Florida
Home › State by State › Florida

Florida water profile

Nitrate in Florida community water systems

Most Florida community water systems report nitrate below 3 mg/L, but the systems that run higher gather in one place: the karst springs region of the central peninsula, where the Floridan aquifer lies open to the surface. See where the pattern concentrates and what each reporting system measured in the three years from August 9, 2023 to August 9, 2026.

Browse all 1,509 Florida systems →

Search by the utility or system name shown on a water bill. Example: Gainesville Regional Utilities. Private wells are not in this inventory.

95%
of the state’s 1,591 active community water systems have a current result here
1,509
systems with a current nitrate result
21,548,640
people served by those reporting systems
2.3%
of reporting systems at or above 5 mg/L
How to read these numbers Each system is placed into a band by its most recent reported result within a rolling three-year window. The bands describe how strongly human activity, read from nitrate, has marked a water source; they are not a safety verdict. Figures describe system reporting, not nitrate measured at an individual tap.

How Florida's systems fall across the five bands

Most systems report below 3 mg/L

Natural background
0.00–0.99 mg/L as N
1,205 systems · 19,626,062 served
Human impact likely
1.00–2.99 mg/L as N
213 systems · 1,551,052 served
Human impact clear
3.00–4.99 mg/L as N
57 systems · 234,557 served
Health-study range
5.00–9.99 mg/L as N
32 systems · 75,852 served
Above the federal limit
10.00 mg/L and above
2 systems · 61,117 served

Each system appears in one band only, placed by its most recent reported result in the current three-year window. Counts sit beside people served so a small number of larger systems cannot hide behind a row of tiny ones. Of the 34 systems reporting 5 mg/L or more, 13 stayed at or above 5 across the whole three-year range; the other 21 reached it only on a high sample and otherwise ran lower.

Most recent reading Dec 2025; the typical system was last tested around Dec 2024. 1,388 systems sampled their own water; 121 systems carry a supplier’s result.

The named systems

Every reading here belongs to a utility with a name

Highest recent readings
SystemMost recent resultBandBased onPeople served
Lake Panasoffkee Water Assn 2Wps10.20 mg/LMar 2025a high point — runs lowerAbove the federal limit16 samples4,642
Wellington Wtp10.00 mg/LApr 2024Above the federal limit2 samples56,475
Henry George Mobile Home Park9.90 mg/LNov 2024Health-study range6 samples40
Orangewood Water System8.60 mg/LOct 2024a high point — runs lowerHealth-study range16 samples6,464
Jackson Correctional Institution8.50 mg/LDec 2025Health-study range22 samples1,307
The Oasis At Grandfield8.40 mg/LNov 2024a high point — runs lowerHealth-study range5 samples48
Westwood S/D8.40 mg/LJul 2024a high point — runs lowerHealth-study range4 samples344
Dalia Mhp7.70 mg/LDec 2024Health-study range3 samples75
Largest systems
SystemMost recent resultBandBased onPeople served
Mdwasa - Main System0.67 mg/LJul 2024Natural background6 samples2,377,460
Jea Major Grid0.02 mg/LJun 2025Natural background60 samples826,664
City Of Tampa Water Department0.30 mg/LMay 2024Natural background*1 sample733,886
Palm Beach County Water Utilities0.05 mg/LJun 2024Natural background4 samples619,435
Orlando Utilities Commission0.22 mg/LFeb 2025Natural background13 samples536,466

Each result shows its date and what it rests on, so a lone sample is never taken for a settled measurement. A single high sample is not a complete account of what a household drinks.

Where higher nitrate concentrates

Higher results gather in the springs region

Human impact is clear on drinking water served in 15 of Florida’s 67 counties. Each is shaded by how many of its systems reported 3.00 mg/L as N or above. Shading counts systems, not severity — a county with many small utilities can outrank one holding a single larger system that reads higher. The table beside the map splits the two bands so that difference stays visible.

FL counties shaded by number of community water systems reporting nitrate at or above 3.00 mg/L as NCounties are shaded by how many community water systems reported nitrate at or above 3.00 mg/L as N in the three years from August 9, 2023 to August 9, 2026. The same counts appear in the table below this map.Pasco County — 11 systems at 3.00–4.99 mg/L as N; 3 systems at 5.00 mg/L as N or aboveSumter County — 0 systems at 3.00–4.99 mg/L as N; 1 system at 5.00 mg/L as N or abovePalm Beach County — 0 systems at 3.00–4.99 mg/L as N; 1 system at 5.00 mg/L as N or aboveLake County — 5 systems at 3.00–4.99 mg/L as N; 4 systems at 5.00 mg/L as N or aboveLevy County — 1 system at 3.00–4.99 mg/L as N; 0 systems at 5.00 mg/L as N or aboveColumbia County — 1 system at 3.00–4.99 mg/L as N; 0 systems at 5.00 mg/L as N or aboveSanta Rosa County — 2 systems at 3.00–4.99 mg/L as N; 0 systems at 5.00 mg/L as N or aboveSeminole County — 0 systems at 3.00–4.99 mg/L as N; 1 system at 5.00 mg/L as N or aboveGilchrist County — 1 system at 3.00–4.99 mg/L as N; 0 systems at 5.00 mg/L as N or aboveJackson County — 1 system at 3.00–4.99 mg/L as N; 2 systems at 5.00 mg/L as N or aboveEscambia County — 2 systems at 3.00–4.99 mg/L as N; 0 systems at 5.00 mg/L as N or aboveMiami-Dade County — 2 systems at 3.00–4.99 mg/L as N; 1 system at 5.00 mg/L as N or abovePolk County — 6 systems at 3.00–4.99 mg/L as N; 5 systems at 5.00 mg/L as N or aboveMarion County — 14 systems at 3.00–4.99 mg/L as N; 4 systems at 5.00 mg/L as N or aboveHillsborough County — 11 systems at 3.00–4.99 mg/L as N; 12 systems at 5.00 mg/L as N or above
none1–23–56–1112–2526+Number of drinking water systems reporting ≥3.00 mg/L NO₃–N per county as of August 9, 2026

Hillsborough leads this layer with 12 reporting systems, followed by Polk, Lake, Marion. Higher results gather in the springs region.

Counties with the most systems at or above 3 mg/L as N
County3–4.99≥5Total ≥3
Hillsborough111223
Marion14418
Pasco11314
Polk6511
Lake549

Counts use each system's most recent reported result in the current three-year window. A system appears in only one of the two bands.

Find a specific Florida system

What the statewide pattern says

A karst aquifer with the surface wide open

Florida's higher nitrate is a karst story: across the north half of the peninsula the Floridan aquifer is unconfined, and decades of fertilizer nitrogen applied to pastures, citrus and lawns now discharge in its springs.

The Floridan is one of the world's most productive aquifers, and across the north half of the Florida peninsula it is unconfined — rain and everything dissolved in it can reach the aquifer through sinkholes and sandy soils in days to years. Natural background nitrate in Florida springs runs below about 0.01 mg/L, so almost any measurable nitrate in spring water is anthropogenic (Southwest Florida Water Management District).

The source reading in the springs is fertilizer-first. USGS work in the Silver Springs basin found median nitrate of about 1.15 mg/L in urban-area wells and about 1.7 mg/L in agricultural-area wells, with isotope signatures pointing to inorganic fertilizer mixed with septic and wastewater sources (Phelps, 2004). The state’s springs monitoring network reads the same mix: inorganic fertilizer applied to pastures, lawns and citrus — much of it applied decades ago — with on-site wastewater as the secondary source (Florida DEP, 2010).

The map on this page follows that footprint: Hillsborough, Marion, Pasco, Polk and Lake counties sit inside the Southwest Florida Water Management District’s springs country, where the aquifer is shallow and the time lag from surface to spring is short enough that land use shows up directly in groundwater.

The supported source reading is fertilizer nitrogen, with on-site wastewater secondary, on an unconfined karst aquifer — not a certified source at any individual system. That is the same land-use-plus-fast-pathway combination the national vulnerability work ties to high nitrate (Nolan and Hitt, 2006).

The general science — how nitrate moves, why some ground is vulnerable, and why the legacy lingers — is laid out with its sources on Where nitrate comes from.

Questions this page answers

What the Florida pattern does—and does not—say

Where does nitrate concentrate in Florida community water systems?

Hillsborough leads this layer with 12 reporting systems, followed by Polk, Lake, Marion. Higher results gather in the springs region.

Why do Florida's springs matter to well owners?

Springs are the Floridan aquifer's discharge points, so their nitrate is a direct sample of what the aquifer carries. Background is below about 0.01 mg/L; the elevated nitrate now measured in many springs is fertilizer nitrogen applied on the surface decades ago, which is the same water nearby private wells draw.

Is septic or fertilizer the bigger Florida source?

Studies point to inorganic fertilizer first — pastures, citrus and lawns — with septic and wastewater a real but secondary contributor. USGS isotope work at Silver Springs found the fertilizer signal dominant; the state's springs network reads the same mix. No reading certifies the source at an individual system.

Does a high public-system result mean a nearby private well is high?

No. It is a local sentinel, not a well-specific result. It shows that nitrogen and a transport pathway have reached groundwater in the area; a certified-lab test is still the only way to know a specific private well.

Sources and provenance

What this page rests on

  1. NitrateSmart inventory: 1,509 Florida community water systems with a current nitrate result in the three years from August 9, 2023 to August 9, 2026. Figures count people served by reporting systems, not measured tap exposure.
  2. Nolan BT, Hitt KJ (2006). Vulnerability of Shallow Groundwater and Drinking-Water Wells to Nitrate in the United States. Environmental Science & Technology 40(24):7834–7840.
  3. Dubrovsky NM, and others (2010). Nutrients in the Nation's Streams and Groundwater, 1992–2004. USGS Circular 1350.
  4. Southwest Florida Water Management District. Hydrology and Water Quality of Select Springs — natural background nitrate in Florida springs below about 0.01 mg/L; springs nitrate derived primarily from inorganic fertilizer.
  5. Phelps GG (2004). Chemistry of Ground Water in the Silver Springs Basin, Florida, with an Emphasis on Nitrate. USGS Scientific Investigations Report 2004-5144 — urban wells median 1.15 mg/L, agricultural wells 1.7 mg/L; isotopes point to inorganic fertilizer mixed with septic and wastewater.
  6. Florida Department of Environmental Protection (2010). Florida Springs Initiative Monitoring Network Report — statewide springs nitrate monitoring and recognized nitrogen sources.