The Governing Framework — Mid-Transition

Florida is in the middle of a multi-year jurisdictional transfer of its septic-system regulatory program. Until 2021, the Florida Department of Health (DOH) administered onsite sewage rules under Chapter 64E-6 Florida Administrative Code (FAC). Effective July 1, 2021, regulatory authority transferred to the Florida Department of Environmental Protection (DEP), which is replacing 64E-6 with Chapter 62-6 FAC. The transition is being implemented in phases:

The Governing Statute — FS §381.0065

The state statute authorizing the program is Florida Statutes Section 381.0065 — "Onsite Sewage Treatment and Disposal Systems; Regulation." This is the law that the FAC rules implement. Key statutory requirements that carry through both 64E-6 and 62-6:

• Permit required before installation, substantial modification, or abandonment of any OSTDS.
• Minimum tank design and capacity standards set by administrative rule.
• Outlet filter device required on all permitted tanks.
• Minimum setbacks from potable water wells, surface waters, and property lines.
• Local county health departments (DOH counties) or DEP regional offices (DEP counties) administer permits and inspections.

Septic Tank Capacity — The Multi-Chamber & Filter Rules

Florida has two distinctive tank-design requirements that go beyond what most states demand:

1. Multi-chamber or tanks-in-series. All permitted septic tanks must be multi-chambered (typically 2 compartments) OR be installed as multiple tanks in series. Single-compartment tanks are not permitted for new installations.
2. Outlet filter device. An approved outlet filter (a solids screen in the outlet tee) is required on every permitted tank. This captures floating solids that would otherwise escape to the dispersal field, dramatically extending dispersal-field lifespan in Florida's high-groundwater environment.

The minimum capacity for single-family residences scales with effective dwelling units (EDUs):

These are the practical floor numbers most Florida counties enforce under 64E-6 / 62-6. Verify with your specific county because some coastal counties impose higher minimums in high-groundwater zones.

High Groundwater & Hurricane Considerations

Florida's water-table conditions shape every OSTDS installation. Standard national-default septic designs don't work in Florida, which is why the state rules include supplemental requirements not found in most other states:

• Mounded dispersal systems are common in south and coastal Florida where groundwater is within 42 inches of grade. Gravity-flow conventional drainfields are rare outside the Panhandle and central ridge.
• Anti-buoyancy anchoring is required for tanks installed in areas where groundwater can rise above the tank's invert. This is essentially everywhere south of I-4 and along the coasts. A 1,000-gallon tank holding air weighs <500 lb; it will float out of the ground under hurricane-rain groundwater conditions unless anchored.
• Flood-zone filings are required for tanks in FEMA Special Flood Hazard Areas. The tank and its vent must be elevated or sealed per FEMA rules, and the dispersal field design accounts for flood-event surcharge.
• Post-hurricane inspection is implied by the operating permit. After a named storm, Florida health departments may issue local guidance to inspect and pump tanks that floated or were inundated.

Material Approvals

Florida accepts polyethylene septic tanks that meet either Chapter 64E-6 or Chapter 62-6 design standards, including:

• IAPMO listing for uniform plumbing code compliance.
• ASTM D1998 wall-thickness and material standards for upright polyethylene storage tanks.
• State-approved outlet filter device installed at the outlet tee.
• Manufacturer's certification of load ratings for buried installations (particularly relevant for traffic-bearing installations under driveways or parking).

Norwesco, Snyder, Enduraplas, and Chem-Tainer all produce rotomolded HDPE tanks compliant with Florida OSTDS rules. Order the Florida-specific configuration when buying — it ships with anchor straps, proper manway, and outlet filter pre-installed.

Frequently Asked Questions

How do I know if my county is under DOH or DEP?

Call your county environmental health office. DOH counties file through the Department of Health; DEP counties file through the DEP regional office. The fees and paperwork differ; engineering requirements are similar.

Can I install a single-compartment tank?

No. Florida requires multi-chamber tanks or tanks-in-series for all permitted installations. Even single-compartment replacements of existing tanks must upgrade to multi-chamber on re-permit.

What's an outlet filter and why do I need it?

An outlet filter is a solids screen in the tank outlet tee that captures floating solids (grease, paper, undigested waste) before they escape into the dispersal field. Florida requires one on every permitted tank because the state's high-groundwater dispersal fields have much less margin than elsewhere. Filter maintenance (cleaning every 1-3 years) is the owner's responsibility.

Does Florida require a polyethylene tank or will concrete work?

Both are accepted. Concrete is traditional in Florida and remains common. Polyethylene is increasingly popular because it's easier to install, resists the state's aggressive groundwater better, and ships with integrated anchor points. Cost is comparable for mid-size residential tanks.

Do I need flood insurance if I have a septic tank in a flood zone?

Flood insurance covers the dwelling and sometimes ancillary structures. OSTDS components (tank, dispersal) are typically NOT covered by standard flood insurance. Speak with your insurance agent about septic-system-specific endorsements. Hurricane damage to a tank is a known loss profile in Florida.

Source Citations

• Florida Statute §381.0065 — Onsite Sewage Treatment and Disposal Systems; Regulation
• Chapter 62-6 FAC (current DEP rule) — flrules.org
• Chapter 64E-6 FAC (historical DOH rule) — flrules.org
• Florida DEP — Onsite Sewage Program
• Chapter 64E-6 FAC full text (PDF, Florida Health)
• DEP — Onsite Sewage Program News & Rulemaking