Understanding Beach Water Quality Advisories in Florida

When you see a water quality advisory at a Florida beach, it means bacteria levels have exceeded safe swimming thresholds. Here's everything you need to know about what those numbers mean and how to stay safe.

What Gets Tested?

The Florida Department of Health (DOH) Healthy Beaches Program monitors saltwater beaches for enterococcus bacteria. Enterococcus is an indicator organism — its presence suggests fecal contamination from human or animal sources, which could mean other harmful pathogens are present too.

Enterococcus is used (rather than testing for every possible pathogen) because it's reliable, fast to measure, and correlates well with the risk of gastrointestinal illness from swimming in contaminated water.

The Three Levels

Florida uses the U.S. EPA's Beach Action Value (BAV) as the threshold for health advisories. On Safe to Swim Florida, we break results into three clear categories:

What Is CFU/100mL?

CFU stands for Colony-Forming Units. The measurement "CFU/100mL" tells you how many bacteria colonies were found in a 100-milliliter sample of water. A reading of 12 CFU/100mL means 12 bacteria colonies were found — well within safe limits. A reading of 150 CFU/100mL means significantly more bacteria, well above the advisory threshold.

How Often Are Beaches Tested?

The DOH Healthy Beaches Program samples monitored beaches at least twice per month (bi-weekly). Some high-traffic beaches may be tested weekly. Key things to know:

• Results typically take 24–48 hours to process after sample collection.
• Testing does not happen during weekends or holidays.
• Storms or other events may delay scheduled testing.
• Conditions can change between test dates — a "Good" result from last week doesn't guarantee today's conditions.

What Happens When an Advisory Is Issued?

When enterococcus levels exceed 70.5 CFU/100mL, the county health department:

1. Issues a health advisory for the affected beach.
2. Posts advisory signs at the beach (in most counties).
3. Conducts follow-up testing — usually within a few days.
4. Lifts the advisory once bacteria levels return to safe levels (below the threshold on follow-up testing).

Health Risks of Swimming in Contaminated Water

Swimming in water with elevated bacteria levels can cause:

• Gastrointestinal illness — Nausea, vomiting, diarrhea, stomach cramps
• Skin infections — Rashes, irritation, especially through open wounds or cuts
• Eye and ear infections — Redness, irritation, swimmer's ear
• Respiratory issues — From inhaling water spray or mist

Symptoms typically appear within 24–48 hours of exposure. Children, elderly individuals, and people with weakened immune systems are at higher risk and may experience more severe symptoms.

What About Red Tide?

Red tide (caused by the algae Karenia brevis) is a separate issue from bacteria testing. Red tide produces toxins that can irritate skin and respiratory systems, and can kill fish in large numbers. The Florida Fish and Wildlife Conservation Commission (FWC) monitors red tide separately.

Check our Red Tide Tracker for current conditions.

How to Use Safe to Swim Florida

1. Search for your beach or browse by county.
2. Check the status badge — Green (Good), Yellow (Moderate), or Red (Poor/Advisory).
3. Look at the historical risk rating — a beach with a low percentage of poor results is generally more reliable.
4. Check the test date — if the last test was more than a week ago, conditions may have changed.
5. Read the swimming after rain guide if there's been recent rainfall.