Well water treatment in St. Johns County
St. Johns County wells draw from the shallow surficial aquifer, not the deep limestone under Jacksonville, so your water needs its own numbers. We hold no county hardness data and we won't guess at it. We test at your tap in St. Augustine, Ponte Vedra and Nocatee.
ST. JOHNS COUNTY · ON PRIVATE WELLS
9,668 well households
FLWMI well and septic register, 2026-07-17 lead-list build as of 2026-07-17
Why is St. Johns County water a different story than Jacksonville's?
Because the aquifer under your house is a different aquifer. USGS work here found that the Floridan fails secondary drinking water standards and gets used mostly for irrigation. Homes draw from the shallower surficial aquifer above it. That is the opposite of Duval, where domestic wells reach down into the limestone.
Depth changes what the water picks up on the way to your tap. A shallow well and a deep limestone well in the same region can read nothing alike. Numbers borrowed from one county do not transfer to the other.
What do we know about St. Johns County well water, and what don't we?
We will start with the gap, because it is the important part. There is no hardness reading for St. Johns County in the domestic depth band. None. Which means nobody, us included, should project Duval’s numbers south across the county line.
What we do know: about 9,668 households here are on private wells, and the domestic supply is surficial rather than Floridan. So a reading at your own tap is not a nice-to-have here. It is the only honest starting point.
Do you have city water or well water here?
Two different answers live in this county, and which one applies depends on where the house sits. Well households cluster on the outlying acreage, west and south of the developed corridor, roughly 9,668 of them. The master-planned communities run on utility water, and those homeowners have a published annual report to read.
If you are on a well, you own the whole treatment train and nobody publishes your numbers for you.
What should a St. Johns County well owner test for?
Bacteria and nitrate at least once a year, and lead every three years, always at a state-certified lab. That is Florida DOH guidance for private wells. County health departments run the sampling for roughly $20 to $30 a sample, and they will tell you how to collect it.
Coliform is a bacterial culture, not a dropper test. Our in-home test reads hardness, iron, pH, TDS and chlorine at your tap; bacteria, lead and PFAS go to a certified lab we help you arrange.
Just moved into a new build?
Get a baseline number in the first month. New construction in Nocatee, World Golf Village and the newer communities means many homeowners have never had their water read. And this county has no published chemistry to fall back on.
A reading now tells you what your plumbing is starting from, and it gives you something to compare against in three years when the shower door starts to look different.
Which utility serves you, and what does it use to disinfect?
| System | Disinfectant |
|---|---|
| CR 214 Mainland | Chloramine |
| Northeast (buys from JEA’s Major Grid) | Chloramine |
| Sawgrass | Chlorine |
| Northwest | Chlorine |
| Ponte Vedra | Chlorine |
It varies by system, and the difference changes the filter. Same county, same utility name, two different disinfectants depending on your address. They are not removed the same way. Ordinary activated carbon handles free chlorine well. Chloramine is harder to remove and needs catalytic carbon. Check which system serves you before buying a filter.
Where we work in the county
- St. Augustine and the CR 214 mainland
- The mainland system on the CR 214 corridor chloraminates. So if you taste your disinfectant there, the answer is catalytic carbon, not a standard carbon block. Out past the developed edge you are on a surficial well and you need your own reading.
- Ponte Vedra
- The Ponte Vedra utility system chlorinates, which ordinary activated carbon handles well. Older properties off the utility grid are on wells.
- Nocatee and World Golf Village
- Master-planned and on utility water, with a published annual report. The common question here is a baseline reading on a brand-new build rather than a treatment problem.
Cities we serve in St. Johns County
St. Augustine
Water treatment in St. Augustine, sized to local water.
Ponte Vedra Beach
Water treatment in Ponte Vedra Beach, sized to local water.
Nocatee
Water treatment in Nocatee, sized to local water.
Answer six questions and see the one your water calls for
Serving Jacksonville
See all service areas ›Common questions about St. Johns County water
Does St. Johns County have hard water?
Nobody has published a hardness reading for St. Johns County wells in the domestic depth band, so the honest answer is that a test at your tap is the only way to know. What is documented is that homes here draw from the shallow surficial aquifer rather than the deep limestone, and that neighboring counties read very differently from each other.
Is the water in St. Augustine chlorinated or chloraminated?
It depends which system serves your address. St. Johns County Utilities chloraminates its CR 214 Mainland and Northeast systems, and chlorinates Sawgrass, Northwest and Ponte Vedra. That changes the filter you want, because chloramine needs catalytic carbon while free chlorine does not.
How often should I test a well in St. Johns County?
Bacteria and nitrate at least once a year, and lead every three years, through a state-certified laboratory. That is Florida DOH guidance. Your county health department runs the sampling program at roughly $20 to $30 per sample and will tell you how to collect it properly.