GPR Scanning in Pukekohe

Pukekohe sits on the volcanic soils that made it one of New Zealand's best-known market gardening districts. That free-draining loam is kind to growers, but it also lets water from a broken pipe disappear straight down without surfacing, so leaks here often run for months before anyone notices a rising bill.

The town has grown well beyond its market-garden roots, with established streets, newer subdivisions on the fringes and a busy commercial centre. Reticulated water comes through Watercare, while many surrounding rural properties still run on bores, tanks and long private pipe runs that nobody has ever mapped.

Pukekohe is a short drive from our Waiau Pa yard, so it is an easy call-out for everything from pre-dig locates on new builds to tracing old galvanised lines under packhouses, yards and commercial premises along the main streets.

Around the town centre and the railway the houses are old enough to still run galvanised steel laterals, and in Pukekohe's dry, free-draining loam those pipes rust through from the outside as well as the inside. A pinhole on a galvanised line here almost never shows at the surface, because the water goes straight down toward the basalt. The streets from the 1960s and 70s are where we meet asbestos-cement mains and copper laterals; the AC cracks at its joints and under the weight of a widened driveway or a new vehicle crossing.

Houses from the late 1980s and 90s can have Dux Quest polybutylene inside and alkathene or early PVC outside, and it is the fittings, not the pipe, that let go. Everything built under the structure plan is MDPE with tracer wire. The market gardens around the town are different again: growers draw from the shallow basalt aquifer and the deeper Kaawa aquifer, and the bore lines and irrigation mains have gone in over decades without tracer wire, so an electromagnetic locator reads nothing until a digger finds the pipe the hard way. That is why we bring GPR and the hydro-vac to most Pukekohe jobs.