💧 FL Well Pump &
Pressure System Guide

Troubleshoot your Florida well pump, size your pressure system, and understand your aquifer

FL Aquifer Guide · Pressure Sizing · 67 Counties
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⚡ Emergency — No Water: Check These First

1. Check circuit breaker (well pump breaker is typically 2-pole 20A or 30A — look for tripped breaker). 2. Check pressure switch: bang on it lightly with palm — contacts can stick. 3. Verify power at pressure switch with a voltage tester (both LINE terminals should show 240V). 4. Check pump start relay and capacitor (common failure point). If breaker is not tripped and switch shows voltage but pump won't start, call a licensed FL well pump contractor — do not attempt to bypass a pump that trips its breaker repeatedly.

🚨 Symptom Diagnosis Guide
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Pump Runs Continuously — Never Reaches Cutoff Pressure
Possible causes: (A) Blown well foot valve — water drains back to aquifer between pump cycles; pump can't build pressure. (B) Pump worn — impellers eroded, producing insufficient flow to build system pressure. (C) Air leak on suction side (jet pump only) — air enters suction line, preventing pump prime. (D) Undersized pump for current demand. (E) Clogged pump screen — restricted intake. Run time exceeding 30 minutes continuous without reaching cutoff pressure indicates serious system failure — turn off pump to prevent motor burnout (pump motor requires water flow for cooling).
📞 Requires service call — motor overheating risk
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Pump Cycles On/Off Rapidly (Short Cycling)
Primary cause: Waterlogged pressure tank — the internal bladder or diaphragm has failed, allowing water to completely fill the tank with no air cushion. Without air cushion, pressure swings from cutout to cut-in on every cup of water drawn — pump can cycle 5–50x per hour. Short cycling is pump-killing: the motor starts and draws 3–6x running amperage on every start. A pump cycling faster than every 1–2 minutes is at risk of motor failure from start overload. Check tank pre-charge pressure (empty system air valve at top of tank — should show 2 PSI below cut-in pressure). No air = waterlogged. Pre-charge 36–38 PSI for 40/60 system or 28 PSI for 30/50 system.
✅ DIY fix: Replace pressure tank $200–$600 + labor
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Low Water Pressure at Fixtures
Causes to check in order: (1) Verify pressure switch settings — cut-in/cutout should be 30/50, 40/60, or 50/70 PSI. (2) Check pressure gauge accuracy (gauges drift over time — replace if suspect). (3) Inspect bladder tank pre-charge. (4) Check for clogged sediment filter if installed. (5) Partially closed gate valve. (6) Iron bacteria biofilm in pipes reducing ID (FL high-iron water issue). If pump runs normally but pressure is consistently low, consider pressure switch adjustment — most switches have adjustable differential and range nuts (turn clockwise to increase pressure, 1 revolution ≈ 2–3 PSI). Document changes — never set cutout above 75 PSI without confirming system pressure rating.
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Brown / Rust-Colored Water at Tap
FL-specific issue: Nearly all FL aquifers contain elevated dissolved iron (0.5–8.0 mg/L typical in Floridan Aquifer System). Brown water after pump disturbance or on first draw: (A) Iron bacteria in well — iron-oxidizing bacteria form gelatinous deposits that can enter supply on pump startup. (B) Disturbed sediment in well casing from pump change or pump drop. (C) Corroding galvanized piping downstream of pump. (D) Rotten egg smell + brown water = iron sulfide + sulfur bacteria. Well shock chlorination (1-2 pints of household bleach per 100 gallons of well water) treats bacterial contamination. Persistent iron requires an iron filter system (oxidizing filter, air injection, or greensand filter) sized for FL's iron levels.
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Rotten Egg Smell (Hydrogen Sulfide)
Hydrogen sulfide (H₂S) in well water is extremely common in FL — particularly in the Floridan Aquifer System where ancient organic matter produces H₂S naturally. NOT a health emergency at low levels but taste/odor nuisance. Measurement: FL DEP reports H₂S in many county well water samples at 0.1–2.0 mg/L (detectable at 0.5 ppb by smell). Solutions: (1) Aeration system (air stripping tank) — most effective for H₂S, converts to sulfate, no chemicals. (2) Chlorination injection system. (3) Activated carbon filter (for low-level H₂S under 1 mg/L). Well chlorination can temporarily reduce H₂S if sulfur bacteria are the source — have water tested to determine if biological or geologic origin.
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Air Spurting from Faucets (Air in Lines)
Air in water lines from a well system typically indicates: (1) Well is drawing air — water table dropped below pump intake (common in FL drought conditions or after wet season overuse). (2) Loose or cracked suction pipe joint (jet pump) allowing air entry under vacuum. (3) Vented casing with air pocket. (4) Failing foot valve allowing partial drain-back with air ingestion on restart. Monitor water level trend — FL aquifer levels fluctuate seasonally. If problem begins in dry season (Oct–May) and resolves in wet season, well depth or pump placement may need adjustment.
Pressure Switch Settings Reference

FL standard residential pressure settings — all require minimum 20 PSI differential between cut-in and cutout:

30/50 PSI
Low demand / 1BR
40/60 PSI
Standard / 2–4BR
50/70 PSI
High demand / irrigation

⚠️ Do not exceed 75 PSI cutout on residential systems — exceeds most fixture pressure ratings. Standard FL residential pipe pressure rating: 160 PSI (PVC Schedule 40), but pressure relief valve should be set at 75 PSI for safety.

Well Pump Sizing Calculator
Pump Type Comparison — FL Applications
Pump TypeMax DepthBest ForFL Note
Shallow Jet25 ftShallow aquiferN Central FL only
Deep Jet75–100 ftIntermediate wellsDual-pipe required
Submersible 4"25–400 ftMost FL homesMost common FL type
Submersible 6"100–600 ftHigh yield / artesianSouth FL artesian
Variable Speed25–400 ftConstant pressureBest for irrigation
Pressure Tank Sizing (Drawdown Volume)

FL rule of thumb: tank drawdown capacity should equal 1 gallon per GPM of pump flow rate, minimum. Undersized tanks cause short cycling. Oversized tanks never hurt — buy larger when in doubt.

Pump GPMMin Tank (gal)Recommend (gal)30/50 Pre-Charge
5 GPM14 gal20 gal28 PSI
7 GPM20 gal30–32 gal28 PSI
10 GPM30 gal44–60 gal38 PSI for 40/60
15 GPM44 gal86 gal48 PSI for 50/70
20 GPM60 gal119 gal48 PSI for 50/70
Florida Aquifer System Overview
🌊Floridan Aquifer System: The primary drinking water source for Central and North Florida — one of the most productive aquifer systems in the world, spanning 100,000 sq mi. Karst limestone formation, naturally artesian in many areas (wells flow without pumping). Depth: 100–1,000+ ft below land surface in North/Central FL; deeper and more pressurized in South FL. Excellent water quality in most areas — naturally filtered through limestone. High in calcium, magnesium, and sometimes iron and hydrogen sulfide.
🏖️Surficial Aquifer System: Shallow unconfined aquifer present throughout FL, ranging from 10–150 ft depth. Used for lawn irrigation throughout FL (not typically drinking water — vulnerable to surface contamination). Sandy formation — lower yield than Floridan. Very common source for irrigation well systems in South FL. Susceptible to saltwater intrusion in coastal areas.
💎Intermediate Aquifer System: Found primarily in Southwest FL (Charlotte, Lee, Collier, Sarasota counties). Between Surficial and Floridan Aquifers. Varying water quality — may have elevated chlorides in coastal areas. Used for residential wells in areas where Floridan is too deep or brackish.
⚠️Saltwater Intrusion: Critical issue for SE and SW coastal FL — excessive pumping has allowed saltwater to migrate inland in Miami-Dade, Broward, Lee, and Collier counties. Well water in coastal areas should be tested for chlorides (above 250 mg/L is undrinkable). FL SFWMD monitors saltwater intrusion front lines — some coastal properties have permanently lost usable well water access.
FL Well Depth by County — Select Region
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