The answer to 'sprinkler system thin grass' is that a common cause is improper sprinkler coverage or water distribution. Symptoms include patchy, thinning grass in areas not receiving adequate water from the sprinkler system. Solutions may include adjusting sprinkler heads, increasing water pressure, or adding additional sprinkler zones to ensure even coverage across the lawn.
If the problem persists or you're unsure of the cause, it's best to consult a professional landscaper or sprinkler system specialist. They can assess your system, identify the underlying issues, and recommend the appropriate repairs or modifications to restore a healthy, lush lawn.