Portland Slab Leak Experts
Portland’s post-WWII slab-on-grade homes in Beaverton, Tigard, and Milwaukie are hitting the age window where copper supply lines under the slab develop pinhole leaks. Here’s everything you need to know.
+1 (971) 293-4200 Call Now — We Answer 24/7These indicators mean a supply line under your slab may be losing water.
A hot water line leaking under the slab heats the concrete above it, producing a warm or hot spot on tile or hardwood floor that doesn’t change with heating system use.
With every fixture off, the sound of running water audible through the slab or at floor level indicates pressurized water escaping below the concrete.
A slab leak runs continuously at full supply pressure. Monthly water bills that climb steadily without any visible source are a classic slab leak indicator.
Moisture wicking up through the slab to the subfloor and wall base produces mold at floor level without any visible moisture source above — a late-stage sign.
Beaverton, Tigard, Milwaukie, and the outer neighborhoods of Portland developed rapidly in the 1950s and 1960s with slab-on-grade construction — a building method that pours the concrete foundation directly on prepared soil, without a basement or crawl space. In these homes, supply lines — copper in this era — run through the concrete slab itself or immediately beneath it to supply bathrooms and kitchens above.
Copper supply lines under slabs last 50–70 years under normal conditions. Portland’s post-WWII construction is now 60–75 years old. The pitting corrosion that produces pinhole leaks in copper pipes occurs from the outside of the pipe inward when the surrounding concrete or soil has sufficient moisture and electrochemical activity — conditions that exist under Portland’s concrete slabs. The result: the copper pipe develops pinhole leaks that are initially too small to produce surface symptoms, running water into the subgrade silently while the meter climbs.
Before any professional service, run the water meter isolation test: close the interior main shutoff, check the meter. If the meter continues showing flow with the shutoff closed, the leak is between the meter and the interior shutoff — likely the underground supply line. If the meter stops when the interior shutoff closes, the loss is inside the home.
With the interior shutoff open and everything in the house off, a still-moving meter with no visible source confirms active loss somewhere in the supply system. If you feel a warm spot on the floor or hear water below the slab with everything off, the slab is the primary suspect.
Professional slab leak detection uses amplified acoustic equipment to hear water escaping through a pipe wall under pressure. The sound of pressurized water exiting a pinhole produces a specific frequency signature — different from background noise and from the sound of water flowing normally through a pipe. A trained technician moves the sensor across the floor surface, listening for the point of maximum signal intensity.
On concrete slab surfaces, acoustic detection can narrow a leak location to within 6–12 inches before any concrete is broken. This precision means the access hole is targeted, not exploratory. Compare this to the alternative: guessing the location and breaking open a 4-foot section of floor looking for the failure point.
We also use pressure isolation testing to confirm which supply branch is losing water (hot vs. cold, which zone of the house) before starting acoustic detection — this narrows the search area from the full slab footprint to a specific supply run. Thermal imaging supplements acoustic detection for hot water line leaks, which produce a temperature signature on the floor surface above the failure point.
A simple meter test before calling confirms active water loss and helps us advise on the likely scale before we arrive. Turn everything off, check the flow indicator, take two readings 30 minutes apart. The loss rate (gallons per hour) tells us how large the failure is likely to be and helps prioritize urgency.
After detection and location, you have three repair paths. We present all three with costs so you can make the decision that fits your situation:
Direct slab access repair — Targeted jackhammer opening over the detected leak location, pipe repair or section replacement, slab patch with concrete. This is the least disruptive when the failure is isolated and the surrounding copper is in good condition. Typical cost in Portland: $1,500–2,800 depending on slab depth, floor finish above (tile vs. hardwood vs. carpet), and repair scope.
Above-slab reroute — A new supply line is run through walls and ceiling to bypass the failed slab section entirely. No concrete breaking. The failed slab pipe is abandoned in place. This is preferred when the floor above the leak is expensive hardwood or tile you don’t want to disturb. Cost depends on routing distance: typically $1,200–2,500. Longer reroutes through multiple walls or ceilings add labor.
Whole-house repipe — If the slab copper is at end of life throughout — multiple pinholes or a very old system with systemic pitting — repiping with PEX bypasses the entire slab supply system permanently. Cost in Portland for a typical 1,200–1,800 sq ft slab home: $8,000–12,000 including PEX supply lines, access work, and restoration. This eliminates the problem permanently and typically produces a rebate on homeowner’s insurance for the improved system.
All three options are available through our Portland leak detection service — we detect, present options with real numbers, and let you decide.
Think you have a slab leak? We locate it acoustically before any concrete is broken, then present your repair options with honest costs.
Call +1 (971) 293-4200Portland homeowners in post-WWII slab homes ask these about slab leak detection.
Acoustic detection locates it before any concrete breaks. Three repair options with real costs.
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