The Governing Framework

Georgia regulates onsite sewage under a state-rule-plus-county-permit structure:

• Georgia Rules Chapter 511-3-1 — On-Site Sewage Management Systems (effective January 1, 2016).
• Georgia Department of Public Health (DPH), Environmental Health Section — writes and interprets the rules statewide.
• County Environmental Health Offices — 159 counties each administer permits and conduct inspections, under DPH oversight.
• DPH On-Site Sewage Management Systems Manual — the technical design manual that accompanies the rules.

Septic Tank Capacity — Rule 511-3-1-.05

Georgia uses a straightforward bedroom-based capacity rule with a distinctive 1,000-gallon floor:

Garbage Disposal Upsize Rule

Georgia requires a 50% increase in septic tank capacity if the home has a garbage disposal installed. For a 4-bedroom home with a disposal:

• Base capacity without disposal: 1,000 gallons
• With disposal: 1,500 gallons (1,000 × 1.50)

This is more conservative than many states. Georgia's rationale is that disposals dramatically increase the solids loading on the tank, which shortens the practical retention time and overwhelms the biological digestion unless the tank is significantly larger.

Gray Water Bonus Capacity

If the development includes a gray water reuse system (e.g., reclaimed water for landscape irrigation), Georgia rules add a capacity bonus to the septic tank for each bedroom over 4:

A 6-bedroom home with gray water reuse: 1,000 base + 2×250 (bedrooms 5 & 6) + 2×130 (gray water bonus for bedrooms 5 & 6) = 1,760 gallons minimum.

Permit Process — County Environmental Health

1. Contact your county environmental health office. All 159 Georgia counties administer OSSF permits at the local level.
2. Site evaluation. A county EH specialist or approved private provider conducts the soil evaluation. Depending on county, this may be a percolation test or soil profile assessment.
3. Design submittal. Plot plan showing tank, dispersal field, setbacks, and any gray water components. Many rural counties will approve a standard installer-submitted plan without additional engineering.
4. Permit issuance. Typical county fee $250–$500. Timeline 1–4 weeks in most counties.
5. Installation. By a Georgia-certified installer.
6. Final inspection. County EH inspects tank, dispersal, and outlet before backfill.

Non-Conventional System Rules — 511-3-1-.18

For properties where conventional gravity-flow dispersal isn't feasible, Georgia has a separate rule (511-3-1-.18) covering non-conventional systems: low-pressure pipe, mound systems, drip dispersal, and advanced treatment units. These installations typically require:

• A professional engineer's design.
• A maintenance contract with a state-approved maintenance provider.
• Higher permit fees ($500–$1,500).
• Periodic operational inspection by the maintenance provider.

Material Approvals

Georgia accepts polyethylene septic tanks that meet the Chapter 511-3-1 construction standards. All major rotomolded HDPE manufacturers (Norwesco, Snyder, Enduraplas, Chem-Tainer) have approved models on Georgia DPH's list. Key verifications at order:

• Tank model appears on the current DPH approval list.
• IAPMO or NSF listing visible on the tank.
• ASTM D1998 compliance for polyethylene wall construction.
• Effluent filter certified to NSF 46 where required by county.

Georgia-Specific Considerations

• Atlanta metro counties. Fulton, DeKalb, Cobb, Gwinnett, Clayton — high permit volume with established turnaround. Generally 2–4 weeks.
• Coastal counties. Chatham, McIntosh, Glynn, Camden — high groundwater and hurricane-zone flood rules layered on top of the state-level requirements. Anti-buoyancy anchoring and elevated risers are common requirements.
• Piedmont granitic soils. The central Piedmont belt has soils that are fast-percolating in the surface layer but slow-percolating in the saprolite (weathered bedrock) below. Site evaluation may require deeper soil borings than elsewhere.
• Agricultural zones. South Georgia farm regions have sandy soils that generally perc well and support standard-design septic systems.

Frequently Asked Questions

Do I need to install a 1,500-gallon tank if I have a garbage disposal?

Yes for a 4-bedroom or larger home. Georgia's 50% upsize rule means a 4-BR home with disposal needs 1,500 gallons (vs 1,000 without). For 1-3 BR homes with disposal, the 50% upsize takes you to 1,500 gallons as well. Plan for this at permit time.

Why is the capacity flat at 1,000 gallons for 1-4 bedrooms?

Georgia's design daily flow assumptions for residential use produce similar total flows in the 1-4 bedroom range under average occupancy. The 250-gallon step per bedroom kicks in above 4 because high-occupancy homes show measurably higher water use.

Is the gray water bonus an addition to the septic tank or a separate tank?

It's additional capacity in the septic tank system to handle the slightly higher flow that gray water reuse systems can generate. Most installers meet the bonus via a larger single tank; some use a two-tank series configuration.

Do I need an Authorized On-Site Wastewater Evaluator like North Carolina uses?

No — Georgia uses a county-EH model rather than a private-AOWE model. All permits go through county environmental health offices, though private soil classifiers may perform the soil evaluation portion in some counties.

What about coastal sewage rules?

Coastal Georgia counties (Chatham, Glynn, etc.) add flood-zone and groundwater requirements on top of Chapter 511-3-1 rules. Anti-buoyancy anchoring, elevated access risers, and sometimes advanced treatment. Check with your coastal county EH office.

Source Citations

• Georgia R&R Subject 511-3-1 — On-Site Sewage Management Systems (full rules)
• Rule 511-3-1-.05 — Septic Tanks (direct link)
• Rule 511-3-1-.18 — Non-Conventional On-Site Sewage Management Systems
• Georgia DPH Environmental Health — Onsite Sewage
• Manual for On-Site Sewage Management Systems (PDF)
• A Homeowner's Guide to On-Site Sewage (PDF)