Why Your Texas Lawn Has Dry Spots Even With Irrigation Running: Diagnosing Pressure, Coverage, and Head Issues
Short Answer: If your irrigation system runs on schedule and your lawn still has brown dry spots, the cause is almost always one of four things: misaligned or blocked sprinkler heads, pressure that is too low or too high for the head design, gaps in coverage between heads, or a zone valve issue that is making one zone run shorter than it should. Each one looks slightly different and each one is fixable, usually for less than the cost of resodding the dry area. A 30-minute walk-through with the system running tells us exactly which issue applies and what it costs to repair.
“I am watering plenty but it still has brown spots.” This is one of the most common calls we get in June and July across Bryan and College Station. The homeowner is doing everything right on paper. The system runs the schedule. The lawn still has obvious patches that are crisp and brown while the rest of the yard looks fine.
The problem is rarely about how much you are watering total. It is almost always about how unevenly that water is reaching the ground. We want to walk you through how to diagnose this on your own property, what each problem looks like, and what it takes to fix.
The Self-Inspection That Reveals Almost Everything
Before we get into specific problems, here is the inspection that surfaces 90 percent of dry spot causes. Pick a morning when you have 30 minutes free. Walk to the controller and put it in manual mode. Run each zone for 3 to 5 minutes while you walk it. Watch each head individually. Take notes (your phone camera is great for this).
You are looking for several things at once. Heads that are not popping up at all. Heads that are spraying onto the driveway, the house, or the fence. Heads that are tipped or rotated off their intended pattern. Spray patterns that are blocked by overgrown shrubs or accumulated lawn debris. Areas where two adjacent heads do not overlap, leaving a gap in coverage. Heads that are misting heavily (too much pressure) or barely throwing water (too little pressure). Sunken rotors where the spray hits surrounding turf instead of going up and over.
This walk takes about 30 minutes for an average Brazos Valley property and it usually surfaces three to six fixable issues that together explain almost every dry spot in the yard.
Problem One: Misaligned or Damaged Heads
The most common irrigation problem on residential properties is heads that have been moved by mower wheels, foot traffic, kids, or root pressure. The head pops up but the spray pattern no longer hits where it was designed to hit. You water the driveway instead of the corner. You water the house siding instead of the bed in front. You leave a 6 foot strip dry between heads that used to overlap.
The fix is usually straightforward. Spray heads can be rotated by hand to point the right direction. Rotor heads have arc adjustment screws that set the start and end of the rotation. Damaged heads (cracked bodies, snapped risers, plugged nozzles) need replacement. Most of these repairs run $15 to $40 per head including parts and labor.
If you have a property where the same area has gone dry year after year, this is the first thing to inspect. We frequently find that the head responsible was knocked off pattern two or three seasons ago and has been creating the same dry spot ever since.
Problem Two: Pressure Issues
Sprinkler heads are designed to operate within a specific pressure range. Most residential spray heads work best between 30 and 40 PSI. Most rotors between 40 and 60 PSI. Outside those ranges, performance degrades dramatically.
Too low pressure. Spray heads do not reach their full radius. Rotors do not rotate properly. Coverage shrinks across the zone. The lawn looks dry in patches that map to incomplete spray patterns. This is common on properties where the supply line was undersized at installation or where a leak somewhere in the system is pulling pressure away from active zones.
Too high pressure. Water atomizes into fine mist that drifts away on any breeze. You can hear the difference (a high-pitched hiss instead of the normal water sound). Heads break more often. Coverage is uneven because mist is going wherever the wind blows. This is common on properties with strong municipal water supply that was never regulated down at the system.
A simple pressure gauge attached to a hose bib gives you a starting point. A more thorough test at each zone tells us exactly where the problem is. Pressure regulators or pressure-regulating heads usually solve high pressure problems. Pump issues, supply line problems, or leak repairs solve low pressure problems.
Problem Three: Coverage Gaps
Sprinkler systems are designed with a principle called head-to-head coverage. Each head should throw water far enough that its spray reaches the next head. The overlapping spray from two heads produces even coverage between them. If the heads do not overlap, you get a dry stripe halfway between them.
Coverage gaps come from several sources. Installer error (heads spaced too far apart from the start). Aftermarket changes (the property owner added landscaping that blocked spray patterns). Hardware changes (a head was replaced with a smaller nozzle that does not throw as far). Pressure problems (heads not reaching their full design distance).
The catch-can test confirms coverage. Place six to ten empty tuna cans or yogurt containers across a zone in a roughly even grid. Run the zone for 15 minutes. Measure how much water collected in each can. Healthy coverage shows roughly equal amounts in every can (within 25 percent). Significant coverage gaps show as cans with much less water than others. The dry spots in your lawn will line up with the low-collection cans almost perfectly.
Fixing coverage gaps usually requires adding heads, upgrading existing heads to longer-throw nozzles, or relocating heads that are no longer in the right place. We can usually solve coverage problems with a few hundred dollars of parts and a couple of hours of labor on a typical residential lawn.
Problem Four: Zone or Valve Problems
Sometimes the issue is not a head at all. It is a valve. A zone with a sticking valve may run for less time than the controller is asking. A diaphragm that does not fully open can deliver lower pressure to its entire zone. A solenoid that intermittently fails may skip cycles without you knowing.
The diagnostic clue is consistency. If every head in a single zone is underperforming, the valve or the supply to that zone is the likely cause. If only some heads in a zone are off, the issue is with those specific heads.
Valve repairs are usually $50 to $150 each, depending on access. We rarely replace a whole valve manifold unless there is something fundamentally wrong with the original installation.
The Less Obvious Causes
A few less common issues we see on Brazos Valley properties.
Programming errors. The controller has the zone set for 10 minutes instead of 25. We see this when controllers were reprogrammed by a different person and not all the zones got the right values.
Rain sensor stuck on. A sensor that has not reset itself after a recent rain may be telling the controller to skip cycles even though the ground is dry.
New construction or landscaping changes. Adding a patio, a planting bed, or a structure can block spray patterns from heads that used to work fine.
Soil compaction or hydrophobic soil. Water lands on the surface but cannot soak in. This shows up as runoff during cycles and dry soil underneath. Aeration is the fix, not more water.
What This Costs to Fix
Most dry spot problems we resolve in Bryan and College Station fall in the $150 to $500 range for a complete fix, including diagnosis. Routine head replacements and adjustments are usually under $200. Pressure correction or valve repairs can run a bit higher. Major coverage redesigns (adding zones or significantly redesigning head placement) can run higher still but those situations are rare.
Compare that to the cost of letting dry spots compound through summer. Sodding 100 square feet of dead lawn often runs $300 to $600. Replacing 500 square feet can be $1,500 or more. Plus the months of staring at a brown patch while you save up for it.
What to Do Next
Walk your zones this week if you have the time. If you find one or two clear issues, you can often handle them yourself with parts from any irrigation supply store. If you find multiple problems or you are not sure what you are looking at, that is exactly the kind of property we visit.
Call us at 979-412-3624 or visit cclawnservice.com. We will do a full system audit, document what we find with photos, quote each repair separately so you can choose what to address now and what to defer, and have the system working the way it should well before the heart of summer. We serve Bryan, College Station, and the broader Brazos Valley.