ATU Maintenance in Florida: What You're Required to Do (and Why It Matters)

If your home has an aerobic treatment unit (ATU) — sometimes called an aerobic septic system — you have additional maintenance obligations under Florida law that most homeowners don't fully understand. Skipping them can mean fines, system failure, and a very expensive repair bill.

What Is an ATU?

An aerobic treatment unit is a more advanced type of septic system that uses oxygen to break down wastewater more thoroughly than a conventional septic tank. Instead of slow anaerobic decomposition in a buried tank, an ATU injects air into the treatment chamber, supporting aerobic bacteria that digest waste much faster and more completely.

The treated effluent from an ATU is clean enough to be dispersed via spray heads in your yard — which is why many ATU homes have a sprinkler-like system in a designated area of the lawn. This dispersal method is called a spray field or drip irrigation dispersal.

ATUs are common in Florida on lots where conventional drainfields can't be installed — typically because the lot is too small, the soil doesn't perc properly, or the water table is too high for a standard system to work.

Florida Law: Annual ATU Inspection Is Mandatory

Under Chapter 64E-6, Florida Administrative Code, homeowners with aerobic treatment units are required by law to have their system inspected by a licensed septic contractor at least once per year. After the inspection, the contractor must submit a service report to the county health department.

ATU owners are also required to maintain an annual operating permit issued by the county health department. The permit is renewed each year and is tied to your system's compliance with state standards.

What an ATU Maintenance Visit Includes

A thorough ATU inspection covers:

• Air pump inspection — The air pump is the heart of an ATU. It aerates the treatment chamber and is the most common component to fail. We check it for proper operation and signs of wear.
• Chlorine disinfection check — ATUs that spray effluent must disinfect with chlorine tablets before dispersal. We check tablet levels and the chlorine contact chamber.
• Spray head inspection — Each spray head is checked for clogs, breakage, and proper coverage. Broken spray heads are a common DEP violation.
• Control panel check — We inspect the control panel for alarms, floats, and proper function of all circuits.
• Tank solids check — We check sludge and scum levels in the treatment and settling compartments. High solids can carry over into spray heads and cause failures.
• Effluent quality assessment — We visually assess the quality of treated effluent before dispersal.
• Service report submission — We file the required inspection report with the county health department on your behalf.

Most Common ATU Problems We Find

After years of ATU maintenance calls across the Treasure Coast, these are the problems we see most often:

What Happens If You Skip ATU Maintenance?

The consequences of ignoring ATU maintenance in Florida are significant:

• The county health department issues a Notice of Violation
• You're required to bring the system into compliance at your own expense, on a deadline
• Continued non-compliance can result in civil fines
• In extreme cases, the county can require you to replace the entire ATU system
• An unmaintained ATU that sprays partially treated effluent creates health and environmental hazards — and potential personal liability

Frequently Asked Questions