the house.

Most Arlington homes built from the 1960s to the early 2000s have copper water lines in or under the slab. Read more on why copper wears out in our guide to pinhole leaks in copper pipes, and how dry summers add stress in drought and slab leaks.

What are the signs of a hot water slab leak?

The five main signs are a warm or hot spot on the floor, a water heater that runs or refills far more than normal, the sound of running water with every tap closed, a higher gas or electric bill, and a higher water bill. Damp carpet, cracked tile or a musty smell near the warm area may show up later.

• A warm strip of floor that pets like to lie on
• The water heater burner or elements turning on when no one used hot water
• A faint hiss or rushing sound in a quiet house
• Gas or electric bills that climbed without a reason
• Hot water that takes longer than it used to reach the tap

Cold water lines leak under slabs too, and they do not warm the floor. See the full list in our slab leak signs guide.

How can I test for a hot water leak myself?

Close every tap, then close the cold water inlet valve on top of your water heater. Watch the water meter for 15 minutes. If the meter stops, the leak is likely on the hot side. If the meter keeps moving, the leak is on the cold side or somewhere else. Open the valve again when you finish.

1. Stop all water use. No dishwasher, washer, ice maker or sprinklers.
2. Check the meter. Note the small leak dial or the last digits. Our high water bill guide shows how to read it.
3. Close the heater inlet. It is the cold line on top of the tank.
4. Watch for 15 minutes. A stopped meter points to the hot side.
5. Feel the floor. After the heater runs, walk the floors in socks to find warm areas.

This test tells you which side is leaking, not where. Heat spreads in concrete, so do not cut the floor based on a warm spot alone.

Is a hot water slab leak an emergency?

It is urgent, but usually not a flood. You can stop the leak for now by closing the cold inlet valve on the water heater. Set a gas heater to pilot or vacation, or turn off the breaker for an electric heater, so it does not heat an empty tank. Water coming up through the floor or a fast-moving meter needs a call the same day.

If you need to stop all water to the house, our guide to the main water shut-off valve shows where it is in most Arlington homes.

How is a hot water slab leak found and fixed?

A technician isolates the hot line and runs a pressure test to confirm the leak. A thermal camera traces the warm path of the pipe, and acoustic gear listens for the hiss to pinpoint the spot. The fix is either a spot repair through a small opening in the slab or a reroute that runs a new hot line through the attic or walls.

Thermal imaging works very well on hot water leaks because the leak warms the floor. Learn more in how leak detection works. If your home has had more than one slab leak, a reroute is often the better long-term choice. Compare the options in our slab leak repair guide.

How much does slab leak detection cost in Arlington?

Slab leak detection in Arlington usually costs about $250 to $600. A basic leak check runs $150 to $400. You get the price before any work starts.

General estimates for Arlington, TX in 2026. Your exact price is confirmed before any work begins.