An underground water leak is one of the most frustrating problems a BC property owner can face. The water is invisible, the source is hidden metres below ground, and every day it runs it costs money and may be damaging your foundation, landscaping or driveway. Yet with modern detection technology, finding the exact leak position — without digging up your whole yard — is entirely achievable.
This guide covers everything you need to know about underground leak detection in BC: the signs to look for, the methods technicians use, and what to expect from a professional inspection.
Signs You Have an Underground Leak
Underground leaks often start small and grow over months or years. Watch for:
- A water meter that spins with everything off — the most reliable early warning sign
- Unexplained wet or unusually green patches in a lawn or garden with no recent watering
- Water appearing on the surface from pavement, a driveway or a sidewalk
- Persistent pressure loss in the building
- Rising water bills with no change in usage
- Settling or cracking in a driveway, walkway or patio over a buried line
- Sinkholes or depressions forming along a pipe route
The water meter test is simple: close every fixture and valve inside the building and watch the meter dial for 10–15 minutes. If it moves, water is leaving the supply system somewhere.
Why Underground Leaks Are Serious
Beyond wasting water and inflating bills, underground leaks cause:
- Foundation damage — saturated soil near a foundation eventually undermines it, leading to cracking and settlement
- Sub-base erosion — the flow of water beneath a driveway or slab washes away the supporting material, creating voids
- Landscape and hardscape damage — trees, gardens and paving are damaged by both the water and the repair excavation when the leak goes undetected too long
- Mould risk — leaks that saturate the soil against a foundation wall eventually introduce moisture into the basement
The Detection Methods We Use
Acoustic Listening and Correlation
Acoustic leak detection uses ground microphones placed on the surface to detect the sound of water escaping a pressurised pipe. Electronic filtering isolates the leak frequency from traffic and other noise. A correlator — the most precise acoustic tool — places sensors at two points on the pipe and calculates the exact leak position from the time difference in the sound's arrival at each sensor.
This is the standard method for metal supply lines (copper, galvanised, cast iron, ductile iron) under pressure.
Tracer Gas
For plastic, PEX or HDPE lines that make little acoustic noise, we introduce a safe tracer gas (5% hydrogen / 95% nitrogen) into the isolated, drained pipe. The gas escapes only at the leak and rises through the soil, where a sensitive probe at the surface detects it. Tracer gas works on any non-metallic buried line, including irrigation systems and radiant heating.
Ground-Penetrating Radar (GPR)
GPR maps the pipe's route, depth and the soil around it. It also reveals voids and saturated zones caused by the leak — information that tells us how long the leak has been running and how far the damage has spread. GPR is especially valuable before excavation to confirm the pipe position and avoid other buried utilities.
Pipe and Cable Locating
Electromagnetic pipe locating traces conductive lines from a known access point — meter pit, valve or fitting — and marks the route along the surface. This is the starting point for any underground investigation: we need to know where the pipe runs before we can efficiently survey it for leaks.
What to Expect from a Professional Underground Leak Investigation
- Initial confirmation — we perform a pressure test or meter observation to confirm there is a leak and quantify the loss rate
- Pipe route mapping — EM locating or GPR traces the route so acoustic sensors are placed in the right locations
- Leak location — acoustic correlation, ground microphone or tracer gas identifies the position
- Surface marking — we mark the surface directly above the leak with a depth estimate
- Written report — documenting the method, location, evidence and excavation guidance for your plumber or civil contractor
A professional investigation typically completes in 2–4 hours for a standard property. Larger sites or complex pipe networks may take longer.
Serving All of British Columbia
LeakInspections.ca is a division of Anyleak.ca, BC's longest-serving leak detection company. We serve Metro Vancouver, the Fraser Valley, Vancouver Island, the Okanagan and all of BC. Call 604-239-9934 to discuss your underground leak and schedule an inspection.