A lawn can develop dry spots even when the sprinkler system runs on schedule. The important question is whether the dry area is actually receiving enough water—not simply whether the zone is turning on.
Start with the shape of the dry area
The pattern can reveal a lot. A narrow strip may point to a misaligned spray head. A wedge-shaped dry area can indicate a missing portion of a rotor arc. A large area near the end of a zone can suggest low pressure.
Watch the zone in daylight
Run the system manually when you can see the spray. Check whether neighboring sprinklers overlap, whether tall grass or shrubs block water, and whether a nozzle is clogged or a head is sitting too low.
Pressure can create coverage gaps
Low pressure shortens spray distance. If heads that used to overlap no longer reach one another, look for an underground leak, a partially opening valve or a change in zone demand.
Soil and exposure also matter
Sunny slopes, compacted soil and areas near pavement can dry faster than shaded lawn. Before adding runtime to the entire zone, confirm the problem is actually irrigation coverage.
Avoid watering the good areas more
If only one portion of the zone is dry, increasing the runtime may overwater the rest of the lawn while leaving the original coverage defect unresolved.
Related guides
See one zone has low pressure, sprinkler head too low, and our Grosse Pointe sprinkler repair service.
Authoritative resource
EPA WaterSense recommends correcting sprinkler obstructions and scheduling each zone for its specific conditions. EPA WaterSense
