Most of the repair calls we get from June through September trace back to the same root cause: heat plus humidity plus a system being asked to run more often than it did in April. The Central Florida summer is brutal on irrigation systems, and it is even harder on the grass those systems are watering.
What the Heat Does Underground
PVC pipe expands and contracts with temperature. Pipes buried four to six inches under sod are mostly insulated, but the fittings closest to the surface — backflow assemblies, valve manifolds, pop-up risers — feel the swing. Repeated expansion loosens threaded joints. A joint that was watertight in March will sometimes start weeping in August.
Solenoid coils run hotter in summer. The coil is the small electrical part on top of each valve that opens the valve when the controller sends a signal. Heat shortens its life. A solenoid that has been running for six years is far more likely to fail in July than in November, and "the system stopped running on one zone" is the most common July call we get.
And then there is lightning. Florida has the highest lightning strike density of any state in the country. A direct hit is rare. A nearby strike sending a surge through the underground wiring is not. After every major thunderstorm we hear from at least a few homeowners whose system was working yesterday and is dead now.
Your Lawn Is Working Harder Too
The dominant turfgrass in Central Florida is St. Augustine. It does best between 80 and 95 degrees. Once daytime highs climb above 95, which is most days from late June through August, it starts to stress, especially along sidewalks, driveways, and the south side of the house where soil dries fastest.
That stress is exactly what chinch bugs are waiting for. They are the most damaging insect pest of St. Augustine in Florida, and they explode in numbers during hot dry summer weather. The dry strip of lawn next to the driveway is usually where they show up first. The damage looks like drought stress, so most people respond by watering more. Watering does nothing for chinch bugs, and the extra water can trigger a second problem.
Overwatering in heat is how lawns get fungal disease. Wet grass plus high humidity plus warm nights is the formula for brown patch and gray leaf spot. The damage starts at the root, and by the time the brown rings are visible on the surface, the lawn is already in trouble. Watering at night is the single most common way homeowners cause this themselves.
How to Water in the Summer
The St. Johns River Water Management District, which covers Orange, Seminole, and surrounding counties, restricts residential irrigation to two days per week during daylight saving time. Your days depend on your address. Odd-numbered addresses water on Wednesday and Saturday. Even-numbered addresses water on Thursday and Sunday. Watering between 10 AM and 4 PM is prohibited year-round, and runtime is capped at one hour per zone per day.
Within those rules, a few things matter:
Water in the early morning. Between 4 AM and 8 AM is the window. The grass dries off before nightfall, which prevents fungus. The sun is not yet high, so evaporation loss is minimal. A system that finishes before sunrise is doing its job.
Water deeply, not frequently. Three-quarters of an inch to one inch of water per week is the target for St. Augustine, including whatever you got from rain. A system that runs longer twice a week trains roots to grow deep. A system that runs every day trains roots to stay shallow, and shallow roots are the first thing to die when the heat is brutal.
Check the rain sensor. Florida has required one on every system installed since 1991. If yours has not been replaced in ten years, it is probably stuck open or broken. Hold a wet hose against it for a minute. If the system does not pause, the sensor is dead, and the system has been ignoring rain for who knows how long.
When to Call
A dry patch that does not respond to watering, a wet patch on a day the system was not scheduled, a zone that is silent while the others run, a sudden bump on the water bill — those problems do not get better on their own in summer. They get worse fast, because the lawn is already under stress.
Call 407-774-6648 for a free estimate. We have been diagnosing summer sprinkler problems in Central Florida since 1972.