Leak Detection
& Repair
A hidden water leak costs money every hour it runs — and causes damage that compounds silently inside walls, under floors, and beneath slabs. Bison Plumbing locates the exact leak position using acoustic listening, thermal imaging, and pressure testing before opening a single surface. Then repairs it precisely. Warren, MI since 1998.
Leak detection locates hidden water leaks in supply lines, joints, and under-slab pipes using acoustic listening devices, thermal imaging cameras, and pressure testing — before any wall, floor, or slab is opened. Once the exact leak location is confirmed, targeted repair minimizes the opening required. Detection: $150–$400. Supply line repair: $200–$800. Slab leak repair: $500–$3,000. Part of Bison’s Plumbing Repairs services. Pre-1970 homes with corroding galvanized steel supply lines are the dominant leak scenario in Metro Detroit.
How to Tell If You Have a Hidden Leak — The Water Meter Test
- Turn off every fixture, appliance, and water-using device in the house — including the ice maker, irrigation system, and washing machine.
- Locate your water meter — typically in the basement near the foundation wall or in a pit near the sidewalk. Note the current reading or watch the low-flow indicator (a small triangle or dial).
- Wait 15 minutes without using any water.
- Check the meter again. If the reading has changed or the low-flow indicator is still moving, water is flowing somewhere in your system with nothing running — you have a hidden leak.
- Call Bison for a professional detection evaluation. The meter test confirms a leak exists; acoustic and thermal detection confirms exactly where it is.
Three Types of Water Leaks in Metro Detroit Homes
Supply Line Pinhole Leak
Corrosion in aging galvanized steel or copper supply lines creates tiny holes in the pipe wall. Water escapes under pressure and follows the path of least resistance — soaking insulation, wicking into framing, and creating hidden mold conditions before any visible sign appears at the surface.
- Unexplained water bill spike — $30–$100+ per month
- Stained or bubbling drywall near supply lines
- Mold odor in walls without visible moisture source
- Soft or discolored flooring above or below a supply line run
Joint Seepage
Solder joint failures in copper plumbing — particularly in homes with older lead-based solder — develop slow seepage at the joint connection rather than a sudden pinhole. Threaded galvanized connections corrode at the threads over time, producing a similar slow seep that may drip for months before it becomes visible.
- Mineral deposit “ring” visible around a pipe fitting
- Slow persistent drip from a joint — not under active flow
- Water meter moving very slowly with all fixtures off
- Corrosion “blush” or green staining at copper joints
Slab Leak
In Metro Detroit’s slab-on-grade homes, copper supply lines installed beneath the concrete in the 1950s–1970s develop pinhole corrosion leaks under the slab. Water migrates upward through concrete, appearing as warm or wet spots on floors. Without precise acoustic and thermal detection, locating this type of leak requires guesswork — and guesswork means jackhammering the wrong section of your floor.
- Warm or hot spots on concrete or tile floors
- Sound of running water in the floor when nothing is on
- Significant unexplained water bill increase — constant loss
- Cracks in slab or foundation walls near wet areas
All photography on this page is Bison Plumbing’s own work in Macomb and Oakland County homes.
Three Non-Invasive Detection Methods
The key discipline in leak detection is confirming the exact leak location before any surface — wall, ceiling, or floor — is opened. Each detection method addresses different leak scenarios:
Acoustic Listening Devices
Specialized ground microphones and acoustic amplifiers detect the sound of water escaping under pressure — including through concrete slabs and behind finished walls. The technician moves the sensor in a grid pattern above the suspected area, listening for the characteristic hiss or rushing sound of a pressurized leak. Acoustic detection can locate a slab leak to within 3–6 inches from above the concrete, avoiding unnecessary jackhammering.
Thermal Imaging
Infrared thermal cameras detect temperature differentials on surfaces — a slab leak from a hot water line shows as a warm anomaly on the floor surface; a cold water leak shows as a cool area in a warm wall cavity. Thermal imaging is most effective when the leaking pipe carries water at a different temperature than its surroundings, making it particularly powerful for locating hot water supply line leaks beneath slabs and inside walls without disturbing any surface.
Pressure Testing
The supply system is isolated into sections and pressurized. Pressure drop in a specific isolated section confirms a leak within that segment — narrowing the search area from the full system to a specific zone before acoustic or thermal detection pinpoints the exact location. Pressure testing is also used after repair to confirm the leak has been fully resolved before closing any opened surfaces.
Why Metro Detroit Homes Have More Hidden Leaks
Pre-1970 Supply Lines — The Dominant Leak Risk in Macomb and Oakland County
The housing stock in Warren, Ferndale, Royal Oak, and Birmingham was built primarily between 1940 and 1970 — a construction era when galvanized steel supply lines were standard in residential plumbing. Those pipes are now 50–80 years old. Galvanized steel corrodes from the inside out: the zinc coating that resists rust dissolves over decades, exposing the bare steel beneath to the water it carries. The result is progressive interior scaling that reduces flow, joint deterioration that produces seepage, and ultimately pinhole failures that can occur anywhere along the supply run.
Hard water chemistry in Macomb and Oakland County accelerates this process. Calcium and magnesium minerals in the water supply deposit scale inside pipe walls — adding internal corrosion pressure that compounds the existing galvanized deterioration. A home built in 1955 in Royal Oak with its original supply lines has 70 years of hard water scale and galvanized corrosion working against it simultaneously.
Galvanized Steel
Corrodes from inside out. Scale buildup, joint seepage, and pinhole failures are expected in any intact run older than 50 years. Replacement is typically the most cost-effective solution when corrosion is widespread.
Early Copper
Lead-based solder at joints deteriorates over time. Pinhole corrosion from aggressive water chemistry. Under-slab copper from this era is the primary source of slab leaks in Metro Detroit.
Modern Copper & PEX
Significantly more resistant to corrosion. Lower leak risk but not immune — physical damage, improper installation, and freeze events can still produce failures requiring detection and repair.
Bison’s Leak Detection & Repair Process
Symptom Assessment — Narrow the Search Area
The technician reviews all symptoms with the homeowner — water bill history, meter test results, location of wet spots or sounds, and any recent plumbing work. This assessment focuses the detection equipment on the most likely search area before any instruments are deployed, saving time and improving accuracy.
Pressure Testing — Confirm Leak and Isolate Zone
The supply system is sectioned and each zone pressure-tested. A zone that fails to hold pressure confirms the leak is within that section — eliminating large portions of the supply run from the acoustic and thermal search. This reduces the detection area and speeds the pinpoint phase.
Acoustic and Thermal Detection — Pinpoint the Leak
Acoustic listening devices and thermal imaging are deployed over the confirmed leak zone. The technician works methodically — acoustic grid scanning for pressurized leak sound, thermal imaging for temperature differential on surfaces. Combined, these methods locate the leak to within a few inches. The exact location is marked on the surface above it — floor, wall, or ceiling.
Targeted Surface Opening — Minimum Required Access
With the leak location confirmed, the minimum surface opening is made — one small access panel in a wall, one core drill in a slab, or one targeted floor cut. The leak is exposed at the confirmed location. The surrounding area confirms the leak is where detection indicated — if not, the detection process repeats before expanding the opening.
Repair — Spot Fix or Section Replacement
Isolated pinhole or joint failure: spot repair at the confirmed location. If inspection of the exposed pipe reveals widespread corrosion suggesting imminent additional failures nearby, section replacement of the corroded run is presented as the more cost-effective long-term option. For homes with pervasive galvanized deterioration, full supply line replacement may be the right conversation.
Pressure Test — Confirm Repair Before Closing
After repair, the system is re-pressurized and tested before any surface is closed. Passing the post-repair pressure test confirms the leak has been fully resolved — not just addressed at one point while another failure continues nearby. The surface is closed only after confirmation.
| Service | Cost Range | Notes |
|---|---|---|
| Non-Invasive Leak Detection | $150–$400 | Acoustic listening, thermal imaging, and pressure testing. Written location report. Applied toward repair cost if Bison performs the work. |
| Supply Line Pinhole Repair | $200–$800 | Spot repair at confirmed leak location. Includes targeted surface access and pressure test confirmation after repair. |
| Joint Seepage Repair | $150–$500 | Re-solder or fitting replacement at the confirmed seepage joint. Post-repair pressure test included. |
| Slab Leak Detection & Repair | $500–$3,000 | Acoustic and thermal slab leak location + targeted core drill at confirmed location + pipe repair. Concrete patching additional. |
| Galvanized Supply Line Replacement | $800–$4,000 | Full or partial galvanized steel supply line replacement with copper or PEX. Scope determined by extent of corrosion confirmed during repair access. |
A pinhole supply line leak running at 1/2 gallon per minute wastes 720 gallons per day — roughly $3–$5 per day in water cost, plus accelerating water damage to framing, insulation, and drywall that compounds daily. Mold can establish within 24–48 hours in a wet wall cavity. A $200 detection visit that leads to a $400 repair is far less expensive than a $400 detection visit that leads to a $4,000 water damage remediation after the leak has been running undetected for 6 months.
For Warren, Ferndale, Royal Oak, and Birmingham homeowners with original 1940s–1960s plumbing that has never been assessed, a proactive supply line inspection — before a leak develops — can identify sections of galvanized steel showing advanced corrosion. Replacing those sections before they fail costs $800–$2,000. Waiting for the failure and then addressing water damage, mold remediation, and emergency repair can cost $8,000–$20,000. Contact Bison to schedule a supply line assessment.
Related Services
Plumbing Repairs Hub
All residential plumbing repair services — water heaters, backflow testing, sump pumps, and more.
Water Heater Repair
Water heater leaks are a common supply line issue — tank seepage, inlet/outlet connection failures, and pressure relief valve leaks.
Sewer Camera Diagnostic
When wet basement areas could be a sewer lateral leak rather than a supply line leak — camera inspection confirms the source.
Frequently Asked Questions — Leak Detection & Repair
The most reliable indicators are: an unexplained spike in your water bill; your water meter moving when all fixtures and appliances are off (the meter test); warm or wet spots on floors — particularly in slab-on-grade homes; mold odor or visible mold near plumbing without a visible source; sound of running water inside walls when nothing is on; and staining or bubbling paint or drywall. Any combination of these signs warrants a professional leak detection evaluation — the longer a hidden leak runs, the greater the water damage, mold risk, and structural impact.
A slab leak is a leak in a supply line running beneath a concrete slab foundation. In Metro Detroit’s pre-1970 housing stock, copper supply lines installed under slabs have been in ground for 50–70 years and develop pinhole corrosion. Detection uses acoustic listening devices — amplifying the sound of water escaping under pressure from above the slab — and thermal imaging cameras that detect temperature differentials on the floor surface caused by leaking water beneath. Once the location is confirmed to within a few inches, a targeted core drill at that point minimizes concrete removal for the repair.
Pre-1970 homes throughout Warren, Ferndale, Royal Oak, and Birmingham were built with galvanized steel supply lines that corrode from the inside out over decades. Michigan’s hard water mineral content accelerates this corrosion. Early copper plumbing from the same era used lead-based solder at joints that also deteriorates over time. A home more than 50 years old in Macomb or Oakland County that has never had supply line work is a statistically high risk for active or developing leaks.
Non-invasive leak detection with acoustic and thermal methods runs $150–$400. The detection fee is applied toward repair cost when Bison performs the repair. Supply line pinhole repair runs $200–$800. Slab leak detection and targeted repair runs $500–$3,000. Full galvanized supply line replacement runs $800–$4,000 depending on scope.
In most cases yes — but only when the leak is precisely located first. Non-invasive acoustic and thermal detection pinpoints the leak to within a few inches before any surface is opened. This means one small access panel in a wall or a single core drill in a slab — not opening walls across an entire floor or jackhammering large concrete sections. Bison locates precisely before recommending any surface opening. The cost of proper detection always saves more than it costs in reduced demolition and restoration work.
Suspect a Hidden Leak? Find It Before It Finds You.
Bison Plumbing locates supply line, joint, and slab leaks using acoustic detection, thermal imaging, and pressure testing — before opening any surface. Targeted repair. LARA-licensed. Warren, MI since 1998.
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