Slab Leak Detection & Repair — Waldorf, MD
A Waldorf homeowner had a water bill that had doubled over two months with no visible leak. We used pressure testing and acoustic detection to locate a pinhole leak in a copper supply line under the slab, made a targeted repair through a 12-inch core, and restored the floor.
The Problem
A homeowner in Waldorf called us after receiving two consecutive water bills that were double their normal amount. They had checked every visible fixture and found no dripping faucets, running toilets, or visible leaks anywhere in the house. Their water meter was spinning slowly even when all fixtures were off — confirming that water was flowing somewhere in the system. A neighbor had mentioned the possibility of a slab leak, and the homeowner called us because they had read that we perform slab leak detection.
Our Diagnosis
We confirmed the leak by shutting off all fixtures and watching the meter — it continued to spin at a rate consistent with approximately 0.5 GPM of flow. We isolated the hot and cold supply lines separately by closing the water heater supply valve: the meter stopped spinning when the cold line was isolated, confirming the leak was in the cold water supply. We then used acoustic detection equipment to listen for the characteristic hissing sound of pressurized water escaping through a small hole in the pipe. The signal was strongest in the master bathroom — approximately 8 feet from the exterior wall, under the slab. We marked the location and confirmed with a second acoustic reading.
The Repair Process
- 1Confirmed active leak: meter spinning with all fixtures off — approximately 0.5 GPM flow
- 2Isolated hot vs. cold supply: leak confirmed in cold water supply line
- 3Acoustic detection: located leak signal in master bathroom, 8 ft from exterior wall
- 4Confirmed location with second acoustic reading — 6-inch confidence radius
- 5Core drilled 12-inch access hole through slab at leak location
- 6Exposed copper supply line — found 1/8-inch pinhole leak at a fitting joint
- 7Cut out 18-inch section of copper pipe including the failed fitting
- 8Replaced with PEX-A using expansion fittings — no solder joints in the slab
- 9Pressure tested repair: 80 PSI for 2 hours — no pressure loss
- 10Patched core hole with hydraulic cement and concrete — floor restored
The Outcome
The water meter stopped spinning immediately after the repair. The homeowner's next water bill returned to normal. The repair was made through a single 12-inch core hole — no jackhammering, no trench, no major floor disruption. The PEX-A replacement section has no solder joints, which eliminates the failure mode that caused the original leak. The homeowner was relieved that the repair was far less invasive than they had feared.
Key Takeaway
A water bill that doubles with no visible leak is the most common sign of a slab leak. Acoustic detection allows us to locate the leak precisely before opening the slab — minimizing the access hole to 12 inches rather than a full trench. PEX-A replacement in the slab eliminates solder joints, which are the most common failure point.
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What Southern Maryland Homeowners Are Saying
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George Baker III
Annapolis, MD
May 2026
"We recently had Deep Dive Plumbing Maryland out to our home in Annapolis after we suddenly started noticing sewer flies throughout the house. They truly lived up to their name and performed a full "deep dive" diagnostic inspection instead of just treating the symptom. During their inspection they discovered our sewer pipe connected to the toilet had been leaking into the basement for quite some time. The team explained everything clearly, provided upfront pricing before starting any work, and even gave us a military discount which was greatly appreciated. They were professional, respectful, extremely knowledgeable, and took the time to make sure the repair was done correctly."
Angelis Reilly
Southern Maryland
June 2026
"TJ was great!! He answered our emergency call late evening hours. He was honest and gave us options to make a decision. Highly recommend!!"
Sally Ludwig
Dunkirk, MD
June 2026
"Great service with knowledgeable and neat professionals. Highly recommend! Deep Dive Plumbing helped with my bathroom project, including reinstalling a pedestal sink after new flooring was installed and addressing a toilet issue that had been causing constant clogs. The team was professional, courteous, and took the time to make sure everything was completed correctly. Their attention to detail and cleanliness really stood out. I am very happy with the results and would not hesitate to call them again."
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