FL Irrigation Winterization & Spring Start-Up Guide
Freeze prep · Backflow preventer protection · Zone pressure test · FL WMD seasonal scheduling · Spring activation checklist
FL Freeze Risk by Region
Florida freezes are rare but devastating to unprepared irrigation systems. Even South Florida occasionally sees temperatures near freezing during January cold fronts. Damage to backflow preventers and exposed PVC can cost $500–$2,500 to repair.
- South FL (PBC/Broward/Miami-Dade) — Low; occurs once every 5–10 years
- SW FL (Naples/Fort Myers) — Moderate; 1–3 nights/year below 35°F
- Central FL (Tampa/Orlando) — Moderate; 2–6 nights/year below 32°F
- North Central FL (Gainesville/Ocala) — High; 5–15 nights/year below 32°F
- North/NW FL (Jacksonville/Tallahassee/Panhandle) — High; 10–25 nights/year below 32°F
- Temperature at which PVC sprinkler heads crack: Below 28°F for 4+ hours
- Temperature at which backflow preventers freeze: Below 32°F for 2+ hours (exposed)
FL Freeze Warning: When the National Weather Service issues a Freeze Warning (below 32°F) or Frost Advisory for your county, your irrigation backflow preventer is the most vulnerable component. An exposed, uninsulated RPZ or PVB can freeze and crack in a single overnight frost, flooding your yard when it thaws and requiring full replacement.
Freeze Prep Checklist — Before a Cold Front
Complete all critical items before temperatures drop below 35°F.
- Check NWS freeze forecast (CRITICAL): Monitor weather.gov for your county. A Freeze Warning means below 32°F for 2+ hours — take immediate action. A Frost Advisory means 33–36°F — protect backflow preventers.
- Wrap backflow preventer with insulation (CRITICAL): Use foam pipe insulation or a commercial backflow preventer cover bag on your RPZ, PVB, or DCVA. Do NOT use plastic bags — they trap moisture. Insulation bags cost $15–$40 at hardware stores.
- Locate and know how to close irrigation shutoff valve (CRITICAL): Find the main irrigation supply shutoff (usually near the backflow preventer or water meter). If a backflow preventer freezes and bursts, you need to shut off water immediately to prevent flooding.
- Turn irrigation controller to "OFF" or "Rain" mode (CRITICAL): Do NOT run your irrigation system during a freeze event — wet grass and plants freeze faster.
- Drain exposed above-ground pipe sections (IMPORTANT): Open drain caps or manual drain valves on any exposed above-ground PVC between the water meter and backflow preventer.
- Insulate exposed PVC risers and laterals (IMPORTANT): Wrap pump connections and riser pipes near exterior walls with foam pipe insulation and secure with waterproof tape.
- Check valve boxes for standing water (IMPORTANT): Open each valve box; if water has pooled inside, bail it out — standing water can freeze and crack solenoid valves and fittings.
- Test rain/freeze sensor function (RECOMMENDED): FL requires rain sensors on all new irrigation systems (FS §373.62). A freeze sensor will automatically suspend irrigation when temps approach freezing.
- Check pump (if applicable) for freeze protection (IMPORTANT): Most FL irrigation pumps are above-ground and vulnerable — wrap pump body and supply pipe.
- Notify tenants / HOA of temporary irrigation suspension (RECOMMENDED).
- Know your WMD watering day restrictions (RECOMMENDED): WMDs suspend year-round watering restrictions during freeze events — you may run extra irrigation before a hard freeze to protect plants.
- Inspect system within 24 hours after freeze (CRITICAL): Check backflow preventer for cracks/leaks, valve boxes for broken fittings, spray heads for cracked bodies, and main supply for wet ground indicating pipe breaks.
Backflow Preventer Freeze Protection — FL Code
Florida Plumbing Code §608 requires backflow prevention on all irrigation systems connected to potable water.
- RPZ (Reduced Pressure Zone) — most vulnerable to freeze; must drain or insulate (contains water-filled relief valve)
- PVB (Pressure Vacuum Breaker) — second most vulnerable; insulate bonnet, body, and supply pipe
- DCVA (Double Check Valve) — often buried, more protected; check above-ground ports
- Commercial backflow preventer inspection frequency: Annual (required by FL code)
- Cost to replace cracked RPZ backflow preventer (FL): $400–$1,200 installed
- Cost of foam backflow insulation bag (prevention): $15–$40
FL Backflow Annual Test Requirement: FL law requires all RPZ, PVB, and DCVA backflow preventers on irrigation systems to be tested annually by a licensed FL backflow tester. If damaged during a freeze, the device must be repaired AND retested before returning to service.
FL WMD Seasonal Watering Schedules
Each Florida Water Management District sets seasonal watering restrictions that override your controller schedule unless you have an exemption or variance.
- SFWMD (Palm Beach / Broward / Miami-Dade / Collier / Lee) — Year-round: 2 days/week max
- SFWMD — Winter (Nov–Mar) for most odd-even addresses: 1 day/week recommended
- SWFWMD (Hillsborough / Pinellas / Sarasota / Manatee) — Year-round: 2 days/week max
- SWFWMD — Modified Phase 1 restriction areas: 1 day/week
- SJRWMD (Orange / Seminole / Volusia / Brevard) — Year-round: 2 days/week max
- SRWMD (North FL / Gainesville area): 2 days/week; 1 day Nov–Mar
- NWFWMD (Panhandle — Pensacola / Panama City / Tallahassee): 2 days/week; winter varies
- All WMDs — prohibited irrigation hours: 10 AM – 4 PM daily
- All WMDs — irrigation during/after rainfall prohibited: 48 hrs after ≥0.5" rain
Smart Controller Exemption: All 5 FL WMDs offer exemptions from day/time restrictions for properties with EPA WaterSense-certified smart irrigation controllers (ET-based or soil moisture sensor-based). Get a variance from your local WMD — it's free.
FL Irrigation Spring Activation Checklist
Best performed February–March in South FL, March–April in Central FL, April in North FL.
- Inspect backflow preventer for freeze damage (FIRST STEP): Look for cracks, bulges, or displaced relief valve bonnets. Do NOT open the supply valve if you see damage — replace first.
- Slowly open main irrigation supply valve (CRITICAL): Open over 60–90 seconds to avoid water hammer.
- Check supply pressure at backflow preventer (CRITICAL): Normal FL municipal supply: 50–80 PSI. If over 80 PSI, your pressure regulator may have failed.
- Run each zone manually from controller — 2 minutes each (CRITICAL): Walk the zone and look for broken heads, geysers, missing heads, and dry zones.
- Adjust spray head arc and radius for new plant growth (IMPORTANT).
- Replace broken or missing spray heads and rotors (IMPORTANT): Use same-brand, same-precipitation-rate heads.
- Clean or replace clogged nozzles and filters (IMPORTANT): Soak clogged nozzles in white vinegar 30 minutes, rinse.
- Open and inspect each valve box (IMPORTANT): A stuck-open solenoid valve wastes thousands of gallons per day.
- Test rain sensor and freeze sensor operation (IMPORTANT): Required by FL law (FS §373.62).
- Program summer irrigation schedule — WMD compliant (CRITICAL): Irrigation must start and finish before 10 AM or begin after 4 PM.
- Check and adjust drip emitters in planting beds (RECOMMENDED): Drip emitters clog easily in FL's hard water.
- Verify pump operation (if pump-fed system) (IMPORTANT).
- Document zone runtimes and coverage for each zone (RECOMMENDED).
- Schedule annual backflow preventer test (LEGALLY REQUIRED): Cost $65–$150.
FL Summer Irrigation Runtime Guide by Grass Type
Starting runtimes for Florida's rainy season (June–September).
- St. Augustine (most common FL grass) — 15–20 min 2×/week (spray heads)
- Zoysia — 10–15 min 2×/week
- Bahia (drought-tolerant) — 10–15 min 1–2×/week
- Bermuda — 12–18 min 2×/week
- Floratam St. Augustine — winter runtime 20–25 min 1×/week (Dec–Feb South FL)
- Optimal irrigation start time (any grass, FL code): 4 AM – 9 AM
- Typical FL application rate — pop-up spray head: 1.5 in/hour; need 0.5–0.75 in/cycle
- Typical FL application rate — rotor head: 0.4–0.6 in/hour; need longer runtimes
FL Rainy Season Tip: June–September, most FL lawns need 0 supplemental irrigation during weeks with 0.5+ inches of natural rainfall. Program seasonal adjustment to 0% during June–September and use a rain sensor to skip watering after rain — this can cut water bills by $40–$100/month.
Zone-by-Zone Pressure & Flow Checker
Check each irrigation zone for correct operating pressure and expected head count. Low pressure indicates a broken pipe, missing head, or partially closed valve. High pressure indicates a failed pressure regulator.
How to measure zone pressure: Use a pressure gauge with a 3/4" hose thread adapter. Cap all heads in the zone except one, attach the gauge to the open head riser, and run the zone. Or use a pitot tube gauge at an open head. Normal FL zone operating pressure: 30–50 PSI at the head.
FL Irrigation Pressure Reference
- Minimum operating pressure — pop-up spray heads: 15–20 PSI at head
- Optimal operating pressure — pop-up spray heads: 30 PSI at head
- Maximum pressure — pop-up spray heads (fogging begins): >40 PSI — install pressure-regulating heads
- Optimal pressure — gear-drive rotors (e.g., Rain Bird 5000): 30–50 PSI at head
- Optimal pressure — MP Rotator nozzles: 40–55 PSI at head
- Optimal pressure — drip emitters: 15–25 PSI at emitter
- Typical pressure loss — 100 ft 1" PVC at 10 GPM: ~3–4 PSI
- Pressure drop indicating underground leak: >15 PSI drop vs. expected
Pressure-Regulating Heads: If your FL municipal supply exceeds 65 PSI, install pressure-regulating spray heads (e.g., Hunter Pro-Spray PRS, Rain Bird 1800-PRS). These maintain 30 PSI at the head, reducing misting, improving uniformity, and extending head life by 30–50%.
FL Sprinkler Head Precipitation Rate Guide
FL's sandy soils absorb water quickly — application rates above 0.75 in/hour on flat ground cause runoff.
- Fixed spray head — 8-ft radius, full circle: 1.4 in/hour
- Fixed spray head — 10-ft radius, full circle: 1.5 in/hour
- Fixed spray head — 12-ft radius, full circle: 1.7 in/hour
- Rain Bird 5000 rotor — 30-ft radius, full circle: 0.5 in/hour
- MP Rotator — 13-ft radius, full circle: 0.4 in/hour
- Drip emitter — 0.5 GPH per emitter: Varies by spacing
Mixed Head Type Warning: Never mix spray heads and rotors on the same zone — they have very different precipitation rates. This is a common FL irrigation error and a WMD compliance violation (runoff).
Schedule Irrigation Service
Services: Annual backflow preventer test & certification (FL code required); spring start-up inspection & zone audit; freeze damage repair (backflow preventers, PVC, heads); WMD compliance review & watering schedule setup; broken head replacement & zone repair; smart controller installation & programming; pump service & pressure testing; new system installation & FL permit.
Emergency Irrigation Service
Broken main irrigation line, flooded yard, or burst backflow preventer after a freeze? Response within 2 hours. 24/7 Emergency · Licensed & Insured · All FL Counties.