One corner of the lawn looks thirsty while another squishes underfoot. It is tempting to add five minutes to the sprinkler timer and hope the brown area catches up. But uneven sprinkler watering calls for a closer look at where the water lands—and what happens after it reaches the ground.
This walkthrough helps you separate a coverage problem from a runoff or persistent-wetness problem. You will record a few observations, compare catch-cup readings, and choose a useful next step. A brown area describes the grass’s appearance; it does not, by itself, establish the cause or diagnose the turf disease called brown patch.
Start with two questions, not a longer watering cycle
Ask: “Does the dry-looking area receive less sprinkler water?” and “When does the soggy area become wet?” Those questions lead to different checks. A photograph of brown grass cannot tell you whether a head is blocked, the ground is slow to absorb water, or something unrelated to irrigation needs attention.
Choose one affected controller station for the first inspection. If you do not know its number, use our guide to mapping sprinkler zones before testing. Add separate problem markers for the brown area and wet area in the Sprinkler Zone Planner. They may not even belong to the same station.
Give each observation a location and time: “Front lawn by driveway, dry-looking before the test” or “Patio corner, puddle appeared six minutes into Station 2.” Note recent rain, and photograph both areas from a repeatable viewpoint. This creates a record you can compare instead of relying on memory.
Watch a short test from the lawn
Follow your controller’s instructions for running one station manually, when local watering rules allow. Look at the spray from several positions. Does a head remain low or tilted? Does a shrub intercept the water? Does a stream land on the sidewalk? Stop the test if water pools or runs off; there is no benefit in completing an arbitrary test duration while the area floods.
EPA WaterSense’s Sprinkler Spruce-Up guidance recommends checking damaged heads, spray direction, and coverage. It also identifies pooling between irrigation cycles as a possible sign of a leak. A persistent wet spot is a reason to investigate, not proof that a particular pipe or valve has failed.
Use the table below to decide what to record next. Treat it as a starting point, not a diagnosis.
| What you observe | Next useful check |
|---|---|
| A shrub blocks water before it reaches the brown area. | Record the head and obstruction; compare coverage after an appropriate correction. |
| The area becomes wet only after several minutes of spraying. | Record when pooling starts and where runoff travels. |
| One spot stays wet between cycles. | Note rain and other water sources; arrange a leak or drainage assessment if it persists. |
| Spray looks weak, irregular, or misty. | Flag the affected heads for a nozzle, pressure, and coverage check. |
| Coverage appears similar, but the grass still looks different. | Compare measured output before changing the timer; seek lawn-specific advice if irrigation does not explain it. |
Use catch cups to check uneven sprinkler watering
A catch-cup test measures water arriving at several points during the same run. It does not measure how much the soil absorbs or diagnose why grass is brown. That distinction matters when a cup sits beside a puddle: the cup records incoming sprinkler water, while the puddle may also include runoff from elsewhere.
For a simple homeowner comparison, use identical straight-sided, flat-bottom containers with level openings, or purpose-made irrigation catch cups. Distribute them across the area served by one lawn-sprinkler zone. Include representative positions through the zone, rather than placing every cup in the problem corner. Label the positions on your sketch. This method is for overhead sprinklers; it is not a drip-emitter test.
Start with empty cups, run the station for a measured interval in calm conditions, then record each water depth using the same units. Keep the interval the same for every cup. If pooling forces you to stop early, use the actual elapsed time. Repeat a test affected by a tipped cup, rain, or gusty wind before drawing conclusions.
EPA’s watering tips describe using containers to measure sprinkler output. For this troubleshooting exercise, keep the individual readings alongside the average. The differences are the information you are looking for.
Worked example: the average hides a dry corner
Imagine four identical containers placed at different points in one zone. After a 15-minute test, the homeowner records the following illustrative measurements. Four readings keep this example easy to follow; they are not a full professional irrigation audit.
| Cup position | Depth after 15 minutes |
|---|---|
| A — near the dry-looking corner | 0.10 inch |
| B — beside the path | 0.20 inch |
| C — center of lawn | 0.30 inch |
| D — near the wet-looking edge | 0.40 inch |
The average depth is (0.10 + 0.20 + 0.30 + 0.40) ÷ 4 = 0.25 inch. The average application rate is 0.25 ÷ 15 × 60 = 1 inch per hour. That rate describes this example’s measured output, not a recommended watering amount.
Now compare the ends of the range: Cup D caught four times as much water as Cup A. If output stayed steady and the homeowner doubled the runtime, the estimated readings would become 0.20, 0.40, 0.60, and 0.80 inch. The four-to-one difference would remain. Longer watering would add water everywhere without resolving the uneven distribution.
This is why entering only the 0.25-inch average into a runtime calculator can miss the most useful finding. Record the average and test duration in the planner, but keep the individual depths in your notes. Investigate the coverage difference, correct confirmed problems, and repeat the test before treating the calculated runtime as a suitable schedule.
What if the cups are similar, but one area stays soggy?
Similar readings shift your attention to what happens at ground level. Water arriving at a similar rate does not guarantee similar absorption or drainage. Note whether the wet area is downhill from the other cups, whether water travels across it, and whether the problem follows rain as well as irrigation.
For runoff associated with slow absorption, dividing the intended watering time into shorter cycles with soaking breaks may help. Utah State University Extension’s turfgrass guidance discusses repeated short cycles when puddling or runoff occurs. Use locally appropriate timing for your soil and landscape; this is not a reason to add extra total watering time.
For example, splitting a hypothetical 12-minute total into three 4-minute runs still gives 12 minutes of watering. The breaks add elapsed time, not sprinkler runtime. This is an explanation of the arithmetic, not a schedule for your yard. The appropriate cycle length and soaking interval need observation and local guidance.
If the ground stays saturated between cycles, do not keep experimenting with longer runs. A leak, drainage issue, or another water source needs assessment. If measured coverage does not explain the brown grass, a local extension office or qualified lawn professional can help investigate other causes.
Turn your observations into a useful repair request
Before calling for help, prepare a short record: controller station, problem location, date, recent rainfall, time until pooling, and catch-cup results. Attach the same-view photographs and a copy of your zone map. A specific request—“Please check uneven output in Station 2 and persistent pooling by the patio”—is easier to act on than “My lawn needs more water.”
The EPA landscape inspection checklist provides additional checks and identifies issues suited to professional attention. Flag suspected leaks or damaged equipment; leave underground connections, valve repairs, and pressure diagnosis to someone equipped for that work.
If work is recommended, use the Home Project Budget Planner to separate diagnosis, confirmed repairs, and optional upgrades. Ask what each proposed change is intended to fix. That keeps an inexpensive obstruction correction separate from a larger redesign.
Make one change, then compare
Keep the original measurements, document the correction, and repeat the same test positions under comparable conditions. Look for improved coverage or less runoff first; grass color is not an instant test result. Update the Sprinkler Zone Planner with the new observations and print a fresh reference if the plan changes.
Your next step should follow the evidence: investigate low readings, assess persistent wetness, or seek a broader lawn diagnosis. A few labeled measurements can make that choice much clearer than another five minutes on the timer.