Leak Detection Guides for Homeowners
Most leaks announce themselves before they become expensive. This section covers how to find hidden leaks, test your plumbing with just a water meter, identify slab leaks before they destroy your foundation, and make small pipe repairs yourself.
Five leak detection topics covered in depth
- Signs of a slab leak — the symptom checklist that identifies a slab leak before flooring and drywall get destroyed. What to do when you suspect one.
- Water meter leak test — a 30-minute DIY test that confirms whether you have an active leak anywhere in your plumbing system, with zero tools.
- Pipe repair clamp guide — the right temporary fix for a pinhole leak or cracked pipe while you plan a permanent repair. Types, installation, and limits.
- Under-sink leak repair — the most common household leak. Covers supply line, drain, P-trap, and garbage disposal connection failures with step-by-step fixes.
- Water pressure too high — high pressure damages pipes, appliances, and water heaters silently over years. How to test it and what to do about it.
Quick leak diagnosis guide
Visible drip from a fixture
Check whether the leak is from the supply side (water under pressure) or the drain side (water only when the fixture runs). Supply leaks: tighten compression fittings or replace supply lines. Drain leaks: usually a failed P-trap slip joint or deteriorated putty under the drain basket.
Water bill spiked unexpectedly
A silent running toilet can waste 200 gallons/day. Do the toilet dye test first (drop food coloring in the tank — if it appears in the bowl without flushing, the flapper is leaking). Then do the meter test to confirm no other leak is active.
Wet spot on floor, wall, or ceiling
Check whether the wet spot is below a bathroom, laundry room, or kitchen. Most ceiling leaks trace to the bathroom directly above — look for a wax ring failure or a leaking supply line first. Wet floors with no fixture above may indicate a slab leak.
Low water pressure throughout the house
A sudden drop in pressure across all fixtures (not just one) points to a supply-side leak, a partially closed main shutoff, or a failing pressure-reducing valve. Check the main shutoff first — it's often inadvertently bumped during other work. If the shutoff is fine, do the meter test to check for active leaks.
Leak repair cost reference (2026)
| Repair Type | DIY Cost | Pro Cost |
|---|---|---|
| Supply line replacement (under sink) | $10–20 | $75–150 |
| P-trap replacement | $10–25 | $100–200 |
| Pipe repair clamp (temporary) | $10–30 | N/A (DIY fix) |
| Pressure reducing valve replacement | $50–100 | $250–500 |
| Slab leak repair | Not DIY | $500–4,000+ |