Florida's ENR septic requirements decide what kind of septic system you can install, and what you must install when an old one fails. ENR stands for enhanced nutrient-reducing: a system that removes at least 65% of the nitrogen in household wastewater before it reaches groundwater. A statewide law has required these systems on small lots in protected springs and water-quality areas since 2023. In Marion County, the 2025 Silver Springs and Rainbow Springs plan goes further: it reaches every lot size for new systems and adds a repair trigger for existing ones. This guide sets out the rules, the dates, the approved system types and the current rebate picture, with links to DEP's own table and map.
This is general information, not legal advice. Rules, tables and programs change. Check the current statute, rule or DEP table, or contact the agency named, before you rely on anything here.
The statewide rule: HB 1379 (2023)
House Bill 1379 (chapter 2023-169, Laws of Florida) took effect July 1, 2023. It added this language to s. 403.067(7)(a)10, Florida Statutes: “On lots of 1 acre or less within a basin management action plan… where a publicly owned or investor-owned sewerage system is not available, the installation of enhanced nutrient-reducing onsite sewage treatment and disposal systems or other wastewater treatment systems that achieve at least 65 percent nitrogen reduction is required.” The same section prohibits new septic systems inside a BMAP where sewer is available. Section 373.811(2) carries parallel text for the plans that protect Outstanding Florida Springs.
DEP puts it simply: “starting July 1, 2023, permit applicants for new septic systems serving lots of one acre or less within impacted areas must install a nitrogen-reducing system.” Applications that were complete before that date were exempt. A “new” system is one installed where no system has been before, plus other cases DEP lists, such as a system that replaces an illegal one or is added next to an existing one.
BMAPs that matter in central Florida
A BMAP (basin management action plan) is DEP's cleanup plan for a polluted water body. The ENR rules apply only inside BMAP boundaries, so the first question is always which plan, if any, covers your lot. The plans this research found for central Florida are:
- Silver Springs & Upper Silver River and Rainbow Spring Group & Rainbow River BMAP. It covers parts of Marion, Alachua, Putnam, Lake, Sumter and Levy counties. Research found most of Marion County inside it.
- Orange Creek BMAP. DEP's map also places the Citra and Reddick test points in this plan, in addition to Silver/Rainbow.
- Wekiwa Priority Focus Area (Orange County). This is where Orange County's own upgrade incentive applies.
- Santa Fe River and Silver Springs basins in Alachua County. These are the areas Alachua County's rebate covers.
Inside the Silver/Rainbow BMAP, DEP also draws smaller Priority Focus Areas (PFAs), where the aquifer is most vulnerable. Downtown and northeast Ocala, Silver Springs, Silver Springs Shores and Anthony fell inside the Silver PFA at the points checked. Spot checks are not a parcel answer. Use DEP's own address lookup at floridadep.gov/BMAPs-ARP-OSTDS, and read DEP's August 2026 ENR requirements table for the rule that applies in each plan.
Marion County's stricter rule: the Silver Springs & Rainbow Springs BMAP
DEP signed the current Silver/Rainbow BMAP on June 27, 2025 (final order OGC 25-1040). A challenge was dismissed in April 2026, and DEP's amended order closing the file on April 27, 2026 states: “The BMAP is final and effective as of the date of this order.” The 2025 plan replaces the 2018 plan in its entirety.
New systems, any lot size. The plan was “updated in this BMAP iteration to prohibit the installation of new OSTDS on any lot size within the BMAP boundary unless the systems are enhanced nutrient-reducing OSTDS systems or other wastewater treatment systems that achieve at least 65% nitrogen reduction.” DEP's August 2026 table marks the Silver/Rainbow BMAP as requiring ENR for a new system on any size lot as of July 27, 2026, and on lots of one acre or less since July 1, 2023. So in most of Marion County, the one-acre limit in the state law no longer helps a new build or a lot where no system existed. A conventional system is no longer an option for new systems in the BMAP; see our septic system installation page for how quotes work.
The repair trigger for existing systems
The part of the plan that reaches the most Marion homeowners is in Appendix E.1.2: “Upon the need for any construction permit under chapter 62-6, F.A.C. to repair, modify, or replace an existing OSTDS affected by the remediation policy, a DEP-approved enhanced nutrient reducing system meeting at least 65% nitrogen reduction must be installed unless the OSTDS permit applicant provides documentation that sewer connection to the property is planned and funded, and structures on the lot will be connected.” The plan says this policy “applies to all existing OSTDS within the BMAP and is effective upon BMAP adoption,” and DEP's table lists repair and modification permits in Silver/Rainbow as “any size lot in the BMAP requires ENR.”
What this means in practice:
- A fully working system with no permit need does not have to change anything now.
- When a drain field, tank or other part fails and the fix needs a DEP repair, modification or replacement permit, the permit will call for an ENR system, not a like-for-like repair.
- Storm damage counts. A repair permit after a hurricane triggers the same rule.
- Home sales: no government may require a septic inspection at the point of sale in Florida (s. 381.0065(4)(x)), but if a buyer's inspection finds a failure that leads to a repair permit, the ENR rule applies.
Since July 1, 2025, Florida DEP's Onsite Sewage Program, not the county health department, issues septic permits in Marion County. Apply online at osp.floridadep.gov, or email Marion County program staff at [email protected] or call 850-245-8362. Our Florida septic permits guide covers the process.
The 20-year deadline
The plan also sets a long-term requirement for every conventional system in the remediation area, failing or not. Appendix E.1.3: “All conventional OSTDS in areas subject to the remediation policy for existing systems are required to meet enhanced nutrient reducing OSTDS requirements… or connect to central sewer no later than 20 years after BMAP adoption.”
The safe way to state it is: within 20 years of the plan's adoption. DEP's documents and county guidance give different years for this deadline, so do not plan around a single date until DEP confirms one. If sewer is planned for your street, connecting is the other way to meet it; see our septic-to-sewer guide.
Approved ENR septic system types
DEP's ENR fact sheet (version 1.2, August 2025) lists three approved kinds of system:
- In-ground nitrogen-reducing biofilters (INRBs): in-ground systems that use treatment media to remove nitrogen.
- Nitrogen-reducing aerobic treatment units (ATUs): Florida-approved units certified to NSF 245.
- Nitrogen-reducing performance-based treatment systems (PBTS): engineered systems approved by Florida.
Florida Realtors (September 29, 2026) puts the cost of an ENR system at “approximately $15,000 to $35,000 or more.” That is an estimate, not a quote; the ENR septic system cost guide breaks it down. Note that the 2025 fact sheet still describes the one-acre limit, so read it together with the August 2026 table.
Owning an aerobic treatment unit: the ongoing obligations
An ATU has moving parts and a permit that never really ends. Under s. 381.0065(4)(v), the owner “shall maintain a current maintenance service agreement with an aerobic treatment unit maintenance entity permitted by the department. The maintenance entity shall inspect each aerobic treatment unit system at least twice each year.” The owner also needs a DEP operating permit; DEP's fee under Rule 62-6.030 is $100 every two years. Budget for the maintenance contract as well as the install, and ask any company you talk to for its DEP maintenance-entity permit.
Rebates and incentives: what exists in 2026
Marion County: no open ENR rebate in Marion County could be verified (checked October 2026). DEP's Septic Upgrade Incentive Program, which paid up to $10,000 per system to installers in springs Priority Focus Areas, is no longer accepting new applications. DEP says it is working with Marion and other counties to set up county-specific programs. Marion's “Run for the Springs” grant (up to $200 toward a pump-out and inspection, or $250 toward a repair permit) has an unknown current status; ask the county before counting on it. Marion's septic-to-sewer grant covers designated Program Areas only.
Other counties: Orange County's program offers up to $10,000, but only in the Wekiwa Priority Focus Area within the Orange County Utilities service area. Alachua County offers up to $10,000 for an INRB and up to $16,000 for an ATU, but only in the Santa Fe River and Silver Springs basin parts of Alachua County. Neither is open to Marion properties.
Why septic matters for Silver and Rainbow Springs
Silver Springs and Rainbow Springs are both Outstanding Florida Springs, and both are impaired by nitrate. Their target is a long-term monthly average of 0.35 mg/L; the 2025 BMAP reports recent median nitrate in springshed wells of 0.76 mg/L for Silver (2021–2024) and 1.44 mg/L for Rainbow. The plan's estimate of where the nitrogen comes from has changed over the years:
| Document | Area | Septic share of nitrogen |
|---|---|---|
| Rainbow Springs BMAP, Dec 2015 | Rainbow | 19% of nitrogen to the Upper Floridan aquifer |
| Silver & Rainbow BMAP, June 2018 | Silver | 29% of nitrogen loading to groundwater |
| Silver & Rainbow BMAP, June 2018 | Rainbow | 20% |
| Silver & Rainbow BMAP, June 27, 2025 (current) | Combined | 32% (1,265,209 lb of nitrogen a year), tied with agriculture and ahead of urban turf fertilizer (20%) |
The 2025 plan counts about 103,960 septic systems inside the BMAP (2023 inventory data), including about 28,188 in the Silver PFA and 3,724 in the Rainbow PFA. On Marion's sandy ridges, effluent moves quickly through the soil to the aquifer, which is why DEP treats these areas as the most vulnerable.
ENR septic requirements by county
This table covers only the counties the research checked. It is a summary; DEP's table and your county permit office have the final word.
| County | Who issues septic permits | ENR rule | Upgrade rebate |
|---|---|---|---|
| Marion | Florida DEP (since July 1, 2025) | Most of the county is in the Silver/Rainbow BMAP: ENR for new systems on any lot size (as of July 27, 2026) and for repair or modification permits | None open that could be verified (Oct 2026) |
| Alachua | County health department | Parts lie in the Silver/Rainbow BMAP; the BMAP rules apply inside its boundary | Up to $10,000 (INRB) or $16,000 (ATU) in the Santa Fe and Silver basin parts of the county |
| Lake, Sumter, Levy, Putnam | County health departments | Parts lie in the Silver/Rainbow BMAP; the BMAP rules apply inside its boundary | Not researched |
| Orange | County health department | Check DEP's table for the BMAP covering your lot | Up to $10,000 in the Wekiwa PFA within the Orange County Utilities service area |
Inside Marion, two areas need extra care. Most of Marion Oaks may sit outside the BMAP, and the Fort McCoy town area tested outside it too. Most of Marion County is inside the BMAP; confirm your parcel on DEP's map.
What to do next
Look up your parcel
Use DEP's BMAP map and the August 2026 table linked above to see which plan, if any, applies.
Know your trigger
If your system works, keep it maintained; routine pumping keeps solids out of the drain field. If it needs a repair, expect the permit to call for ENR.
Check every contractor
Ask for the company's DEP septic tank contractor registration number and verify it through DEP's contractor search, linked from floridadep.gov/SepticContractorRegistration. Ask for proof of insurance and a written quote, and for an ATU, the maintenance agreement terms.
Florida Septic Works connects Ocala and Marion County homeowners with independent local septic companies for free, no-obligation quotes. Florida Septic Works is a referral service, not a septic tank contractor; the work is done by independent DEP-registered septic tank contractors, who quote, contract and do the job. Request a free quote to compare ENR options, or start with a septic inspection.
Frequently asked questions
Do I have to replace my working septic system with an ENR system in Marion County?
Not right now. Under the Silver Springs and Rainbow Springs BMAP, an existing system must be upgraded to ENR when it needs a DEP permit to repair, modify or replace it, unless sewer is planned and funded. A fully working system with no permit need does nothing today. The plan also requires conventional systems to be upgraded or connected to sewer within 20 years of its adoption.
Does the one-acre exemption apply in Marion County?
No, not inside the Silver Springs and Rainbow Springs BMAP. The statewide HB 1379 rule covers lots of one acre or less, but DEP's August 2026 table says any size lot in this BMAP requires ENR for a new system as of July 27, 2026. Parts of Marion Oaks and the Fort McCoy area may sit outside the BMAP, so confirm your parcel on DEP's map.
Is there a rebate for an ENR septic upgrade in Marion County?
No open ENR rebate in Marion County could be verified when this page was checked in October 2026. DEP's Septic Upgrade Incentive Program, which paid up to $10,000 to installers, stopped taking new applications, and DEP says it is working with Marion on a county program. Orange and Alachua counties run their own programs, but only for properties in their areas.
This is general information, not legal advice.