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Why Do Florida Properties Overwater Most in the Fall?

Because October Sets a Schedule December Doesn't Need

15 min read Irrigation Managers

By Jon Peters, Founder and General Manager, Irrigation Managers. 33 years in irrigation technology and agronomy.

As of September 30, 2026. The South Florida Water Management District's (SFWMD) year-round landscape watering rule is in effect across Southwest Florida. The Lee and Collier water shortage warning was lifted June 4. NOAA has an El Niño Advisory in place heading into the dry season.

On June 4, 2026, SFWMD lifted the water shortage warning it had placed on Lee and Collier counties in February. The Lower West Coast had picked up 4.46 inches of rain since May 15, more than 140 percent of normal, and Lower Tamiami Aquifer levels rose about three feet.[^1]

That was the rainy season doing its job. The National Weather Service dates it May 15 to October 15 in Southwest Florida.[^2] In about two weeks, the calendar says it ends.

But a date on a calendar is an average, and our sandy soils hold very little water. In my experience, a few dry days can change what a landscape needs, and a wet week can change it back.

What happens next is predictable. The rain stops, the turf starts to look a little tired, and someone turns the controller up. In October, that can be the right call. By December it's usually the wrong one, and on most properties nobody comes back to turn it down.

That's the fall overwatering problem. It isn't a mistake anyone makes on purpose. It's a schedule that was right for a few weeks and then kept running all winter. The fix isn't a better calendar. It's a schedule that follows the weather.

Key Takeaways

  • Need rises when the rain stops, then falls. In Fort Myers, UF/IFAS puts October's net irrigation requirement at 3.0 inches, higher than any month from June through September, then 1.8 inches in December and January, 40 percent below October.[^3]
  • Dates are a plan, not a schedule. Sandy soils drain quickly, so adjust to actual rain and the forecast for the next few days.
  • Winter guidance is far less water than most schedules apply. UF guidance for December through February is one-half to three-quarters of an inch every 10 to 14 days.[^4] Watering every allowed day under a two-day-a-week rule runs about three to four times that often.[^5]
  • Overwatering costs turf. UF/IFAS says it "greatly increases disease susceptibility and thatch buildup and leads to a shorter root system."[^6]
  • This winter may be wetter. NOAA gives a very strong El Niño better than 90 percent odds,[^7] and strong El Niño winters have historically brought well above average dry-season rainfall to Florida.[^8]

What Actually Changes in Southwest Florida in the Fall?

Once the rain stops doing most of the work, irrigation need jumps briefly, then falls through November and December as temperatures and evapotranspiration drop.

UF/IFAS has calculated the long-term monthly net irrigation requirement for Florida lawns by city. Here is Fort Myers:[^3]

Month Net irrigation requirement (inches) What's happening
July 2.4 Rainy season carries most of the load
August 2.4 Rainy season
September 2.2 Rainy season, tapering
October 3.0 Rain tapers off on average; need jumps
November 2.4 Cooler, shorter days
December 1.8 40% below October
January 1.8 Winter low

Definition — net irrigation requirement: Net irrigation requirement is plant water use minus the rain that stays in the root zone. It is the water a landscape needs from irrigation.

Definition — evapotranspiration (ET): Evapotranspiration is the water a landscape loses to the atmosphere through evaporation from the soil and transpiration through the leaves. It falls in Florida's cooler months.

These are 30-year averages, so they cannot see this week's rain. Look at the shape of that table anyway. October is a spike, not a new normal. A property that raises its schedule to meet October and leaves it there is programmed for a month that ends on October 31.

Why Does the Schedule Get Stuck in October?

Because "set it and forget it" is the default on most properties, and in Florida the legal watering days become the schedule, whether the plants need them or not.

SFWMD's year-round landscape irrigation rule limits watering to two or three days a week, depending on local ordinance, with no watering between 10 a.m. and 4 p.m.[^5] Some local rules are stricter. Unincorporated Lee County, for example, was limited to one day a week from February 1 through May 31, 2026.[^9] Those rules set a ceiling. On a lot of properties they've become the floor. If the ordinance allows Wednesday and Saturday, the controller runs Wednesday and Saturday, all year.

Here's the arithmetic for winter:

  • Two days a week is about 8 to 9 watering days a month.
  • UF guidance for December through February, as published by the Southwest Florida Water Management District, is one-half to three-quarters of an inch every 10 to 14 days,[^4] or about 2 to 3 watering days a month.

That's roughly three to four times as many watering days as the guidance calls for, before you count how long each one runs. On a three-day-a-week ordinance the gap is wider. The guidance is a starting point. Rain and the forecast decide the actual day.

Nobody on the property is doing anything against the rules. That's why it goes unnoticed.

What Does Winter Overwatering Do to a Florida Landscape?

It weakens turf: shallower roots, more thatch, more disease and more weeds, which then look like a reason to water more.

UF/IFAS puts it directly: overwatering "greatly increases disease susceptibility and thatch buildup and leads to a shorter root system." The same publication links overwatering to dollarweed and sedges.[^6] The Southwest Florida Water Management District, citing UF research, warns that overwatering in winter can encourage pests and disease.[^4]

On St. Augustinegrass, a common lawn grass here, the winter disease to know is large patch. UF/IFAS says it is most likely from November through May, and that excessive irrigation can trigger it when the leaves stay wet for 48 hours or more.[^10] Cool, humid winter nights plus extra irrigation keep leaves wet longer.

Nothing floods. The turf thins out over the winter, weeds move in, and in March the landscape committee asks why the property looks worse after a season of watering on every allowed day.

What Does El Niño Mean for This Dry Season?

It may mean more winter rain than usual in Florida, which lowers irrigation need further and makes a fixed schedule even more wasteful.

On September 10, NOAA's Climate Prediction Center gave a very strong El Niño better than 90 percent odds for fall and winter 2026-27.[^7] According to NWS Melbourne, during strong El Niños such as 1982-83 and 1997-98, "storminess is greatly increased over Florida."[^8]

That's a historical pattern, not a guarantee. But a schedule that doesn't respond to rain this winter will be further off than usual. A rain sensor helps on the days it rains. It doesn't help on the dry, cool days in between, when plants simply need less. That adjustment has to come from the schedule itself.

Before the rain stops: know your number

The rainy season is about to end, and someone is about to turn the controller up. The properties that come through the winter looking best won't be the ones that picked the right run time on one date. They'll be the ones with a water use analysis baseline: measured water need, peak demand and seasonal adjustment for every zone, so the schedule can follow the season, and the weather, as they change.

Request a water use analysis for your Southwest Florida property →

What Should the Fall Adjustment Look Like?

Raise irrigation if the rain actually stops, then bring it down in stages through November and December, based on ET and real conditions, not on the calendar of allowed days.

  1. Establish the baseline before you change anything. Know what each zone applied during the rainy season and what it needs going into the dry season. Water need is this season's ET minus rainfall, multiplied by the irrigated area, so measure the area if you don't know it.
  2. Check uniformity zone by zone. Start with the heads: are they the same type in each zone, with matched nozzles? In my experience, the average installed system runs at about 50 percent distribution uniformity, which matches what the Irrigation Association found across more than 6,800 audits.[^11] EPA guidance calls for at least 65 percent.[^12] Poor uniformity is why dry spots push the schedule up for the whole zone.
  3. Repair before you re-water. Storm season and mowing leave broken, tilted and buried heads. Fix them before adding water.
  4. Plan the October increase, and expect to change it. Plan to meet October if the rain stops, and plan the reductions for November and December, but treat those dates as a plan. Sandy soils hold little water and drain quickly, so a few dry days can change everything, and a wet week can mean skipping cycles. Check real conditions and the forecast for the next few days, and adjust to them.
  5. Bring it down in November and December. Fort Myers need falls 40 percent from October to December.[^3] The water you apply should fall with it, as conditions allow.
  6. Water deeply and as infrequently as you can. UF/IFAS recommends one-half to three-quarters of an inch per irrigation,[^4][^6] rather than light runs on every allowed day. Because of distribution uniformity, in my experience it takes about three-quarters of an inch to an inch applied to get deep penetration across the zone. One-half inch is not terrible, but it is not quite enough.
  7. Water before sunrise. It keeps leaf-wet hours short.[^6][^10]
  8. Watch the turf for real stress signs. UF/IFAS lists folded leaf blades, a blue-gray tint and footprints that stay visible.[^6] Water when you see them, not because it's Wednesday.
  9. Report against the baseline every month. What you tell the board should come from measured water use.

You can look up ET and rainfall for your property with our free ET and rainfall lookup tool.

Who Is Most Exposed Right Now?

HOAs, condominium associations, commercial and institutional campuses, parks and community golf courses with large turf areas and many zones.

Every zone is its own microclimate: full sun, shade under oaks, a berm, a retention pond edge, heat off a parking lot. The more zones a property has, the more a single seasonal schedule is wrong somewhere, and a schedule that never changes is wrong in all of them for months.

What Should Florida Property Managers Do in the Next 30 Days?

  • ☐ Pull rainy-season water use from the controller and meter, with run times by zone.
  • ☐ Walk the property after the last big rains and log broken, tilted and buried heads by zone. Check head types and nozzles while you are there.
  • ☐ Plan your October increase and your November and December reductions, then check the forecast every few days and change the plan when the weather does.
  • ☐ Move start times before sunrise if any zones run late in the day.
  • ☐ Confirm your local watering days under the SFWMD year-round rule and your local ordinance, and treat them as a maximum.
  • ☐ Look up current ET for your site and compare it to your schedule.

In my experience, what I find in a Florida HOA's controller in January is what was there in October. Landscape maintenance teams and the people operating controllers don't make changes until an obvious problem shows up, and overwatering isn't an obvious problem to anyone who isn't trained in horticulture or agronomy. It doesn't look like a dry spot, so its effects are often misunderstood and misdiagnosed. Sometimes the response is to add more water, which makes the problem worse.

Supplying water to plants when they need it is the key to everything. That means understanding plant demand and how it changes through the season. Soil conditions change the diagnosis in specific ways, but the basic guidelines almost always apply.

St. Augustinegrass spreads by stolons, aboveground stems.[^13] UF/IFAS says overwatering leads to a shorter root system and more disease.[^6] In winter, the disease to watch for is large patch, which UF/IFAS says is most likely from November through May and can be triggered by excessive irrigation and leaves that stay wet for 48 hours or more.[^10] A schedule left running on every allowed day all winter keeps the leaves wet longer than the turf needs, and the turf thins as a result.

How Irrigation Managers Handles the Florida Fall Transition

Irrigation Managers is an irrigation management firm built on agronomy, not plumbing, led by Jon Peters, an agronomist with 33 years in irrigation technology and agronomic principles. We are on site when a property needs us, and we manage remotely where that keeps costs down for our clients. We work directly with property owners and as a white-label partner to landscape maintenance contractors.

Our framework is Analyze, Implement, Manage (AIM):

  • Analyze: a water use analysis establishing baseline need, peak demand and seasonal adjustment for every site.
  • Implement: system configuration, controller programming and base scheduling built from measured uniformity, plant demand and the legal watering window.
  • Manage: 24/7 proactive monitoring, fault and alert routing, and ongoing adjustment as the season and the weather change, with reports comparing performance to your baseline.

The goal is consistent, healthy turf and plantings across every zone, all year. In my experience, most sites use at least double the water their plants need, and on heavily overwatered sites this approach cuts water use by 50 percent or more.

The rainy season is about to end, and in Fort Myers, need drops 40 percent from October to December. The schedule should follow both the season and the weather.

Request a Water Use Analysis →

Frequently Asked Questions

How often should I water my lawn in Southwest Florida in the winter?
Less often than in summer. UF guidance published by the Southwest Florida Water Management District is one-half to three-quarters of an inch every 10 to 14 days in December, January and February. Water when the turf shows stress, before sunrise, within your local watering days, and adjust to rain and the forecast.

When does the rainy season end in Southwest Florida?
The National Weather Service puts it at May 15 to October 15. That is an average. After the rain stops, irrigation need rises for a few weeks, then falls through November and December.

What are the watering restrictions in Lee and Collier counties right now?
As of September 30, 2026, SFWMD's year-round landscape irrigation rule applies: two or three days a week depending on local ordinance, with no watering between 10 a.m. and 4 p.m. The water shortage warning for Lee and Collier was lifted June 4, 2026. A Modified Phase II order remains for private Mid-Hawthorn Aquifer wells in northeastern Cape Coral. Check SFWMD and your local government before changing schedules.

Why is my lawn getting worse in winter when we water every day we are allowed?
Winter turf needs less water, not more. Overwatering increases disease, thatch and weeds and shortens roots. Uneven coverage also plays a part: with average distribution uniformity near 50 percent, dry spots push the schedule up for the whole zone while the rest stays too wet. The fix is deeper, less frequent watering before sunrise, based on ET and real conditions, plus repairs.

Does El Niño change how I should water this winter?
It may. Strong El Niño winters have historically brought well above average dry-season rainfall to Florida, according to NWS Melbourne. That is not a guarantee, so watch the actual weather and adjust.

References

[^1]: South Florida Water Management District, SFWMD Rescinds Water Shortage Warning for Lee and Collier Counties, June 4, 2026. https://sfwmd.gov/news-events/news/sfwmd-rescinds-water-shortage-warning-lee-and-collier-counties

[^2]: National Weather Service Tampa Bay, Rainy Season. https://weather.gov/tbw/rainyseason

[^3]: Consuelo C. Romero, Bernard Cardenas and Michael D. Dukes, Net Irrigation Requirements for Florida Turfgrass Lawns: Part 3, Theoretical Irrigation Requirements (AE482), UF/IFAS Extension, Table 4, Fort Myers (30-year averages). https://ask.ifas.ufl.edu/publication/AE482

[^4]: Southwest Florida Water Management District, Overwatering in Winter Can Encourage Pests and Disease, WaterMatters Magazine, July 19, 2018. https://www.swfwmd.state.fl.us/blog/watermatters-magazine/45/skip-week-watering-healthier-lawn

[^5]: South Florida Water Management District, Landscape Watering Restrictions, updated June 4, 2026. https://www.sfwmd.gov/community-residents/landscape-irrigation

[^6]: Laurie E. Trenholm, J. Bryan Unruh and John L. Cisar, Watering Your Florida Lawn (ENH9/LH025), UF/IFAS Extension. https://ask.ifas.ufl.edu/publication/LH025

[^7]: NOAA Climate Prediction Center, ENSO Diagnostic Discussion, issued September 10, 2026. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml

[^8]: National Weather Service Melbourne, Florida Dry Season Rainfall and El Niño-Southern Oscillation (ENSO). https://www.weather.gov/mlb/enso_florida_rainfall

[^9]: WGCU News, Watering now one day a week through May in unincorporated Lee, January 21, 2026. https://www.wgcu.org/environment/2026-01-21/watering-now-one-day-a-week-through-may-in-unincorporated-lee

[^10]: Monica L. Elliott and Philip F. Harmon, Large Patch Disease in St. Augustinegrass (SS-PLP-5/LH044), UF/IFAS Extension. https://ask.ifas.ufl.edu/publication/LH044

[^11]: Brent Mecham, Using Distribution Uniformity to Evaluate the Quality of a Sprinkler System, Irrigation Association, 2004. https://www.irrigation.org/IA/FileUploads/IA/Resources/TechnicalPapers/2004/UsingDistributionUniformityToEvaluateTheQualityOfASprinklerSystem.pdf

[^12]: U.S. EPA WaterSense, WaterSense at Work, Section 5.3: Irrigation, 2023. https://www.epa.gov/system/files/documents/2023-05/ws-commercial-watersense-at-work_Section_5.3_Irrigation.pdf

[^13]: UF/IFAS Extension, St. Augustinegrass for Florida Lawns (ENH5/LH010). https://edis.ifas.ufl.edu/lh010