The EPA recommends that private well owners test their water at least once a year for bacteria and nitrates, and more frequently for other parameters depending on local conditions. In Florida, the geology, climate, and land use patterns around most wells make this annual testing recommendation not a suggestion — it's a practical necessity.
Quality Filters And Pumps has performed well water assessments across Central Florida for over 15 years. Here's what the data actually shows about Florida well water, what parameters matter most, and what to do with your test results.
Why Florida's Geology Makes Well Testing Critical
Florida is built on limestone. The Floridan Aquifer — the source for most Central Florida private wells — is a porous limestone formation extending to depths of several thousand feet. This geology creates water quality characteristics that are different from most other regions of the country and that change over time in ways that annual testing catches early.
Limestone chemistry: Water dissolving through limestone picks up calcium and magnesium (creating hardness), bicarbonate (affecting pH), and in some zones, naturally occurring arsenic, radium, and uranium. These aren't contaminants from human activity — they're inherent to Florida's geological environment. But they affect your water quality and, at elevated levels, can be health concerns.
Karst vulnerability: Florida's limestone geology forms a karst system — a landscape with sinkholes, underground drainage channels, and direct connections between surface and groundwater. This karst connectivity means that surface events (agricultural runoff, septic system discharge, flooding) can rapidly reach groundwater through pathways that don't exist in non-karst geology. A heavy rainstorm that deposits agricultural chemicals into a sinkhole can show up in wells miles away within days.
Agricultural land use: Central Florida's patchwork of citrus, cattle, nursery operations, and vegetable farming puts agricultural chemicals within the Floridan Aquifer's recharge zones. Nitrates from fertilizer application are the most common agricultural contaminant in Florida groundwater.
What to Test For: The Complete Florida Well Water List
Bacteria (Total Coliform and E. coli) — Test Annually
The EPA's primary microbiological standard for drinking water is zero detectable coliform bacteria per 100 mL. Total coliform tests detect the broader group of fecal indicator bacteria; E. coli testing confirms fecal contamination specifically.
Why annual testing matters in Florida: The karst drainage system can rapidly introduce surface contamination into wells after flooding events (common during Central Florida's hurricane season). Septic systems — very common in rural Central Florida where municipal sewage doesn't reach — represent a potential contamination pathway that changes over time as drain fields age and soil absorption capacity changes. Well seals degrade over the 20–30 year life of a well, and aging seals can allow surface water intrusion.
If bacteria are detected: Do not drink the water untreated. Shock chlorinate the well (a disinfection treatment), then retest before returning to use. If bacteria recur after shock chlorination, investigate the contamination source — it may be structural (well seal failure) or external (nearby septic influence). A UV disinfection system provides continuous bacterial protection.
Nitrates — Test Annually
The EPA MCL for nitrate is 10 mg/L (as nitrogen). Above this level, nitrates pose a specific health risk to infants under 6 months: nitrates interfere with the oxygen-carrying capacity of hemoglobin, potentially causing "blue baby syndrome" (methemoglobinemia). Adults and older children tolerate higher nitrate levels without acute effects, but long-term exposure above health guidelines is associated with increased cancer risk.
Nitrate sources in Central Florida wells include agricultural fertilizers, septic system discharge, and animal waste from livestock operations. Nitrate concentrations can change seasonally (higher after fertilizer application and heavy rain events) and trend upward over years as land use in the recharge zone intensifies.
pH — Test Annually
The EPA's secondary standard for pH is 6.5–8.5. This range isn't primarily about health — it's about protecting your plumbing. Low-pH (acidic) water corrodes copper pipes, brass fittings, and hot water tanks, leaching lead and copper into the water supply. In older homes with copper plumbing, low-pH well water is a significant lead and copper exposure risk. High-pH (alkaline) water doesn't cause corrosion but can contribute to scale formation at a faster rate.
Florida well water pH varies considerably by location and aquifer depth. Some Floridan Aquifer zones produce naturally alkaline water (pH 7.5–8.5) due to the carbonate chemistry. Others, particularly shallower zones, can be mildly acidic.
Total Hardness — Test at Installation, Then Every 2-3 Years
Measured in grains per gallon (GPG) or mg/L as calcium carbonate. Florida well water hardness ranges from moderate (8–12 GPG) to severe (30–50+ GPG) depending on aquifer depth, location, and local geology. Hardness doesn't affect health directly, but it's the parameter that determines how quickly scale builds up in your plumbing, water heater, and appliances.
Knowing your hardness level is essential for: sizing a water softener correctly, setting softener regeneration frequency, assessing whether scale is likely contributing to appliance problems, and understanding why your soap doesn't lather well.
Iron and Manganese — Test Annually if Staining Is Present
Iron and manganese are the most common aesthetic complaints from Florida well owners. The EPA secondary standards (aesthetic, not health-based) are 0.3 mg/L for iron and 0.05 mg/L for manganese. At these levels, staining occurs. Many Florida wells test at 2–15 mg/L iron — far above the staining threshold.
Iron in Florida wells exists in two forms: ferrous (dissolved, clear water that stains on contact with air) and ferric (particulate, already oxidized, producing visibly colored water). Treatment differs by form. Testing that specifies ferrous vs. total iron helps identify the right treatment approach.
Manganese at the EPA secondary standard (0.05 mg/L) causes black staining. At the EPA health advisory level of 0.1 mg/L, manganese poses potential neurological development concerns for infants. Florida's Floridan Aquifer delivers elevated manganese in some zones.
Hydrogen Sulfide — Test if Odor Is Present
The rotten-egg smell from some Florida wells is hydrogen sulfide (H₂S) produced by sulfate-reducing bacteria in the anaerobic aquifer environment. It's detectable at extremely low concentrations (as low as 0.0005 mg/L), and at concentrations found in residential wells, it's an aesthetic problem — not typically a health hazard. But it's corrosive to metal plumbing and pump components.
Field testing with colorimetric test kits provides rapid results. Laboratory testing provides more precise quantification for treatment system sizing.
Arsenic — Test at Installation, Then Every 3 Years
Arsenic occurs naturally in the Floridan Aquifer from the dissolution of arsenic-bearing minerals in the limestone. The EPA MCL is 10 µg/L; the EWG health guideline is 0.004 µg/L — reflecting arsenic's carcinogenic nature at any detectable level. Florida's Department of Health recommends arsenic testing for all Floridan Aquifer wells.
Arsenic at levels above the EPA MCL is rare in properly drilled Central Florida wells, but levels between the EPA MCL and EWG guideline are more common than many homeowners realize. Reverse osmosis is the most effective home treatment for arsenic reduction (>95% removal).
Total Dissolved Solids (TDS) — Test at Installation and After Treatment Changes
TDS is a general indicator of the total mineral content of your water. The EPA secondary standard is 500 mg/L; levels above this affect taste noticeably. Florida well water TDS varies widely — from 200 mg/L in some zones to 800+ mg/L in others, particularly in coastal areas where saltwater intrusion is a factor. TDS measurement helps interpret other test results and assess overall water mineral load.
PFAS — Test at Installation, Repeat Every 3 Years
PFAS ("forever chemicals") are emerging contaminants that have been detected in groundwater across Central Florida, particularly near military installations, airports, and areas where PFAS-containing agricultural products were applied. The EPA's 2024 PFAS National Primary Drinking Water Rule sets MCLs for PFOA and PFOS at 4 parts per trillion — the strictest drinking water standard ever established.
PFAS testing requires specialized laboratory analysis and cannot be done with standard field test kits. If your well is located within a few miles of a military base, airport, or agricultural area with intensive operations, PFAS testing is strongly recommended. Reverse osmosis provides >95% PFAS reduction for positive results.
How to Interpret Your Test Results
Your laboratory results will show measured values with reference to either EPA MCLs (regulatory limits) or EPA secondary standards (aesthetic). Here's the framework for interpreting what matters:
Any bacteria detection: Immediate action required. Do not drink unboiled or untreated water. Contact a licensed well contractor for shock chlorination and follow-up testing.
Nitrate above 10 mg/L: Do not use for infant formula or as drinking water for infants. Investigate sources, consider treatment, and retest. Reverse osmosis is effective for nitrate removal.
pH below 6.5: Acidic water is corroding your plumbing. Neutralizing filtration (calcite or magnesium oxide media) raises pH to protective levels.
Iron above 0.3 mg/L: Treatment recommended. Type of treatment depends on concentration and form (ferrous vs. ferric).
Hardness above 7 GPG: Softening recommended for appliance protection. Above 15 GPG, softening is strongly recommended. Above 25 GPG, softening is essential.
Arsenic above EPA MCL (10 µg/L): Treatment required. Reverse osmosis is the most effective solution.
PFAS above 4 ppt for PFOA or PFOS: Treatment required. Reverse osmosis is the certified solution.
Getting Your Well Water Tested in Central Florida
Quality Filters And Pumps provides professional well water testing using certified laboratory analysis — not field test kit estimates. Our testing panels cover the parameters relevant to Central Florida's Floridan Aquifer geology, and we walk through your results with you to explain what they mean and what, if anything, needs to be done.
We've been testing and treating well water across Marion, Alachua, Orange, Lake, Citrus, and surrounding counties for over 15 years. Founded by Chase Norris with a licensed Florida well contractor license, we combine water testing expertise with the treatment and drilling knowledge to address whatever your test results reveal.
Call (352) 268-9048 or contact us online to schedule your well water test.