Field notes
Part of my lawn is brown but the sprinklers run. Why?
Usually a clogged or tilted head, a zone with low pressure from a leak, or heads never spaced to reach that spot. A zone-by-zone check finds it in under an hour.
If one area browns while the rest of the lawn is fine, the water is usually not reaching it. The common causes, roughly in order:
- A head that sank, tilted, or got clogged. Mowers, foot traffic, and settling clay knock heads out of line.
- Low pressure in the zone. A broken line or a leaking valve drops pressure, so heads at the end of the run barely pop up.
- Mismatched nozzles. A replacement nozzle with a different spray rate leaves dry gaps between heads.
- Heads that never reached the spot. Some systems were never laid out for full coverage.
Running more water rarely fixes it and can cause fungus in the wet areas. A zone-by-zone check finds the cause, and most head and nozzle fixes are done the same visit. If the brown area is a ring with a yellow-orange edge in spring or fall, it may be large patch instead, a lawn disease (see our note on brown patch).