Tap & Air

Private wells

Florida well water: who's on a well and what to test for

An estimated 2,017,100 people in 887,400 homes, about 9.0% of Florida homes, below the national 14.6%. Estimates are from EPA's Water Source 2020 model.

People on private wells

2,017,100

Homes on wells

9.0%

Est. above arsenic limit

50,900

Alachua County: about 16% of homes on private wellsBaker County: about 58% of homes on private wellsBay County: about 12% of homes on private wellsBradford County: about 58% of homes on private wellsBrevard County: about 16% of homes on private wellsBroward County: about 1% of homes on private wellsCalhoun County: about 72% of homes on private wellsCharlotte County: about 1% of homes on private wellsCitrus County: about 35% of homes on private wellsClay County: about 33% of homes on private wellsCollier County: about 5% of homes on private wellsColumbia County: about 43% of homes on private wellsDeSoto County: about 40% of homes on private wellsDixie County: about 54% of homes on private wellsDuval County: about 17% of homes on private wellsEscambia County: about 3% of homes on private wellsFlagler County: about 8% of homes on private wellsFranklin County: about 17% of homes on private wellsGadsden County: about 43% of homes on private wellsGilchrist County: about 60% of homes on private wellsGlades County: about 28% of homes on private wellsGulf County: about 35% of homes on private wellsHamilton County: about 47% of homes on private wellsHardee County: about 41% of homes on private wellsHendry County: about 32% of homes on private wellsHernando County: about 11% of homes on private wellsHighlands County: about 16% of homes on private wellsHillsborough County: about 5% of homes on private wellsHolmes County: about 76% of homes on private wellsIndian River County: about 20% of homes on private wellsJackson County: about 68% of homes on private wellsJefferson County: about 72% of homes on private wellsLafayette County: about 68% of homes on private wellsLake County: about 17% of homes on private wellsLee County: about 3% of homes on private wellsLeon County: about 11% of homes on private wellsLevy County: about 51% of homes on private wellsLiberty County: about 69% of homes on private wellsMadison County: about 56% of homes on private wellsManatee County: about 1% of homes on private wellsMarion County: about 36% of homes on private wellsMartin County: about 6% of homes on private wellsMiami-Dade County: about 2% of homes on private wellsMonroe County: about 86% of homes on private wellsNassau County: about 38% of homes on private wellsOkaloosa County: about 6% of homes on private wellsOkeechobee County: about 30% of homes on private wellsOrange County: about 4% of homes on private wellsOsceola County: about 3% of homes on private wellsPalm Beach County: about 1% of homes on private wellsPasco County: about 10% of homes on private wellsPinellas County: about 0% of homes on private wellsPolk County: about 6% of homes on private wellsPutnam County: about 68% of homes on private wellsSt. Johns County: about 16% of homes on private wellsSt. Lucie County: about 3% of homes on private wellsSanta Rosa County: about 10% of homes on private wellsSarasota County: about 3% of homes on private wellsSeminole County: about 10% of homes on private wellsSumter County: about 11% of homes on private wellsSuwannee County: about 57% of homes on private wellsTaylor County: about 45% of homes on private wellsUnion County: about 55% of homes on private wellsVolusia County: about 15% of homes on private wellsWakulla County: about 48% of homes on private wellsWalton County: about 21% of homes on private wellsWashington County: about 70% of homes on private wells
Homes on private wellsUnder 5%5-15%15-30%30-50%50% or more

Every Florida county

Sorted by people on private wells. Arsenic and nitrate are modeled for typical wells in the county, not measured at yours; depth is the median of domestic well records.

Duval County177,70017%1.8%0.0n/a
Marion County137,50036%1.0%1.390 ft
Brevard County102,10016%1.7%0.0n/a
Volusia County88,40015%1.4%0.0n/a
Hillsborough County81,9005%1.5%0.0100 ft
Monroe County69,10086%4.4%0.0n/a
Lake County68,90017%1.3%0.1n/a
Clay County67,20033%1.8%0.0n/a
Pasco County61,60010%2.4%0.1n/a
Orange County56,8004%1.3%0.0n/a
Citrus County56,30035%2.5%0.1n/a
Seminole County50,40010%1.2%0.1n/a
Polk County50,2006%1.2%0.1n/a
Putnam County49,00068%1.6%0.0n/a
Miami-Dade County46,0002%2.8%0.8n/a
Alachua County43,90016%1.1%0.5112 ft
St. Johns County41,20016%1.5%0.0n/a
Nassau County37,70038%1.8%0.0n/a
Indian River County34,20020%1.8%0.0n/a
Leon County33,90011%2.2%0.3170 ft
Jackson County29,80068%0.8%1.7140 ft
Columbia County29,70043%1.2%0.3120 ft
Bay County29,40012%4.0%0.0200 ft
Collier County27,4005%2.2%0.0n/a
Lee County26,3003%1.5%0.0n/a
Walton County25,60021%2.6%0.1260 ft
Suwannee County25,10057%1.6%1.0120 ft
Sumter County24,70011%2.1%0.2n/a
Palm Beach County23,5001%1.4%0.0n/a
Levy County22,30051%1.2%0.469 ft
Hernando County21,30011%3.3%0.0125 ft
Santa Rosa County19,80010%1.7%0.8125 ft
Gadsden County18,30043%1.6%0.0340 ft
Sarasota County18,2003%1.8%0.0n/a
Highlands County17,40016%1.4%0.1n/a
Washington County16,10070%1.9%0.2200 ft
Bradford County15,40058%1.3%0.0120 ft
DeSoto County15,30040%2.3%0.0n/a
Wakulla County15,00048%2.2%0.197 ft
Baker County14,80058%1.4%0.0180 ft
Holmes County13,50076%1.4%0.1240 ft
Okaloosa County13,5006%2.1%0.2280 ft
Okeechobee County13,10030%1.1%0.0n/a
Osceola County12,9003%1.3%0.0n/a
Martin County12,9006%2.1%0.0n/a
Broward County12,1001%1.9%0.0n/a
Hendry County12,00032%3.2%0.0n/a
Jefferson County10,80072%1.4%0.2200 ft
St. Lucie County10,1003%1.3%0.0n/a
Gilchrist County10,00060%1.2%1.085 ft
Hardee County9,90041%1.3%0.0n/a
Calhoun County9,70072%2.3%0.1160 ft
Madison County9,30056%1.5%0.3120 ft
Taylor County9,30045%1.6%0.044 ft
Escambia County8,9003%2.6%0.8120 ft
Flagler County8,4008%1.4%0.0n/a
Dixie County8,40054%1.3%0.157 ft
Manatee County6,9001%1.8%0.0n/a
Union County6,80055%1.3%0.0140 ft
Hamilton County5,50047%1.6%0.2150 ft
Gulf County5,20035%1.6%0.0180 ft
Lafayette County4,50068%1.7%0.377 ft
Liberty County4,20069%2.5%0.0200 ft
Glades County4,10028%2.5%0.0n/a
Charlotte County3,2001%3.1%0.0n/a
Franklin County2,40017%2.3%0.0100 ft
Pinellas County2800%2.8%0.0100 ft

Shading: red is among the highest counties nationally, amber the middle, green the lower range. Click a column to sort.

Most well users above the arsenic limit

Test first, then treat what the test finds

We may earn a commission from links below, at no cost to you. Picks follow the testing order, not who pays. How we make money.

1. Certified lab well test

Start here, every year

A mail-in kit analyzed by a certified lab measures bacteria, nitrate, arsenic, metals and more. Test strips cannot measure arsenic or uranium reliably.

Mail-in certified lab well water test$$

2. Sediment pre-filter

Sand, silt or cloudy water

A 5-micron cartridge after the pressure tank catches sand, silt and rust before they reach fixtures or other filters. Cartridges are cheap and swap every few months.

5-micron whole-house sediment filter$

3. Iron and sulfur filter

Orange stains or rotten-egg smell

Air-injection or oxidizing-media filters remove orange staining and rotten-egg smell. Size one from a lab result for iron, manganese and hydrogen sulfide.

Air-injection iron and sulfur filter$$$

4. UV disinfection system

Coliform bacteria in a test

Inactivates bacteria and viruses; usually for private wells or after boil notices.

12 GPM whole-house UV purifier$$$

5. Under-sink reverse osmosis

Arsenic, nitrate or uranium in a test

The most thorough option for drinking water: PFAS, lead, nitrate, arsenic and more. Look for NSF/ANSI 58.

Waterdrop G3P600 tankless RO$$$ iSpring RCC7AK reverse osmosis$$

6. Whole-house well filter

Several problems at once

Multi-stage sediment and carbon for every tap. Add UV if bacteria shows up, and choose stages from your lab results, not a guess.

Waterdrop WHF21 2-stage whole-house filter$$
Get free well water treatment quotes

Questions

Which Florida counties rely most on wells?+

By share of homes: Monroe County (86%), Holmes County (76%), Calhoun County (72%), Jefferson County (72%), Washington County (70%). By number of people: Duval County (177,700), Marion County (137,500), Brevard County (102,100).

Is arsenic a problem in Florida wells?+

USGS estimates about 50,900 Florida well users have water above the 10 microgram per liter arsenic limit that applies to public systems, the largest numbers in Palm Beach County, Osceola County, Lee County. Arsenic has no taste or smell, so only a lab test finds it.

Do I have to test my well when I sell a house in Florida?+

We could not confirm a statewide rule for Florida. Check with your county health department. Buyers can still make a lab test a condition of the offer.

How often should I test my well?+

No federal law covers private wells. EPA's drinking water limits apply to public water systems, so testing and treating a private well is up to the owner. EPA and CDC recommend testing at least once a year for coliform bacteria, nitrate, pH and total dissolved solids, and testing for arsenic, uranium, radon and other local concerns based on where you live.

Well-user counts, arsenic and nitrate figures are each a modeled estimate built from national datasets, not a count of tested wells, and well depths summarize drilling records rather than every well. Your own well can be very different from the county average, which is why the only answer for your home is a lab test. Sources: EPA Office of Research and Development, Water Source 2020 (private well estimates by census block); CDC Environmental Public Health Tracking, Well Water Index (from USGS nitrate and arsenic models); USGS, county-level domestic well population with arsenic above 10 micrograms per liter (Ayotte and others, 2017); USGS Synthesized Domestic Well Database for the Conterminous United States (SynDWell-US), McCarthy and others, 2025 (depth, where a county has 30+ usable records).