Test private well water at least once a year for total coliform bacteria and nitrate, the two indicators the CDC highlights for private wells, plus pH and total dissolved solids per EPA guidance. In Florida, add an immediate test after flooding, well repairs, or any change in taste, color or smell.
How often should you test well water?
The baseline answer from federal guidance is simple: once a year, every year. The CDC recommends testing private wells annually for total coliform bacteria and nitrate, and the EPA's private well guidance adds pH and total dissolved solids to that yearly check. These four parameters act as an early-warning system: coliform reveals whether surface contamination can reach your water, nitrate flags septic or fertilizer influence, and pH and dissolved solids show whether the chemistry of the well is drifting.
Why yearly and not once per well? Because groundwater is not static. Rainfall, drought, pumping, nearby construction and aging well components all change what arrives at your tap. This matters even more in Florida, where the karst limestone that holds our groundwater is porous and full of channels, so water, and anything dissolved in it, moves between the surface and the aquifer faster than in many other states. A well that tested clean in 2024 says little about the same well after two hurricane seasons.
What should you test for every year?
The annual test is intentionally short and affordable. It covers the indicators most likely to change, and most likely to matter for health:
| Parameter | What it tells you | Recommended by |
|---|---|---|
| Total coliform bacteria | Whether surface contamination has a pathway into the well | CDC, EPA, Florida DOH |
| Nitrate | Septic, fertilizer or animal waste influence; risk for infants | CDC, EPA |
| pH | Corrosivity toward pipes and fixtures | EPA |
| Total dissolved solids | Overall mineral load and changes in the aquifer | EPA |
If the coliform result comes back positive, that opens its own decision tree, confirmation, well inspection and disinfection, which we cover step by step in what a positive coliform test means. Nitrate deserves special respect in homes with infants: the EPA's limit for public systems is 10 mg/L of nitrate-nitrogen, set to protect babies from methemoglobinemia, and private well owners are wise to use the same number as their personal ceiling.
What should you test every few years?
Beyond the annual basics, university extension programs such as UF/IFAS recommend running a broader panel periodically, commonly every three years or so, and whenever you are diagnosing a treatment problem. This panel looks at the slower-moving chemistry of your water:
- Iron and manganese, the metals behind orange and brown staining (covered in our guide to iron stains from well water).
- Hardness, which determines scale buildup and softener sizing, a near-universal issue over Florida's limestone aquifers.
- Sulfate and hydrogen sulfide, the rotten egg family.
- Lead and copper, which usually enter from household plumbing when water is corrosive, rather than from the aquifer itself.
- Arsenic and other metals, worth a baseline at least once for any well, and again if land use nearby changes.
Think of it as two layers: the annual test guards against contamination events, and the periodic panel keeps your treatment design matched to the water. The full picture of what lives in Florida groundwater, and how each problem is treated, is in our complete Florida well water guide.
When should you test immediately?
Some events override the calendar. The CDC and EPA both publish trigger lists for out-of-schedule testing, and Florida's climate makes several of them routine here:
- Flooding reached the wellhead. The Florida Department of Health treats a flooded well as contaminated until it is disinfected and a bacterial test comes back clean. After hurricanes, county health departments often announce free or low-cost well testing.
- The water changed. New taste, odor, color or cloudiness is a test trigger, not just an annoyance.
- Work was done on the well. Pump replacement, casing repair, or opening the well cap for any reason can introduce bacteria.
- A baby or pregnancy in the home. Test for nitrate before an infant drinks the water or formula made with it.
- Unexplained stomach illness in the household, especially if guests get sick on your water while residents seem fine.
- Septic problems or land use changes nearby, a failing drain field, new agriculture, or construction around your lot.
Where do you get well water tested in Florida?
Florida gives well owners more infrastructure than most states. The Florida Department of Health runs a well surveillance program that samples private wells in areas of known contamination, and county health departments sell sample kits and run bacteriological and nitrate analyses through certified labs. For broader panels, any laboratory certified by the state can analyze your sample; the DOH maintains guidance on choosing one through its Healthy Drinking Water Program.
The practical workflow most Florida well families settle into looks like this: a certified lab test for the health indicators on the annual schedule, plus an on-site working test whenever treatment is being designed or checked, hardness, iron, pH and chlorine measured at the tap, where the answers are immediate. Prevent Water provides that on-site screening free at your home, and our well water treatment page shows what we do with the results. For the bigger question behind all this testing, read whether Florida well water is safe to drink without treatment.
Frequently asked questions about well water testing
Is one water test enough if my well has always been fine?
No. Groundwater quality changes with rainfall, drought, nearby construction, septic performance and the age of your well. A clean result is a snapshot, not a guarantee, which is exactly why the CDC and EPA recommend repeating the basic bacteria and nitrate test every year even when previous results were good.
How much does a well water test cost in Florida?
County health department labs in Florida typically charge a modest fee per sample for bacteriological and nitrate analysis, and certified private labs offer broader panels at higher prices depending on how many contaminants you include. Prevent Water also runs a free on-site screening of hardness, chlorine and other indicators at your home as a starting point.
Do new wells in Florida need to be tested?
Yes. New private wells in Florida are tested for bacteria as part of the permitting and construction process, but that initial clearance only reflects day one. After you move in, the well enters the same annual testing routine as any other private well, because conditions around it keep changing.
Should I test my well after every hurricane?
Test after any event where floodwater reached or covered the wellhead, or where the well lost power and pressure for an extended period. The Florida Department of Health advises assuming a flooded well is contaminated until it has been disinfected and a bacteriological test comes back clean.
What is the difference between a lab test and an in-home water test?
A certified lab test quantifies health-related contaminants like coliform bacteria, E. coli and nitrate, and is the right tool for safety decisions. An in-home test measures working parameters like hardness, iron, pH and chlorine on the spot, which is what you need to design treatment for staining, odor and scale. The two are complementary, not interchangeable.
Sources
- Centers for Disease Control and Prevention. Private Wells: testing recommendations (annual total coliform and nitrate). cdc.gov
- U.S. Environmental Protection Agency. Private Drinking Water Wells, testing guidance and the 10 mg/L nitrate standard. epa.gov
- Florida Department of Health. Private Well Testing and the Healthy Drinking Water Program. floridahealth.gov
- University of Florida IFAS Extension. EDIS publications on private well testing and domestic water quality. edis.ifas.ufl.edu
- U.S. Geological Survey. Domestic (private) supply wells and groundwater quality. usgs.gov