Leak Detection & Slab Leak Repair in Altadena, CA

Found an active leak? Our emergency plumbers can be on-site fast. If leaks keep recurring in an aging system, a whole-house repipe may cost less long-term than repeated repairs.

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The Signs You’re Dealing With a Hidden Leak

Hidden leaks announce themselves indirectly. Watch for: a water bill that jumps 30%+ with no usage change (the single most reliable indicator — check your meter); the sound of running water with all fixtures off; warm or damp spots on floors; new cracks in tile or lifting flooring; musty smells in a specific area; a water heater that runs constantly; or lush, soggy patches in the yard over the supply line’s path.

Before calling, do the meter test: turn off everything in the house, note the meter reading, wait 30–60 minutes without using water, and read it again. If it moved, water is escaping somewhere — and you have a confirmed leak, not a high bill from a running toilet (check toilets first with food coloring in the tank; a silent flapper leak wastes hundreds of gallons a day and mimics a hidden leak).

How Pros Actually Find Leaks (No Guesswork, No Random Digging)

Professional leak detection is a diagnostic discipline with real instruments. Here’s the toolkit and what each one does:

• Acoustic listening: ultra-sensitive ground microphones and headphones that amplify the hiss of pressurized water escaping a pipe. The tech maps the loudest point — often within inches — through slab or soil. This is the primary tool for slab leaks.
• Thermal imaging: infrared cameras that reveal temperature anomalies — a hot-water slab leak shows as a warm plume spreading through the concrete. Fast, non-invasive, and excellent for narrowing the search area.
• Pressure testing and isolation: the system is pressurized and isolated section by section. If the hot side holds pressure but the cold side drops, the leak is on the cold side — halving the search area before any instrument comes out.
• Moisture meters and borescopes: pin-type meters confirm dampness inside walls; tiny cameras inspect inside wall cavities through a half-inch hole instead of opening the whole wall.
• Tracer gas: for stubborn cases, the line is filled with a harmless hydrogen-nitrogen mix and a sniffer detects where it surfaces — accurate to inches even under deep slab.

Slab Leaks: Spot Repair, Reroute, or Repipe?

Altadena has plenty of mid-century slab-on-grade homes, and slab leaks — pressurized supply lines failing under the concrete — are their signature nightmare. Once the leak is pinpointed, three fixes exist, and the right one depends on the pipe’s overall condition:

Spot repair ($800–$2,500): jackhammer a small opening at the marked location, cut out the failed section, and repair it. Makes sense when the pipe is otherwise healthy (copper in good shape, first leak, isolated cause like a kink or abrasion). The downside: you’re opening slab, and if the system is aging, the next leak is a matter of time.

Reroute ($1,500–$4,000): abandon the under-slab line entirely and run a new PEX or copper line overhead through walls and attic to the affected fixtures. No slab demolition, and the new line is accessible for the future. This is the sweet spot for a single failed under-slab run in an otherwise okay system — increasingly the default recommendation.

Full repipe ($5,000–$15,000+): when detection finds (or history shows) multiple leaks, or the under-slab system is galvanized or aging copper with systemic corrosion. If you’re jackhammering the slab twice, you’ve spent reroute money and still own failing pipe. See our whole-house repipe framework for the full decision logic.

The decision rule: first slab leak in a healthy copper system → spot repair or reroute. Second leak, or any leak in galvanized → reroute at minimum, and price the full repipe. Never spot-repair the same failing system twice.

Pinhole Leaks in Walls: The Altadena Special

In foothill homes with original copper or galvanized supply lines, pinhole leaks inside walls are the most common hidden leak we see. A pinhole starts as a weep — barely enough to notice — and soaks insulation, drywall, and framing for weeks. By the time the stain appears on the ceiling below, the damage is extensive.

Detection here combines moisture-meter mapping (tracing the damp gradient uphill to the source) with targeted borescope inspection — a half-inch hole instead of a demolished wall. The repair itself is usually straightforward: open a surgical section of drywall, replace the failed pipe section, and — critically — assess the rest of the run. One pinhole in galvanized means the system is talking to you; listen the first time. If the failed section is part of a corroded galvanized run, the honest recommendation is repiping that run, not patching it.

What Leak Detection and Repair Costs (2026)

Detection: $250–$500 for a full instrument survey with a marked location — money well spent, since it converts a jackhammer-everywhere job into a surgical one. Spot repairs: $800–$2,500 depending on access (under-slab costs more than in-wall). Reroutes: $1,500–$4,000 depending on distance and fixture count. Full repipes: $5,000–$15,000+.

What drives price up: slab access (concrete cutting, dust control), leaks under finished flooring that must be matched afterward, and multiple leaks found during the survey. What drives it down: accurate detection (every hour of searching you avoid is money saved), accessible attic or crawlspace routing for reroutes, and catching it early — a $300 detection visit beats a $5,000 mold remediation every time.

Leak Detection & Slab Leak FAQs

Your Water Utility Already Told You: Read the Alert

More leak-detection calls start with a letter or alert from the water company than with any visible symptom. If your utility contacts you about unusual usage, or your bill jumps suddenly — we have seen customers go from $80 to $500+ in a single cycle — treat it as a confirmed lead, not a billing error. Smart meters flag continuous flow patterns that match hidden leaks with remarkable accuracy. Do not wait for a second high bill to “make sure.” Every week of delay is water and money disappearing into the ground, and in slab-on-grade homes, prolonged leaks erode soil under the foundation.

Can I Just Get the Leak Located and Fix It Myself?

Yes — detection-only service is a real option, and we are upfront about it. Some homeowners want a professional pinpoint (within inches, marked on the floor or wall) and then handle the repair themselves or hand it to their own contractor. You pay for the diagnostic visit, get a written location report, and that is it. What we will not do is pretend a vague “somewhere in this area” is good enough to dig on. If you are opening concrete or walls based on our mark, it needs to be right.

📞 Call (888) 555-0199