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Last reviewed 2026-10-16

Marion County Well Water Testing

Marion County leans on private wells more than any other county on this site: USGS estimates that 141,161 residents, 41.1% of the county, supplied their own household water in 2015. Most of those wells tap the Upper Floridan aquifer, which lies at or near the land surface across much of the Silver Springs basin.

That shallow, porous limestone is why nitrate is the first test to order around Ocala. A USGS survey of 56 wells in the springs' recharge area found nitrate-nitrogen from below detection up to 12 mg/L, and the top of that range is above EPA's drinking-water limit.

Permits

Step 1: Order a bacteria and nitrate test, the pair Florida DOH recommends every year. Its private-well guidance says county health departments usually charge $20 to $30 per sample, plus $30 to $40 if staff visit to collect it.

Step 2: Ask DOH-Marion Environmental Public Health (352-622-7744) which kit to use and where to drop it off. The state's Bureau of Public Health Laboratories lists its bacteria test at $40 for private customers and $17 when a county health department submits the sample.

Step 3: For a first test, add hardness, iron and lead through a NELAP-certified lab; Florida DOH suggests lead every three years.

Step 4: Well work is permitted locally. In the Southwest Florida Water Management District part of the county, DOH-Marion issues well construction, repair and abandonment permits under a delegation agreement running June 1, 2026 to May 31, 2031; any new or higher fee needs adoption by the Board of County Commissioners. Where SWFWMD issues directly, Rule 40D-1.607 sets a $50 fee for a standard private well.

Step 5: The St. Johns River Water Management District covers the rest of the county. Wherever you are, Rule 62-6.005, F.A.C. keeps septic systems 75 feet from a private drinking-water well, a distance worth checking before you blame a nitrate result on fertilizer.

Local conditions

Nitrate depends on land use. The same USGS study (SIR 2004-5144) reported median nitrate-nitrogen of 1.7 mg/L under agricultural land, 1.15 under urban land and 0.09 under rangeland and forest, so horse-farm and pasture areas north and west of Ocala deserve a test every year.

Florida DOH private-well samples near Lake Weir, south of Silver Springs, ran higher. FDEP's 2012 Silver Springs TMDL report counted 234 DOH nitrate samples in the springs' capture zone after 2001, averaging 3 mg/L with a maximum of 31 mg/L.

The Floridan limestone also makes the water hard. Our tally of Water Quality Portal records (USGS data, latest sample per well) gives a median hardness of 157.5 mg/L as calcium carbonate across 58 Marion wells sampled from 2001 to 2015, and 25 of those wells were above the 180 mg/L line USGS calls very hard.

Iron is less common here than in Pasco County: in the same Water Quality Portal tally, 23 of 156 sampled wells had iron above EPA's 0.3 mg/L secondary limit.

What drives local prices

Nitrate treatment: HomeGuide's published range is $300-$5,000, from an under-sink reverse osmosis unit ($300-$950 in its RO guide) to whole-house anion exchange.
Hardness: a softener runs $1,200-$3,800 installed per HomeGuide, sized from your lab hardness in grains per gallon.
Whole-house versus one tap: on Marion's typical well, nitrate is a drinking-water issue and hardness a whole-house one, so many homes buy both a softener and a kitchen RO unit.
Annual retesting at the county's typical $20-$30 per sample is part of the cost of owning nitrate treatment.

Common jobs

Under-sink reverse osmosis for nitrate at the kitchen tap
Water softener for very hard Floridan water
Whole-house anion exchange where nitrate is high
Sediment prefilter after well repairs
Shock chlorination and retest after a positive coliform result

Service area

Private wells cover most of the county outside Ocala's water service: horse country along US 27 and SR 326, the Dunnellon area on SR 40 west, Belleview and Summerfield along US 441 and US 301, and Marion Oaks off I-75.

East of Silver Springs, homes along SR 40 toward the Ocala National Forest are nearly all on wells.

Communities: Ocala, Belleview, Dunnellon, Silver Springs Shores, Marion Oaks, Summerfield, Fort McCoy, Citra, Reddick, McIntosh, Weirsdale, Rainbow Lakes Estates

If it is an emergency

A nitrate result above EPA's limit matters most for infants: switch formula and drinking water to a safe source and call DOH-Marion Environmental Public Health for guidance, then get written quotes from independent local treatment pros.

Questions about Marion County

Is nitrate a problem in Marion County wells?

In parts of the county. FDEP's Silver Springs report counted 234 DOH private-well nitrate samples near the springs averaging 3 mg/L, and the highest reached 31 mg/L, above EPA's limit.

How much does a well test cost in Marion County?

Florida DOH says county health departments usually charge $20 to $30 per sample for bacteria or nitrate, plus $30 to $40 for a staff visit. Certified private labs set their own prices.

How hard is Marion County well water?

Our Water Quality Portal tally shows a median of 157.5 mg/L as calcium carbonate across 58 sampled wells, about 9 grains per gallon, and 25 of those wells were very hard by the USGS scale.

Who permits well repairs in Marion County?

DOH-Marion in the Southwest Florida district part of the county, under a 2026-2031 agreement; the St. Johns River district handles the rest.

Does Florida require a well test when I sell my house?

No. Florida DOH notes there is no state requirement at sale, though it recommends testing for coliform bacteria, nitrate and lead before you buy.

Sources

Nearby counties

Florida well water hub

Fees and rules change; confirm with the county office before you order. Compare installed prices in the treatment system cost guide, or run the treatment selector with your lab results.