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Types of Septic Systems Approved in Alabama

If you're building a new home or replacing an existing septic system in Alabama, understanding which system types are approved by the Alabama Department of Public Health (ADPH) and the Alabama Department of Environmental Management (ADEM) is essential.

State-Approved Septic System Types

1. Conventional Septic Systems

The standard three-part system consisting of a septic tank and drain field. Most common in Mobile County where soil conditions permit. Includes:

• Concrete, polyethylene, or fiberglass tank
• Distribution box
• Drain field trenches
• Soil absorption area

2. Engineered Septic Systems

Required for challenging sites in Mobile County with poor soil conditions, high water tables, or small lot sizes. These systems are custom-designed by licensed engineers.

3. Advanced Treatment Systems (ATS)

Secondary-treatment-level systems required in environmentally sensitive areas. Provides higher treatment quality before discharge.

Approved Tank Materials

• Concrete: Durable, heavy, long-lasting
• Polyethylene (Poly): Lightweight, corrosion-resistant, easy to install
• Fiberglass: Strong, lightweight, resistant to chemicals

Mobile County-Specific Requirements

Before any septic system installation in Mobile County, a percolation test must be performed by a licensed professional. Results determine which system type your property can support.

Regulatory Bodies in Alabama

• ADPH - Primary regulator for onsite sewage systems (Chapter 420-3-1)
• ADEM - Environmental permitting for larger systems
• Mobile County Health Department - Local enforcement
• Alabama Onsite Wastewater Board (AOWB) - Licensing