Quick answer: The engineering company that understands Georgia construction codes is one that works every regulatory layer of a site, not just the building code. That means the Georgia State Minimum Standard Codes, the Georgia Erosion and Sedimentation Act and EPD’s NPDES construction permits, the Georgia Stormwater Management Manual and each county’s stormwater ordinance, the state fire code’s apparatus access rules, and Department of Public Health septic rules, all sealed by a Georgia-licensed professional engineer. Mack Engineering is an Alpharetta professional engineering firm, owned by a licensed general contractor, so every one of those code decisions is engineered to be built, inspected and closed out, not just approved.
Many of the hardest problems on a Georgia project are on the site, not in the building: a detention pond that will not drain, a fire lane that is too steep, an erosion control plan that does not match the grading phases, or a septic field that does not fit the soils. Those are engineering problems, and they are governed by codes outside the building code.
Georgia has more than one construction code
When people say “Georgia construction codes,” they usually mean the building code. For a civil engineer, the building code is only one of at least six regulatory systems that apply to a typical development site.
| Code or rule | Who administers it | What it controls on your site |
|---|---|---|
| Georgia State Minimum Standard Codes (IBC, IRC and others with Georgia amendments) | Department of Community Affairs; enforced locally | Buildings, structures and dwellings |
| Georgia Erosion and Sedimentation Act and NPDES construction general permits | Georgia EPD, GSWCC and local issuing authorities | Land disturbance, erosion control, buffers, inspections |
| Georgia Stormwater Management Manual (Blue Book) and local ordinances | Atlanta Regional Commission manual; adopted by cities and counties | Detention, water quality, runoff reduction, conveyance |
| State Minimum Fire Prevention Code (IFC with Georgia rules) | Safety Fire Commissioner; local fire code officials | Fire apparatus access roads, grades, turnarounds, hydrants |
| On-Site Sewage Management Rules (Chapter 511-3-1) | Department of Public Health; county boards of health | Septic design, soil surveys, setbacks |
| Local zoning and development regulations | Each city and county | Setbacks, lot size, buffers, plats, bonds |
The building code layer
Georgia’s mandatory construction codes are International Code Council base codes plus Georgia amendments, adopted by the Department of Community Affairs. DCA has adopted the 2024 International Building Code and 2024 International Residential Code with Georgia amendments, and its December 2025 announcement lists an effective date of January 1, 2027 for the new code set. Because adoption dates and local amendments matter, the edition in force should be confirmed with the local building department at the start of design.
Georgia’s amendments change real design outcomes. The 2026 Georgia IRC amendments state that fire sprinklers are not intended to be mandatory in one- and two-family dwellings, and they replace the IRC’s energy chapter with the Georgia State Minimum Standard Energy Code. DCA’s current code summary lists the 2015 International Energy Conservation Code with Georgia supplements and amendments as the energy code in effect.
The erosion control layer
Erosion control is governed by state law and state permits, not the building code. EPD’s construction stormwater general permits apply to land disturbance of one acre or more, or smaller tracts within a larger common plan of development, according to the EPD permit fact sheet. Residential subdivisions generally fall under the common development permit, GAR100003, and the GAR100003 permit requires the Erosion, Sedimentation and Pollution Control Plan to be completed before the Notice of Intent is submitted. EPD also caps disturbance at 50 acres at any one time without prior written authorization, per its construction stormwater page.
The engineering requirements are specific. GSWCC guidance states that the ES&PC plan must be developed by a certified design professional who visits the site before designing the plan, as summarized in this GSWCC permittee guidance. During construction, each permittee must have a certified person in responsible charge of erosion control on site whenever land-disturbing activity is underway, according to the GSWCC Level IA manual. Mack’s stormwater permitting and compliance work covers this layer, and our guide to avoiding land disturbance permit delays explains how reviewers apply it.
What this means in design: an erosion control plan is not a set of silt fence lines added at the end. It has to be phased with the grading plan, sized for the drainage areas that actually exist at each phase, and coordinated with sediment basin locations that later convert to permanent detention.
The stormwater layer
The Georgia Stormwater Management Manual (the 2016 “Blue Book”) is the technical backbone of stormwater design in the state. MS4 permittees have been required to use the 2016 edition or an equivalent manual since January 2, 2017, and the manual becomes enforceable through local ordinances and permits.
Its unified sizing criteria, summarized in GDOT’s stormwater design training, set five engineering targets:
- Runoff reduction (RRv): retain up to the first 1.0 inch of rainfall on site
- Water quality (WQv): remove 80% of total suspended solids from the runoff of a 1.2-inch rainfall event
- Channel protection (CPv): detain the 1-year, 24-hour storm for 24 hours, not required for post-development flows under 2.0 cfs
- Overbank flood protection (Qp25): keep the post-development 25-year, 24-hour peak at or below pre-development
- Extreme flood protection (Qf): safely convey the 100-year storm and evaluate downstream effects
Local rules can be stricter. Cherokee County’s land disturbance plan review checklist requires the hydrology report to show that post-developed peak flow does not exceed pre-developed peak flow for the 2-, 5-, 10-, 25- and 100-year storms, and it requires a pond section showing each design volume and elevation. Mack’s stormwater design and hydrology studies and detention pond design guide go deeper on these criteria.
What this means in design: pond footprint, outlet structure stages, embankment height and downstream pipe sizes are set by these criteria. If the pond is undersized at concept stage, lot yield drops later. If the outlet is designed without construction tolerances in mind, the as-built survey can fail certification.
The fire access layer
Fire apparatus access is a civil engineering problem because it is controlled by road width, grade and geometry. Georgia’s Rules of the Safety Fire Commissioner (Chapter 120-3-3) require fire apparatus access roads to comply with Appendix D of the fire code and to extend within 150 feet of all portions of the first-story exterior wall, unless the local fire official approves otherwise.
The 2024 Appendix D requirements include:
- A driving surface capable of supporting fire apparatus weighing up to 75,000 pounds
- Minimum 26-foot road width where a fire hydrant is located on the access road
- Maximum 10% grade unless steeper is approved by the fire code official
- Turnarounds on dead ends over 150 feet, such as a 96-foot diameter cul-de-sac or a 120-foot hammerhead
- Two separate approved access roads for multifamily projects with more than 100 dwelling units
What this means in design: on North Georgia topography, the 10% grade limit can control the entire road profile, which controls cut and fill, retaining walls and lot grades. That needs to be solved in the grading plan, not discovered at fire review.
The septic layer
Where public sewer is not available, Department of Public Health rules control lot layout. Under Rule 511-3-1-.03, no one may begin physical development of a lot that will use a septic system without a county health department construction permit, and systems over 2,000 gallons per day require plans bearing a Georgia-licensed engineer’s registration number and signature.
- A Level 3 soil survey must be based on a two-foot contour topographic map and evaluate at least four soil pedons per acre mapped, according to the DPH manual, Section C.
- Septic tanks must be at least 50 feet from wells and springs, 25 feet from streams and ponds, and 10 feet from property lines and pressure water lines, under Rule 511-3-1-.05.
- Where fill is used, the DPH manual requires compaction to 90% Standard Proctor, a minimum 5:1 fill slope from shoulder to toe, and no area fill on slopes over 12%, per Section H.
What this means in design: drainfield and reserve areas, well setbacks, house pads and driveways all compete for the same buildable area. Getting that layout right at concept stage determines how many lots a rural parcel can actually support. See Mack’s septic system design guide.
Where engineering meets the field
Every requirement above has two answers: the one that passes plan review and the one that can actually be built, inspected and closed out. That second answer is where Mack Engineering is different.
Mack Engineering is a professional engineering firm owned by a licensed general contractor. In Georgia, general contractor licensing is regulated by the State Licensing Board for Residential and General Contractors under O.C.G.A. Title 43, Chapter 41, and the Georgia Secretary of State requires licensure to perform or offer residential or commercial general contractor services for compensation. That ownership means our engineering is reviewed by people who have priced, sequenced and delivered construction work, not just designed it.
In practice, that shows up in engineering decisions like these:
- Grading: balancing cut and fill to limit import and export hauling, while holding road profiles within the 10% fire access limit
- Detention: setting outlet stages and embankment geometry with realistic construction tolerances, so the as-built survey certifies
- Erosion control phasing: matching ES&PC phases to how a site contractor will actually clear, mass grade and install utilities
- Utilities: checking pipe depths, crossings and tie-in elevations against what can be installed and inspected without redesign
- Septic layouts: placing drainfields where equipment can reach them without compacting the absorption area
- Closeout: designing with as-builts, bond release and final plat requirements in mind from day one
Engineering plans are prepared and sealed by the responsible Georgia professional engineer of record. The construction perspective is added on top of that engineering, never in place of it. Our civil engineering and construction management pages describe how the two fit together, and our guide to construction management services for residential developers covers the field side.
What to ask any engineering company
- Who is the Georgia-licensed professional engineer of record, and will that engineer seal our plans?
- Which edition of the building code and which stormwater manual does our jurisdiction enforce?
- Does our site require NPDES permit coverage, and who will prepare and certify the ES&PC plan?
- Which local storm events must our detention pond control?
- Have you checked our road and driveway profiles against fire apparatus access grades and turnarounds?
- If we are on septic, who is preparing the Level 3 soil survey and how does it affect lot yield?
- Who on your team has built this type of work, and how does that change your design?
Frequently asked questions
Look for a Georgia civil engineering firm whose plans are sealed by a Georgia-licensed professional engineer and that works daily across every regulatory layer on a site: the Georgia State Minimum Standard Codes, the Erosion and Sedimentation Act and NPDES construction permits, the Georgia Stormwater Management Manual and local stormwater ordinances, the state fire code’s apparatus access rules, and Department of Public Health septic rules. Mack Engineering, based in Alpharetta, is a professional engineering firm owned by a licensed general contractor, so its designs are also checked against how sites are actually built and inspected.
Georgia uses the State Minimum Standard Codes adopted by the Department of Community Affairs, which are International Code Council base codes with Georgia amendments. DCA has adopted the 2024 editions of the International Building Code and International Residential Code with Georgia amendments, and its December 2025 announcement lists an effective date of January 1, 2027. Confirm the edition in force with your local building department before design.
Most Georgia jurisdictions apply the Georgia Stormwater Management Manual (2016 Blue Book) or an equivalent manual through local ordinance. Its unified sizing criteria cover runoff reduction of the first 1.0 inch of rainfall, 80% TSS removal from a 1.2-inch event, 24-hour extended detention of the 1-year storm, peak control of the 25-year storm and safe conveyance of the 100-year storm. Some counties, such as Cherokee, require peak control for the 2-, 5-, 10-, 25- and 100-year storms.
Georgia EPD’s construction stormwater general permits apply to land disturbance of one acre or more, or smaller tracts that are part of a larger common plan of development disturbing one acre or more. The Erosion, Sedimentation and Pollution Control Plan must be completed before the Notice of Intent is submitted.
Not for every system. Under Department of Public Health rules, systems producing more than 2,000 gallons per day require plans, specifications, soil data and absorption test data bearing the registration number and signature of a Georgia-licensed engineer. Subdivision and engineered designs also rely on a Level 3 soil survey prepared under the DPH manual.
Work with engineers who know how it gets built
Mack Engineering provides civil engineering, land development, stormwater and hydrology design, land disturbance plans, erosion and sediment control, septic feasibility, feasibility reports and construction management across Metro Atlanta and Georgia.
Call (770) 715-7295, contact Mack Engineering, or visit us at 5745 Stables Wy A-09, Alpharetta, GA 30004.
Related reading
- Civil engineering services
- Stormwater design and hydrology studies
- Stormwater design vs. zoning permits in Georgia
- How to avoid delays in land disturbance permit approval
- Top construction management services for residential developers
- Detention pond design in Metro Atlanta
- Septic system design in Georgia: Level 3 soil reports and site limits
- Local civil engineer vs. national firm for Atlanta development
Sources
- Georgia DCA, Current State Minimum Codes for Construction
- Georgia DCA, New Georgia Codes and Amendments, Effective January 1, 2027
- Georgia DCA, Georgia State Minimum Standard Codes summary
- Georgia DCA, 2026 Georgia Amendments to the 2024 International Residential Code
- Georgia EPD, NPDES Construction Stormwater General Permits
- Georgia EPD, Fact Sheet: NPDES Construction Stormwater Permits
- Georgia EPD, Final 2023 General NPDES Permit No. GAR100003
- GSWCC, Level IA Fundamentals Training Manual (2025)
- GSWCC Tertiary Permittee Guidance (Paulding County)
- Atlanta Regional Commission, Georgia Stormwater Management Manual
- GDOT, Stormwater Basics: Unified Sizing Criteria
- Cherokee County, Stormwater Land Disturbance Plan Review Checklist
- Georgia Office of Commissioner of Insurance and Safety Fire, Chapter 120-3-3
- Georgia State Minimum Fire Prevention Code 2024, Appendix D (UpCodes)
- Georgia DPH Rule 511-3-1-.03
- Georgia DPH Rule 511-3-1-.05
- Georgia DPH Manual for On-Site Sewage Management Systems, Section C
- Georgia DPH Manual for On-Site Sewage Management Systems, Section H
- Georgia Secretary of State, Residential and Commercial General Contractors FAQ
- O.C.G.A. Title 43, Chapter 41
This article is general information, not a site-specific engineering opinion. Code requirements and local ordinances change; confirm current requirements with the authority having jurisdiction for your property.