Why Your Lawn Has Dry Spots (Sprinkler Coverage Fixes)

You water faithfully, yet certain patches of lawn stay brown and crispy. Persistent dry spots almost always point to an irrigation coverage problem — not a watering-amount problem. Here's how to diagnose and fix uneven sprinkler coverage.

Why dry spots happen

• Poor head-to-head coverage: sprinklers should be spaced so each one's spray reaches the next. Gaps leave dry zones.
• Clogged or worn nozzles: reduced output in one spot.
• Blocked spray: plants, furniture, or tall grass interrupting the pattern.
• Mismatched heads: mixing spray and rotor heads on one zone waters unevenly.
• Low pressure: heads that don't throw far enough to overlap.

Run a coverage test

Place a few cups around the lawn and run the zone for a set time, then compare how much water collected in each. Big differences reveal where coverage is weak. This 'catch-cup' test quickly pinpoints uneven areas.

Fix the coverage

Depending on the cause: clean or replace clogged nozzles, adjust spray patterns and radius, raise heads buried by grass, add or relocate a head to close a gap, or correct mismatched heads so the zone is uniform. Make sure each head's spray reaches its neighbors (head-to-head coverage).

Rule out pressure issues

If heads mist or barely spray across the whole zone, the problem may be water pressure or a line leak rather than coverage. Our irrigation specialists can evaluate pressure and design even coverage.

Frequently asked questions

Why is part of my lawn always dry?

Almost always a coverage gap, a clogged head, or blocked spray in that spot — not insufficient watering time.

What is head-to-head coverage?

Spacing sprinklers so each head's spray reaches the adjacent heads, ensuring overlapping, even coverage with no dry gaps.

Arbol Roble has cared for Inland Empire landscapes since 1997, serving Rancho Cucamonga, Ontario, Fontana, Eastvale, Corona and Riverside. Request a free quote or browse our residential and commercial services.