If your Merritt Island home is on septic, a 2023 Florida law gives you a deadline. By July 1, 2030, you must connect to central sewer or switch to a nitrogen-reducing septic system. That can sound scary, and it is a real expense. But it is also manageable, especially with the county's grant program. This guide explains the law, the system types, the costs and the steps for a septic upgrade in Merritt Island in plain language.
What is a nitrogen-reducing septic system?
A regular septic system has two main parts: a tank where solids settle, and a drain field where the liquid soaks into the ground. It does a decent job with germs, but it lets most of the nitrogen through. In sandy island soil, that nitrogen moves into the groundwater and then into canals and the lagoon, where it feeds algae.
A nitrogen-reducing system adds a treatment step that changes nitrogen into harmless nitrogen gas before the water leaves your property. The state's official name is an enhanced nutrient-reducing onsite sewage treatment and disposal system, or ENR-OSTDS. Contractors and county staff often just say "ENR septic," "nitrogen-reducing system" or "advanced septic." They all mean the same idea.
Florida's septic law for 2030 (HB 1379), explained
In 2023, the Florida Legislature passed HB 1379. It created the Indian River Lagoon Protection Program, which covers parts of Volusia, Brevard, Indian River and St. Lucie counties, including Merritt Island. Inside that area, the law sets two rules:
- New systems: since January 1, 2024, any new septic system must be a nitrogen-reducing system when central sewer is not available.
- Existing systems: by July 1, 2030, every home or business with an existing septic system must either connect to central sewer or upgrade to an enhanced nutrient-reducing system that removes at least 65% of the nitrogen.
Brevard County was ahead of the state on this. Since 2018, the county has banned new conventional septic tanks on Merritt Island, on the beachside and near the lagoon on the mainland.
A note on dates: the law and the Florida Senate's bill summary say July 1, 2030. You may see other dates in older materials, so plan around July 1, 2030 and confirm with the county for your address.
Do I need to upgrade? A quick checklist
Go down this list. If the first three are true, the 2030 rule almost certainly applies to your property.
- The property is on Merritt Island or elsewhere in the lagoon protection area.
- It uses a septic system, not central sewer.
- The system is a standard tank and drain field, not an approved nitrogen-reducing design.
- There is no sewer line available to connect to, or none is planned in time.
- You would like the county grant, which requires approval before work starts.
Not sure what kind of system you have? Your permit history may be on file with the county health department, or a contractor can check during a septic inspection.
Your three main upgrade options
The state approves several kinds of enhanced nutrient-reducing systems. On Merritt Island, most upgrades use one of these.
Aerobic treatment unit (ATU)
An ATU is a tank with a small air pump, or blower, that feeds oxygen to bacteria. The bacteria break down waste much more completely than in a regular tank. To count for the 2030 rule, the unit must be certified for nitrogen reduction. ATUs are compact, which helps on small island lots, but they use electricity, have moving parts and need a maintenance contract and an operating permit.
In-ground nitrogen-reducing biofilter (INRB)
An INRB is a specially built drain field. Under the usual layer of sand, it adds a layer of material that helps natural bacteria strip out nitrogen. It is passive, so there is no blower and no electric bill. It usually needs more room and more careful design, which can be harder with a high water table.
Other approved nitrogen-reducing systems
The state also allows certain performance-based treatment systems that have been tested for nitrogen reduction. These are less common for single-family homes, but a contractor may suggest one for a tricky lot.
Conventional vs. ATU vs. in-ground biofilter
| Feature | Conventional septic | Aerobic treatment unit (ATU) | In-ground nitrogen-reducing biofilter |
|---|---|---|---|
| Meets the 2030 nitrogen rule | No | Yes, if certified for nitrogen reduction | Yes, when built to state design |
| Allowed for new installs on Merritt Island | No | Yes | Yes |
| How it treats nitrogen | Very little treatment | Air and bacteria inside the unit | Special media layers under the drain field |
| Electricity | Usually none | Yes, runs a blower | Usually none |
| Space needed | Moderate | Smaller footprint | Larger footprint |
| Upkeep | Pumping every few years | Service contract, operating permit, regular checks | Pumping and periodic checks |
| Best fit | Not an option here | Small lots, tight spaces, high water table | Larger lots with room to build up |
The right choice depends on your soil, water table, lot size and budget. Your contractor will recommend a system after the site evaluation.
How a septic upgrade in Merritt Island works
- Check sewer first. If central sewer is available or coming soon, connecting may be required or cheaper. See septic to sewer.
- Check your grant amount. Use the county's Septic Mapper to see what your parcel may get, then apply. You must be approved before work starts.
- Site evaluation. The contractor measures soil, groundwater and space and checks your current system.
- Design and permit. The contractor designs the system and applies for the permit with the Florida Department of Health in Brevard County, or the Florida DEP once septic permitting for Brevard moves there.
- Installation. The old tank is pumped and removed or abandoned, and the new system goes in.
- Inspection and approval. The work is inspected before it is covered, then approved.
- Grant paperwork. Final documents are filed so the county can pay the grant, sometimes directly to the contractor.
What does a nitrogen-reducing septic system cost?
Brevard County staff have said the average septic upgrade in the county now costs more than $22,000, up from about $18,000 in 2020. Your price could be higher or lower. It depends on the system type, how high the water table is, how much fill is needed, access to the yard and permit costs.
The county's Save Our Indian River Lagoon grant can pay up to $20,000 for an eligible parcel. In December 2025, commissioners approved a guaranteed $6,000 minimum as a one-year trial. See the grant guide and the full cost guide for details.
Living with a nitrogen-reducing system
Day to day, a nitrogen-reducing system works much like the septic system you have now. You flush, run the dishwasher and do laundry as usual. A few habits help it work well and last longer:
- Keep the service visits your operating permit or contract calls for, and keep the reports.
- Never turn off the power to an aerobic unit to save on electricity. The bacteria need air to remove nitrogen.
- Answer alarms right away. Most alarm calls are simple fixes when they are caught early.
- Keep wipes, grease and harsh chemicals out of the drains, just as with any septic system.
Why upgrade before the 2030 rush?
Thousands of septic systems around the lagoon fall under this law, and the number of licensed contractors is limited. As 2030 gets closer, wait times for site visits, permits and installs are likely to grow. Getting on the schedule early gives you more choice of contractor, more time to use grant funds while they are available, and less stress if your old system fails first.
It also helps if you plan to sell. Buyers on the island are learning about the 2030 rule, and a home that already has a compliant system is easier to sell.