FL Well Pump & Pressure System Guide
Troubleshoot your Florida well pump, size your pressure system, and understand your aquifer.
Emergency — No Water: Check These First
- 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 bypass a pump that trips its breaker repeatedly.
Symptom Diagnosis Guide
Pump Runs Continuously — Never Reaches Cutoff Pressure: (A) Blown well foot valve — water drains back to aquifer between cycles. (B) Pump worn — impellers eroded. (C) Air leak on suction side (jet pump). (D) Undersized pump. (E) Clogged pump screen. Run time exceeding 30 minutes continuous without reaching cutoff indicates serious failure — turn off pump to prevent motor burnout (motor requires water flow for cooling).
Pump Cycles On/Off Rapidly (Short Cycling): Primary cause is a waterlogged pressure tank — bladder/diaphragm failed, water fills tank with no air cushion; pump can cycle 5–50x per hour. The motor draws 3–6x running amperage on every start. A pump cycling faster than every 1–2 minutes risks motor failure. Check tank pre-charge (air valve at top should show 2 PSI below cut-in). Pre-charge 36–38 PSI for 40/60 system or 28 PSI for 30/50. DIY fix: replace pressure tank $200–$600 + labor.
Low Water Pressure at Fixtures: Check in order: (1) pressure switch settings (30/50, 40/60, or 50/70 PSI); (2) pressure gauge accuracy; (3) bladder tank pre-charge; (4) clogged sediment filter; (5) partially closed gate valve; (6) iron bacteria biofilm reducing pipe ID (FL high-iron issue). Most switches have adjustable nuts (clockwise to increase, 1 rev ≈ 2–3 PSI). Never set cutout above 75 PSI.
Brown / Rust-Colored Water at Tap: FL aquifers contain elevated dissolved iron (0.5–8.0 mg/L typical in Floridan). Causes: (A) iron bacteria forming gelatinous deposits; (B) disturbed sediment from pump work; (C) corroding galvanized piping; (D) rotten egg + brown = iron sulfide + sulfur bacteria. Shock chlorination (1–2 pints household bleach per 100 gallons well water) treats bacterial contamination. Persistent iron needs an iron filter (oxidizing, air injection, or greensand).
Rotten Egg Smell (Hydrogen Sulfide): Extremely common in FL, particularly Floridan Aquifer where ancient organic matter produces H₂S. Not a health emergency at low levels. FL DEP reports H₂S at 0.1–2.0 mg/L in many county samples. Solutions: (1) aeration system (most effective, no chemicals); (2) chlorination injection; (3) activated carbon (for under 1 mg/L). Test to determine biological vs. geologic origin.
Air Spurting from Faucets (Air in Lines): (1) well drawing air — water table dropped below pump intake (FL drought/overuse); (2) loose/cracked suction pipe (jet pump); (3) vented casing air pocket; (4) failing foot valve. Monitor water level trend — FL aquifer levels fluctuate seasonally; if it begins dry season and resolves wet season, pump placement may need adjustment.
Pressure Switch Settings Reference
FL standard residential settings, all requiring minimum 20 PSI differential: 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. Standard FL residential pipe rating: 160 PSI (PVC Sch 40), but pressure relief valve should be set at 75 PSI for safety.
Pump Type Comparison — FL Applications
| Pump Type | Max Depth | Best For | FL Note |
|---|---|---|---|
| Shallow Jet | 25 ft | Shallow aquifer | N Central FL only |
| Deep Jet | 75–100 ft | Intermediate wells | Dual-pipe required |
| Submersible 4" | 25–400 ft | Most FL homes | Most common FL type |
| Submersible 6" | 100–600 ft | High yield / artesian | South FL artesian |
| Variable Speed | 25–400 ft | Constant pressure | Best 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 never hurt.
| Pump GPM | Min Tank (gal) | Recommend (gal) | 30/50 Pre-Charge |
|---|---|---|---|
| 5 GPM | 14 gal | 20 gal | 28 PSI |
| 7 GPM | 20 gal | 30–32 gal | 28 PSI |
| 10 GPM | 30 gal | 44–60 gal | 38 PSI for 40/60 |
| 15 GPM | 44 gal | 86 gal | 48 PSI for 50/70 |
| 20 GPM | 60 gal | 119 gal | 48 PSI for 50/70 |
Florida Aquifer System Overview
Floridan Aquifer System: Primary drinking water source for Central and North Florida — one of the most productive aquifers in the world (100,000 sq mi). Karst limestone, naturally artesian in many areas. Depth 100–1,000+ ft in North/Central FL; deeper and more pressurized in South FL. Excellent quality in most areas; high in calcium, magnesium, sometimes iron and hydrogen sulfide.
Surficial Aquifer System: Shallow unconfined aquifer throughout FL, 10–150 ft depth. Used for lawn irrigation (not typically drinking water — vulnerable to surface contamination). Sandy, lower yield. Very common irrigation source in South FL; susceptible to saltwater intrusion in coastal areas.
Intermediate Aquifer System: Primarily Southwest FL (Charlotte, Lee, Collier, Sarasota). Between Surficial and Floridan; may have elevated chlorides in coastal areas.
Saltwater Intrusion: Critical for SE and SW coastal FL — excessive pumping allowed saltwater migration inland in Miami-Dade, Broward, Lee, Collier. Coastal well water should be tested for chlorides (above 250 mg/L is undrinkable). Some coastal properties have permanently lost usable well water access.