Florida afternoon storms are not a rumor. The Florida Climate Center’s 1991–2020 normals for Orlando show roughly 51 inches of rain a year, with June, July, and August each averaging more than 7 inches. Rain sensors exist so an irrigation controller can skip a cycle when the landscape has already been watered. Myths creep in when homeowners expect a sensor to fix dry zones, broken heads, or a blank controller. This guide separates useful checks from wishful thinking.
Orlando West Irrigation is a matching service for residential irrigation techs in the west Orlando area. We do not sell or install a particular sensor brand, and we do not promise a result from this article.
Is a rain sensor required in Florida?
Yes, for automatic systems. Florida Statutes section 373.62 says anyone who installs an automatic landscape irrigation system must properly install, maintain, and operate technology that inhibits or interrupts the system during periods of sufficient moisture. The same section requires a licensed contractor working on an automatic system to test those devices and repair or replace them if they are missing or not working. The St. Johns River Water Management District’s watering restrictions page also says automatic systems installed after May 1991 must have a rain sensor device or switch.
UF/IFAS Extension’s publication on rain sensors (AE221) notes that a soil-moisture sensor controller or an evapotranspiration (ET) controller can serve as the shutoff device instead of a classic rain sensor.
What does a rain sensor actually do?
According to UF/IFAS, a rain sensor is a small device wired to the controller and mounted where it is exposed to rainfall. After a set amount of rain, it interrupts the controller’s common wire, which disables the solenoid valves until the sensor dries out. It is a skip tool for schedules. It is not a coverage guarantee and not a substitute for heads that no longer throw water to the sidewalk.
UF/IFAS describes three main types:
- Weight-based cups that shut the system off when enough water collects. Debris, frogs, or birds can also trip them, so they need more upkeep.
- Conductivity sensors that detect water in a small dish with electrodes. Debris can cause problems here too.
- Expanding disks, the most popular type, which swell as they absorb rain and trip a switch. They come in wired and wireless versions; UF/IFAS notes wireless models can be mounted up to about 300 feet from the receiver.
What are the common rain sensor myths?
Myth: “If I have a rain sensor, I cannot get dry patches.” False. Sensors do not aim heads, repair valves, or fix a zone that never opened. Dry patches still need dry zone triage.
Myth: “The sensor is broken because the grass is brown.” Maybe, or the schedule never ran, a valve failed, or disease followed a wet week. Note whether automatic runs are being skipped while manual runs still work.
Myth: “A Wi-Fi weather skip replaces a field sensor.” App-based weather skips can help, but storms are very local and the weather data may not match your street in Winter Garden or Clermont. If the app says a zone ran and the yard stayed dry, put that in the notes for a controller match.
Myth: “After any storm the system should stay off for a week.” UF/IFAS research found that average rain-sensor dry-out time was about 19 hours after rain stopped, with no meaningful difference between the brands tested. A sensor that keeps the system off for days after a modest shower may be mounted badly, set too high, clogged, or stuck.
Myth: “Set it to the highest number so it does not trip too often.” UF/IFAS recommends the opposite: use the smallest practical set point (1/8 inch is the lowest on most devices) and not more than 1/4 inch, because smaller settings saved the most water in their studies.
Where should a rain sensor be mounted?
UF/IFAS says the sensing part should get unobstructed rainfall but sit outside the path of sprinkler spray. It is often mounted near the roofline on the side of a building, but not where water runs straight off the roof. Trees, overhangs, and awnings should not block it. Fence posts or deck rails can work where vandalism is not a concern. A sensor tucked under a soffit, behind a gutter, or in a sprinkler’s spray will give misleading results.
How do I test a rain sensor?
UF/IFAS recommends checking a rain sensor at least once a year:
- If the controller has a sensor port or switch, make sure it is set to “Active,” not bypass.
- Start an irrigation zone.
- While it runs, spray the sensor with a garden hose.
- Cup and electrode sensors should stop the system almost immediately; expanding-disk sensors should stop it within a few minutes.
If nothing happens, UF/IFAS’s troubleshooting list includes cleaning the sensor, moving it to a better spot, and checking that the wires are intact. For disk sensors, replace the disks, which UF/IFAS suggests doing at least every two years. For wireless sensors, check the receiver connection and replace the battery. If none of that works, the unit may need replacing.
What should I check before requesting a match?
- Look at the sensor (often on an eave or fence line): debris, paint overspray, or disks that never seem to dry can keep it stuck “wet.”
- Check whether the controller shows a rain or sensor indicator, and whether the sensor switch is on bypass.
- Try a manual zone run if it is safe. Does water flow when automatic runs will not?
- Write down the last heavy storm date and when you first noticed skipped cycles or dry turf.
Those four notes are enough for a productive quote request. If the answer is “manual works, automatic never does, and the sensor indicator is always on,” you are likely looking at a sensor or controller fix rather than sprinkler repair.
What about watering days and shortage orders?
A rain sensor does not change your allowed days. SJRWMD sets watering days and hours, and those can tighten during a water-shortage order. When we last checked, a Phase III shortage covered the portions of Lake County within the district, which matters for Clermont and Minneola homeowners. Read our watering days and restrictions page for the concepts and the official link.
What if I turned the system off for travel?
If you switched the controller off while away, the sensor may not be the issue at all; see seasonal start-up / shut-down. Vacant home watch is SafeNest, not irrigation matching.
Where do we match irrigation requests?
We match residential irrigation requests in Winter Garden, Horizon West (including Hamlin and Waterleigh), Clermont, and nearby villages. The tech confirms scope, price, and schedule. We do not publish a shop address, reviews, or license claims. Mowing stays with Lawn Care; Soft Wash, Pool, and Pest are separate services.
Request a local irrigation tech · head vs valve vs controller · HOA dry zones
Sources
- UF/IFAS: Residential Irrigation System Rainfall Shutoff Devices, or Rain Sensors (AE221)
- Florida Statutes section 373.62
- SJRWMD watering restrictions
- Florida Climate Center: Orlando 1991–2020 normals
Questions from this guide
- Do rain sensors stop a Florida afternoon storm from flooding the yard?
- A working sensor should skip a cycle after rain. The tech checks it.
- Broken head vs bad valve vs dead controller?
- Different fixes. Tell us what you already tried.
- Is this lawn care or irrigation?
- Irrigation. Mowing is a different match.