One part of the lawn looks dry, but the grass across the rest of the irrigation zone looks fine. It is tempting to add more minutes to the controller. Before you do, check whether the sprinklers are covering that patch evenly. A longer run can leave the dry area with more water while overwatering turf that was already getting enough.[4]
A quick walk-through and a simple catch-can test can help answer the useful question: does the dry spot need a schedule change, or is water not reaching it in the first place?
Key takeaways
- Check the sprinkler pattern before increasing the run time for a whole zone.
- Watch for tilted, blocked, broken, or misdirected heads, plus pooling that remains between irrigation cycles.
- Use identical straight-sided containers to compare how evenly one zone applies water.
- If coverage is uneven, identify the head, nozzle, obstruction, pressure, or layout issue before changing the schedule.
- If the catch-can test looks even, the cause may be outside the irrigation system, such as shade or soil conditions.
Start by finding the zone that waters the dry spot
Most in-ground systems run one zone at a time. Find out which zone includes the dry patch and which heads serve it. If the dry area and the wetter turf are actually on different zones, changing one controller setting will not affect both in the same way.
Make a simple note or sketch of the zone while the system is off. Mark the dry area, visible heads, nearby beds, sidewalks, and any places where water regularly pools. This gives you a useful reference when the zone runs and helps you describe the problem if you request a repair.
Watch one normal irrigation cycle
When the zone is scheduled to run, watch it operate from beginning to end. Avoid starting an extra cycle until you have checked the watering rules that apply to your address. For Florida properties, UF/IFAS notes that local governments and water management districts may set irrigation restrictions, and those requirements can vary by community.[2]
Look for clues that point to a coverage problem:
- A head stays low, leans, or does not rise fully.
- The spray is blocked by a plant, edging, or another object.
- Water shoots onto pavement, a wall, or a bed instead of the turf.
- A sprinkler produces a weak or irregular pattern while nearby heads spray normally.
- Water bubbles or pools around a head or joint while the zone is running.
- A puddle remains between irrigation cycles, which can be a sign of an underground leak.
EPA WaterSense recommends checking each zone for broken or misdirected heads, leaks, and water landing on hard surfaces. It also notes that each sprinkler should reach the head next to it for head-to-head coverage.[1]
Mark the location of a problem head with a small flag or take a clear photo. A photo of the running spray is especially useful when the issue is intermittent. Do not assume that a wet spot is proof the whole zone is overwatering; it may be a localized leak or a head that is aimed at the wrong place.[1]
Compare the zone with a catch-can test
If the spray pattern is hard to judge by eye, compare the water collected in several identical, straight-sided containers. UF/IFAS describes placing small cans in a line from a sprinkler toward the edge of its watering pattern, running the zone for 15 minutes, then checking whether the cans hold about the same amount. A recent UF/IFAS irrigation recap also recommends placing identical containers across a zone and comparing the collected water to assess how evenly it is being applied.[2][4]
- Choose one zone and place containers at several representative points, including near the dry patch and in healthier-looking turf.
- Run the test only when permitted. If you use the UF/IFAS 15-minute method, make sure that duration fits the irrigation rules for your property.
- Compare the water in the containers. You are looking for differences across the zone, not a universal number of minutes that every lawn should run.
This is a coverage check, not a complete irrigation audit. It can show that one area received less water during the test, but it cannot identify every reason why. Do not use a single test to set a permanent watering schedule. Turf needs and watering restrictions vary with factors such as rainfall, season, soil, shade, and the grass itself.[2][4]
What the results can tell you
If the containers near the dry patch collect noticeably less: inspect the closest heads first. A blocked or tilted head, clogged or damaged nozzle, poor spacing, or a pressure problem can create uneven delivery. UF/IFAS identifies head placement, blocked spray, and mismatched sprinkler types or application rates among the conditions that can leave one part of a zone drier than another.[3]
Do not solve a weak area by automatically lengthening the whole zone. UF/IFAS cautions that when one part receives less water, extending the run time may give the dry spot more water but overwater parts that were already receiving enough.[4]
If the containers collect similar amounts: the system applied water more evenly during that test. That does not prove the lawn has the right schedule, but it is a reason to pause before changing the controller. Consider whether the dry area differs in shade, soil, compaction, or turf condition. UF/IFAS explains that irrigation needs can vary within one landscape because of these site conditions.[2]
If you see pooling, a broken head, or several weak patterns: note what you found and arrange a repair inspection. EPA WaterSense advises homeowners who are unsure about a repair to contact an irrigation professional. Its guidance also identifies pooling between cycles as a possible sign of an underground leak.[1]
When to call for sprinkler repair
A homeowner can usually identify where a pattern looks wrong. Diagnosing why a zone has low pressure, a leaking underground line, a valve that will not close, or several heads with uneven output can require more than a controller adjustment. Countryside Lawn Care’s irrigation repair service lists sprinkler heads, underground leaks, valves, controllers, pressure, and coverage among the issues it handles.
When you request an estimate, share the zone number, where the dry area appears, whether the pattern changes during the cycle, and any photos or catch-can comparisons. That gives the technician a clearer starting point than simply saying the lawn needs more water. To discuss a repair, contact Countryside Lawn Care.
Frequently asked questions
Should I just run the sprinklers longer to fix one dry spot?
Not before checking coverage. If the rest of the same zone is already getting enough water, extending the whole run may overwater it. Compare the spray and, if appropriate, use a catch-can test first.[4]
How many containers do I need for a catch-can test?
Use several identical, straight-sided containers placed at representative points across the zone, including the dry patch. The goal is to compare the water collected in different areas. UF/IFAS does not make one container count a universal rule for every yard, so focus on a useful spread across the spray pattern.[2]
What if the lawn stays dry even though the test looks even?
Do not keep adding water by default. Shade, soil, compaction, turf type, and other site conditions can affect how a patch responds. If the cause is not clear, get the turf or irrigation system assessed before making a larger change.[2]
Check the spray before changing the schedule
A single dry patch is a reason to inspect the water pattern, not automatically a reason to run every sprinkler longer. Watch the zone, compare coverage, and note what is different near the stressed area. If the test points to a broken head, leak, pressure issue, or uneven system, get the cause checked before changing the whole lawn’s schedule.
