Florida’s Advanced Wastewater Treatment Mandate: What AWT Requirements Near Impaired Waters and Springs Add to a Project’s Treatment Design

Near impaired waters and springs, Florida advanced wastewater treatment turns a secondary plant into a nutrient removal plant. Total nitrogen drops to 3 mg/L, phosphorus to 1 mg/L and suspended solids to 5 mg/L, with high-level disinfection on top. It already covers Tampa Bay, Biscayne Bay and the Indian River Lagoon, and nutrient-impaired waters join by 2033. Settle it before you lock the site plan.

What does advanced wastewater treatment mean in Florida?

Reclaimed water at or below 5 mg/L CBOD5, 5 mg/L suspended solids, 3 mg/L total nitrogen and 1 mg/L total phosphorus on a permitted annual average, plus high-level disinfection.

Those numbers come from section 403.086(4), Florida Statutes. FDEP can relax phosphorus where it is not a limiting nutrient. The secondary baseline in Rule 62-600.420, F.A.C. is 20 mg/L CBOD5 and suspended solids as annual averages for surface water and reuse, with no nutrient number at all.

Rule 62-600.740, F.A.C. checks AWT plants at 1.25 times the design value as a monthly average, 1.5 times weekly and 2 times in any single sample. For nitrogen, that is 3.75, 4.5 and 6 mg/L. One bad week can be a violation.

Which Florida waters require advanced wastewater treatment?

Listed bays and their tributaries now, the Indian River Lagoon since July 1, 2025, and by January 1, 2033, waters not attaining nutrient standards or covered by a nutrient basin management action plan (BMAP) or reasonable assurance plan.

Section 403.086(1)(c) names Tampa Bay, Sarasota Bay, Biscayne Bay and nine other bays and sounds, plus the waters tributary to them. A water found impaired for nutrients, or placed under a nutrient BMAP, after July 1, 2023 gets 10 years from that finding or plan. Section 403.086(1)(a) also lets FDEP order AWT wherever it deems it necessary.

FDEP's impaired waters assessment lists include the Verified List and a Waters Not Attaining Standards map. Under section 403.067(7)(a)9., F.S., where wastewater plants or septic systems contribute at least 20 percent of the nutrient load, the BMAP includes a local domestic wastewater treatment plan, and private facilities must supply their data.

For utilities and municipalities with a plant on one of these waters, 2033 is a capital planning deadline, not a permit footnote.

What do springs add to a wastewater project?

Inside a BMAP for an Outstanding Florida Spring, a new disposal facility of 100,000 gallons per day or more, rapid infiltration basins included, must meet 3 mg/L total nitrogen or stricter.

Section 373.811, F.S. sets that cap. Section 373.802, F.S. defines Outstanding Florida Springs as the historic first magnitude springs plus six named springs, Wekiwa and Rock Springs among them. FDEP's springs restoration page says 24 are listed as impaired, covered by 13 restoration plans adopted in June 2018.

Septic is limited too. Section 373.811 bars new septic systems in those BMAP areas where sewer is available, and on lots of 1 acre or less without sewer allows only systems that remove at least 65 percent of nitrogen. On a subdivision, that pushes the plan toward central sewer or a package plant. The target is tight: Rule 62-302.531, F.A.C. sets 0.35 mg/L nitrate-nitrite, as an annual geometric mean, for spring vents.

Does reuse or land application avoid AWT?

Not reliably. In springs basins and some nutrient BMAPs, Florida applies nutrient limits to land disposal and irrigation reuse too.

• By July 1, 2034, section 403.086(1)(c)3. requires plants supplying irrigation reuse inside a nutrient BMAP to meet the AWT nitrogen and phosphorus limits, where the plan finds that reuse is contributing to the impairment. A finding after July 1, 2024 gets 10 years instead.
• Rule 62-600.430, F.A.C. requires extra treatment when needed to meet groundwater standards.

Reuse still shapes the design. For public access reuse, Rule 62-610.464, F.A.C. requires system storage of at least three days of average flow for capacity without a permitted alternative, or a limited wet weather discharge permit. Off-spec water needs one day of reject storage unless another permitted system can take it. Section 403.086(8) caps a backup discharge at 30 percent of permitted reuse capacity per year.

How does AWT change process selection and footprint?

Plan on biological nitrogen and phosphorus removal, chemical feed, effluent filtration, high-level disinfection and often a supplemental carbon feed.

To reach limits like 3 mg/L total nitrogen, EPA's Nutrient Control Design Manual says plants typically combine biological nutrient removal, chemical addition and effluent filtration. A 4-stage Bardenpho process adds a second anoxic zone and a reaeration zone, so it takes more footprint than the Modified Ludzack-Ettinger process, and it typically needs an external carbon source such as methanol unless that second anoxic zone is very large. At 3 mg/L or less, the manual notes, dissolved organic nitrogen that resists biology, typically 0.5 to 1.5 mg/L, can limit removal. That eats a big share of your margin.

High-level disinfection under Rule 62-600.440, F.A.C. means 75 percent of fecal coliform results below detection over 30 days, no sample above 25 per 100 mL, and no more than 5.0 mg/L suspended solids before the disinfectant. UV designs must evaluate short power interruptions and the possible need for an uninterruptible power supply.

Our post on choosing a package plant or a custom-designed plant covers whether a factory-built unit fits.

What does AWT add to operations and reliability?

More operator hours, more sampling and less room for a bad week.

Rule 62-699.310, F.A.C. puts any plant with a nitrogen or phosphorus limit in Category I. A 0.2 mgd extended aeration plant with no nutrient limit needs a Class C operator half an hour a day, five days a week, plus a weekend visit. With a nitrogen limit, that plant needs six hours a day, five days a week, plus a visit on each weekend day.

The permit sets sampling, and Rule 62-600.650, F.A.C. lets FDEP raise the minimums for the level of treatment. Public access reuse needs Class I reliability under Rule 62-610.462, F.A.C. unless a permitted alternate system can take off-spec water. Section 403.086(2) also requires a power outage contingency plan for the collection system and pump stations.

Is your Florida project ready for an AWT decision?

Six yeses mean you are ready to size the plant. Any no is the next thing to settle.

1. Do you know which waterbody or disposal site receives the effluent?
2. Have you checked that water against the Verified List, the Waters Not Attaining Standards map and any adopted BMAP, springs included?
3. Have you confirmed whether the design flow is 100,000 gallons per day or more?
4. If you plan irrigation reuse, have you checked whether the BMAP finds reclaimed water contributing to the impairment?
5. Is the process designed to hold the monthly and weekly compliance values, not just the annual average?
6. Have you planned operator hours, sampling, wet weather storage and reject storage?

Answer these in a site feasibility study, before the land plan fixes the plant pad and the disposal area. Then ask your engineer: if our receiving water gets listed after we permit, what is our upgrade path?

A note on limits: this is general education from Florida statutes, FDEP rules and EPA guidance as of October 2026. BMAPs, impaired waters lists and deadlines change, your permit governs, and no article can predict an FDEP review outcome or schedule.

Frequently asked questions

Does every Florida wastewater plant need AWT?

No. Secondary treatment is the baseline. AWT applies to the named bays, the Indian River Lagoon, nutrient-impaired and BMAP waters by 2033 (or 10 years after a later listing), and wherever FDEP orders it. Springs BMAPs add a 3 mg/L nitrogen cap on large new disposal facilities.

Does Florida's AWT law apply to septic systems?

No. Section 403.086(3) says it does not regulate septic tanks. Springs BMAPs differ, because section 373.811 limits new septic systems there.

I'm a developer planning a 300-home subdivision in North Central Florida near a first magnitude spring, and no utility can serve us yet. What nitrogen limit should our plant design for?

First confirm whether the site is inside that spring's BMAP. If it is and the plant is 100,000 gpd or more, design for 3 mg/L total nitrogen as an annual average, or stricter if the spring's total maximum daily load needs it. Otherwise the permit sets the limit, so ask the FDEP district office before you size the plant.

I run a small Florida utility whose plant discharges to a creek FDEP just found impaired for nutrients. How long do we have to reach AWT, and does switching to reuse buy us time?

For a finding made after July 1, 2023, section 403.086(1)(c)2. allows 10 years. Reuse cuts the discharge, but if a later nutrient BMAP finds irrigation reuse feeds the impairment, the reuse plant gets 10 years from that finding to meet AWT nutrient limits. Confirm which date applies to your permit.

Related resources

• FDEP Permitting for Wastewater Systems in Florida: A Practical Guide for Developers
• Florida Numeric Nutrient Criteria: How the State’s Nutrient Limits Reshape Treatment Plant Sizing Versus Texas or Colorado
• Water Reuse in Florida: How the State’s Progressive Rules Are Shaping Infrastructure Design
• How to Navigate FDEP’s OSTDS Upgrade Program: A Guide for Florida Property Owners and Developers

Siting a Florida plant near a spring or an impaired water?

We confirm the receiving water and the AWT trigger first, then size the treatment, storage and operations around the limits that will actually apply.

Modern Engineering Solutions is licensed in Florida. Talk to us about your project, or call (214) 833-6748.