Wet Spot in Your Yard: Drainage Problem or Underground Leak?

A soggy patch in the yard presents a genuine diagnostic puzzle: is water coming up from a leaking pipe, or running off from somewhere it shouldn't pool? The two problems look similar, cost very different amounts to fix, and belong to different trades — so getting the diagnosis right before anyone digs matters enormously. Fortunately, one simple observation separates them in most cases.

The timing test: rain vs. dry weather

This is the key discriminator. Drainage problems appear after rain — water pooling where grading, gutters, or soil direct it — and dry out between storms. Pressurized pipe leaks run constantly, so the wet spot persists or grows during dry weather. A spot that's soggy in a Camarillo August, when it hasn't rained in months, is almost certainly a leak, not drainage. Keep a simple log for a week: wet or dry, and whether it rained.

Secondary clues

Leak-fed spots are often accompanied by a strip of unusually green, fast-growing grass — the lawn is being fertilized and watered from below. The soil may feel spongy or even vibrate faintly underfoot near a significant break. Drainage-fed spots tend to sit at low points, near downspouts, or along slopes, and the grass there is just wet, not supernaturally vigorous.

Confirm with the meter

If the timing suggests a leak, the water meter test settles it: shut off everything including irrigation and watch the flow indicator. Movement means a pressurized leak. Then close the house main valve — if the meter keeps moving, the leak is in the underground service line between the meter and the house.

What professional detection does next

An underground investigation is a two-step process: first electronically trace and mark the buried line's route, then use acoustic listening along that route to pinpoint the break. Pressure testing can confirm which segment leaks before any locating begins. The result is a marked dig spot — one hole, not a trench across the yard.

Frequently asked questions