Local Water Quality
Jacksonville Well Water Treatment Guide: What Duval, Nassau & Clay County Well Owners Need to Know
Jacksonville is a city of contrasts when it comes to water. JEA — Jacksonville Electric Authority — serves most of Duval County's urban and suburban residents with treated water from the Upper Floridan Aquifer. But Jacksonville is also the largest city by land area in the contiguous United States, and that geography means tens of thousands of residents in rural Duval County, neighboring Nassau County, Clay County, and St. Johns County rely entirely on private wells for their household water supply.
If you're one of them, your water situation is entirely different from your neighbor on city water — and the challenges are more complex, more varied, and more personal. You own the aquifer connection. You're responsible for treatment. And in the Jacksonville area, there are some specific contamination concerns that make private well testing more urgent than in many other parts of Florida.
**The PFAS Problem Near Jacksonville's Military Installations**
Per- and polyfluoroalkyl substances (PFAS) — often called "forever chemicals" — are one of the most significant private well concerns in the Jacksonville metro area. The contamination traces back to aqueous film-forming foam (AFFF), a firefighting compound used extensively at military bases for decades.
Naval Air Station Jacksonville, located along the St. Johns River in Duval County, has a documented AFFF use history that has resulted in PFAS detections in the surrounding groundwater. The contamination plume has been mapped and studied, with certain residential areas near the base showing well water PFAS concentrations above EPA advisory levels.
Cecil Field — a former Naval Air Station turned commercial airport in western Duval County — is another known PFAS source. The area around Cecil Field, including parts of western Jacksonville and extending into Clay County, has documented groundwater PFAS contamination from historical military firefighting activities.
PFAS chemicals don't have an odor or taste. You cannot detect them with your senses. The only way to know if your well is contaminated is to test it. PFAS are associated with thyroid disease, certain cancers, immune system effects, and developmental issues in children — and they do not break down in the environment or the human body, hence the "forever" designation.
If you live within 2–3 miles of NAS Jacksonville or within the Cecil Field influence zone, PFAS testing should be a priority.
**The Underground Picture: What Northeast Florida Wells Tap**
Jacksonville-area private wells access one of two primary water-bearing zones:
The **surficial aquifer** — a relatively shallow, unconfined sand-and-gravel formation — is the target for many older rural wells in Duval, Nassau, and Clay counties. It's easier to drill and historically produced adequate yields, but it's highly vulnerable to surface contamination: septic systems, agricultural runoff, stormwater infiltration, and industrial activity can all impact water quality. Surficial aquifer wells in the Jacksonville area frequently show:
- Elevated iron (0.3 to 5+ mg/L) producing orange-red staining on fixtures, laundry, concrete, and irrigation systems
- Hydrogen sulfide (H2S) at 0.1 to 2 mg/L — that characteristic rotten egg odor that intensifies in hot water
- Tannins from decomposing organic matter in shallow sandy soils — a yellowish-brown color and slightly bitter taste
- Coliform bacteria presence in poorly constructed or aging well casings
- Nitrates in agricultural areas of Nassau and western Duval counties — from fertilizer application and legacy phosphate activity
The **Upper Floridan Aquifer** — the same source JEA uses for municipal supply — is accessed by deeper private wells, typically 200 to 600 feet down. These wells generally produce harder, more mineral-rich water, but are better protected from surface contamination. Floridan wells in the Jacksonville area show:
- Hardness from 3 to 22 GPG depending on district (JEA's own service area varies this widely between north Duval and the Southside)
- Lower iron but higher dissolved solids
- Occasional hydrogen sulfide — the Floridan Aquifer is anaerobic in many zones, enabling sulfur-reducing bacteria activity
- Radionuclides (radium-226 and radium-228) at low but measurable concentrations, consistent with Floridan Aquifer characteristics throughout Florida
**Getting Your Well Tested: What to Test For**
Before investing in any treatment equipment, test your water. A basic panel for Jacksonville-area wells should include:
- Total coliform and E. coli bacteria
- Nitrates (especially if near agriculture or septic systems)
- Iron and manganese
- Hydrogen sulfide (measured as total sulfide)
- pH and total hardness
- Total dissolved solids (TDS)
- Arsenic (occasionally elevated in northeast Florida Floridan wells)
If you're near a military installation or in a mapped PFAS concern zone: request a PFAS panel. The EPA's new MCLs for PFAS set limits at 4 parts per trillion (ppt) for PFOA and PFOS individually — an extremely low threshold that requires laboratory-grade analysis (not basic home test kits).
**Treatment Solutions for Jacksonville Well Water**
Once you know what's in your water, treatment options align clearly with your results:
*For hydrogen sulfide and iron:* An oxidation-filtration system is the most effective approach. Air injection oxidizers or chemical oxidation (chlorine or ozone injection) followed by a filter bed converts dissolved H2S gas and dissolved iron into filterable particles. For moderate H2S (under 2 mg/L) and iron (under 5 mg/L), a combination iron filter — often using birm, greensand, or catalytic carbon media — can handle both contaminants in a single vessel. Severely elevated H2S may require dedicated aeration before filtration.
*For tannins:* An anion exchange resin specifically designed for tannin removal addresses discoloration and the associated slightly bitter taste. Standard cation exchange water softeners do not remove tannins effectively — this requires a dedicated anion unit, typically installed after iron filtration to protect the resin bed from iron fouling.
*For hardness:* A salt-based ion exchange softener or a salt-free template-assisted crystallization (TAC) system reduces scale formation. If your Floridan well produces very hard water (over 15 GPG), a whole-house softener before your water heater and main distribution lines will dramatically extend appliance life and reduce cleaning time. TAC systems offer a salt-free alternative that transforms hardness minerals into a non-adherent crystalline form rather than exchanging them — useful where salt discharge is a concern or on septic systems.
*For bacteria:* UV disinfection is the gold standard for private well bacterial treatment. A properly sized UV system (typically 12–55 mJ/cm² dosage) mounted after filtration and softening at the point of entry provides continuous disinfection without adding chemicals. If bacterial contamination is active, shock chlorination of the well casing itself is often the first step before installing permanent UV treatment.
*For PFAS:* Reverse osmosis (RO) is the most accessible and effective treatment for PFAS removal at the point of use. A standard under-sink five-stage RO system with a high-quality membrane removes PFAS, nitrates, radionuclides, heavy metals, and the vast majority of dissolved contaminants from drinking and cooking water. Granular activated carbon (GAC) — particularly catalytic carbon — also adsorbs many PFAS compounds, though RO provides higher and more consistent removal rates. Whole-house PFAS treatment exists (large-scale GAC or membrane filtration) but is substantially more expensive than point-of-use RO.
*For nitrates:* RO is also the preferred treatment for nitrates at the point of use. Nitrates are of particular concern for infants under six months — "blue baby syndrome" — and standard carbon filters, UV, or softeners do not remove nitrates. An under-sink RO system for drinking and cooking water is the appropriate response to elevated nitrates.
**A Practical Treatment Sequence for Jacksonville Wells**
Most Jacksonville-area private well systems that need treatment benefit from a staged approach at point of entry (whole-house) combined with point-of-use drinking water treatment:
1. **Sediment pre-filter** (5–20 micron) — removes sand, silt, particulates that foul downstream equipment
2. **Oxidation/iron filtration** — addresses H2S, iron, manganese
3. **Tannin filter** (if needed, based on test results) — anion resin removes color and taste
4. **Water softener or TAC system** — addresses hardness, protects appliances and plumbing
5. **UV disinfection** — bacterial protection at point of entry, final stage before distribution
6. **Under-sink RO system** (kitchen) — addresses PFAS, nitrates, radionuclides, dissolved contaminants for drinking and cooking
This sequence gives you comprehensively treated water at every tap for whole-house purposes, with an additional layer of protection for drinking and cooking at the kitchen.
The Jacksonville area's private well challenges are real and varied — from sulfur odors in surficial aquifer wells to PFAS concerns near military installations to hardness variation across the county. Testing first, treating specifically, and verifying results puts you in control of your family's water quality rather than hoping for the best from an unmonitored source.
For residents on Jacksonville city water supplied by JEA, the utility's annual water quality report is available on the JEA website and provides a detailed breakdown of source water, treatment, and contaminant monitoring results. City water customers generally deal primarily with hardness (3–22 GPG depending on service district), chloramines, and disinfection byproducts — different concerns than private well owners, but worth addressing for those who want optimized water quality throughout the home.