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COMMERCIAL SEPTIC INSTALLATION · METRO ATLANTA
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or call (678) 863-5620The short answer
A commercial septic system in Georgia is sized from the DPH Manual's Table 13.J flow schedule by seats, people, rooms or floor area, then permitted by the county Environmental Health office after a soil evaluation. Flows over 2,000 gallons per day need engineer-sealed plans, and the county inspects everything before it is covered.
Reviewed by Atlanta Water & Sewage Solutions · Last updated
Who does the work
One crew, the whole line
Key facts
Each row links to the agency, code or publisher it comes from. Tap a source to check it yourself.
| Topic | What it says | Source |
|---|---|---|
| Who permits it | The County Board of Health (Environmental Health) issues the construction permit and inspects before cover (511-3-1-.03) | Georgia DPH Rules Chapter 511-3-1, On-Site Sewage Management Systems (Jan 2016), 2016 |
| How flow is set | DPH Manual Table 13.J, on peak flow, never long-term averages (511-3-1-.13) | Georgia DPH Manual for On-Site Sewage Management Systems (March 2026) — Section J, Table 13.J Sewage Flow Schedule, 2026 |
| Medical office | 200 gallons per day per exam room | Georgia DPH Manual for On-Site Sewage Management Systems (March 2026) — Section J, Table 13.J Sewage Flow Schedule, 2026 |
| Hotel or motel, no kitchenette | 100 gallons per day per room (150 with a kitchenette) | Georgia DPH Manual for On-Site Sewage Management Systems (March 2026) — Section J, Table 13.J Sewage Flow Schedule, 2026 |
| Grocery store | 200 gallons per day per 1,000 ft² of floor space, plus any food-service seats | Georgia DPH Manual for On-Site Sewage Management Systems (March 2026) — Section J, Table 13.J Sewage Flow Schedule, 2026 |
| Beauty salon | 150 gallons per day per chair, plus 20 per employee | Georgia DPH Manual for On-Site Sewage Management Systems (March 2026) — Section J, Table 13.J Sewage Flow Schedule, 2026 |
| Engineer threshold | Flow in excess of 2,000 gallons per day: plans and soil data sealed by a Georgia-registered engineer (511-3-1-.03(6)) | Georgia DPH Rules Chapter 511-3-1, On-Site Sewage Management Systems (Jan 2016), 2016 |
| Installer certification | A commercial certification is required to install systems designed for 2,000 gpd or more (Manual Section N) | Georgia DPH Manual for On-Site Sewage Management Systems (March 2026) — Section N Certification, 2026 |
| Dosing tank trigger | Required on a conventional system needing more than 500 linear feet of absorption trench | Georgia DPH Manual for On-Site Sewage Management Systems (March 2026) — Section F Dispersal Systems, Table 9.F and dosing tanks, 2026 |
| New commercial permit fee | $600 in Newton, Rockdale and Gwinnett (GNR); Walton inspections $550 (1–1,000 gpd) or $850 (1,001–2,000 gpd) | GNR Environmental Health Fee Schedule — Newton County (effective Jan 1, 2026), 2026 |
Plain definitions
The whole story
Every commercial design starts with one multiplication: the facility's unit count times its gallons per day from Table 13.J of the DPH Manual. The table is long, covering airports to veterinary offices, and it is blunt. It does not care that the office is quiet on Fridays or that the store is slow in January. Rule 511-3-1-.13 tells the health department to size on peak flow.
Here is how the arithmetic plays out for building types we get asked about, worked straight from the table and shown for scale only. A medical practice with six exam rooms comes to 1,200 gallons per day at 200 per room. A 20-room motel without kitchenettes lands at exactly 2,000. A shop with 30 workers and no showers is 750, and adding a break-room kitchen puts it at 900 because the table adds 5 gallons per worker. A strip of retail with 12,000 square feet of enclosed space is 1,200 at 100 per thousand square feet.
Mixed uses stack. The Manual's own note gives the case of a grocery store that also serves food: 200 gallons per thousand square feet of floor plus 50 per seat. A 10,000-square-foot market with a 20-seat deli therefore needs 2,000 plus 1,000, or 3,000 gallons per day, which moves the project into engineered design. A church with a weekday preschool, or a salon that shares a building with a dental office, is added up the same way.
The permit, not this page, sets your final design flow. An owner can also submit metered water records from an identical or similar operation, and the health department may weigh them, but it will not approve a design built on averages.
Worth knowing
Two separate rules meet at 2,000 gallons per day, and they are worded differently. Rule 511-3-1-.03(6) requires plans, specifications, soil data and absorption test data sealed by a Georgia-registered professional engineer when the flow is in excess of 2,000 gallons per day. At or below that figure, the county may accept plans from anyone it considers knowledgeable in system design.
The Manual's certification section draws its line at 2,000 gallons per day or more: the contractor who installs a system designed for that flow needs a commercial certification on top of the basic installer module. So the 20-room motel above, at exactly 2,000, may not need sealed plans but does need a commercially certified installer. Ask any contractor bidding a large system to show where that certification appears on the DPH list.
In practice, crossing the line adds an engineer's design fee and review time to the schedule, and often a more detailed site plan. It is worth knowing before a building is designed, because a few seats, rooms or exam rooms can decide which side of it a project falls on.
Two separate rules meet at 2,000 gallons per day, and they are worded differently.
Worth knowing
For non-residential systems the Manual converts flow into trench with a formula in Section F: the percolation coefficient for the site's soil times the gallons per day gives the square feet of trench bottom, and dividing by the trench width gives linear feet. The coefficient comes from Table 9.F and rises as the soil gets slower.
An illustration: soil that percolates at 45 minutes per inch has a coefficient of 1.342. The six-exam-room medical office at 1,200 gallons per day would need about 1,610 square feet of trench bottom, which is roughly 805 linear feet if the design used a two-foot trench. That single number explains a lot about commercial sites. It is past the 500-foot mark where the Manual requires a dosing tank, so the system gains a pump, floats, controls and an alarm.
Clay makes it longer. Much of the east metro sits on Cecil and similar Piedmont soils, which the USDA describes as deep, well-drained red clay subsoil. A slower perc rate pushes the coefficient up and the trench out, and the replacement area has to fit on the lot as well. Check your parcel's mapped soils on the Web Soil Survey as a first look; the permit relies on the soil classifier's report.
Soil & terrain
Parking lots, drive aisles, dumpster pads and future building pads compete with the drain field for the same ground. The field cannot sit under pavement or traffic, and the Manual's lot-sizing criteria expect an equal-sized, unobstructed replacement area on top of the initial field.
The same criteria cap daily flow at 600 gallons per acre on a private well and 1,200 per acre on public water, and grow the minimum lot size in proportion when a building exceeds that. Walton County adopted those caps into a county ordinance. A 3,000 gpd building on public water therefore needs at least two and a half acres under the recommended criteria, before setbacks and slopes are subtracted.
Your options
OPTION 01
When it fits: Domestic-strength waste, enough suitable soil and room for the field plus the replacement area.
OPTION 02
When it fits: Kitchens, food prep or other waste above 200 mg/L BOD5 and TSS.
OPTION 03
When it fits: Sites where a higher level of treatment is needed before dispersal.
Per the Manual's Section D, ATU standards are written for domestic-strength waste; non-residential units get separate review.
OPTION 04
When it fits: Shallow, slow or limited soils where a trench field will not fit.
How the job runs
Seats, rooms, exam rooms, workers, floor area, kitchens and hours: everything Table 13.J needs to set a peak design flow. Call (678) 863-5620 to set up the free site visit.
Walk the lot for the field and replacement area, away from paving, parking and planned additions, and pull the mapped soils.
A certified soil classifier evaluates the site. GNR counties have required a Level 3 soil report for septic permits since February 7, 2022.
GNR Public Health — Septic Systems (Gwinnett, Newton & Rockdale)
Tank, pretreatment, dosing and field sized from the flow and the percolation coefficient; sealed by an engineer when flow exceeds 2,000 gpd.
511-3-1-.03(6); Manual Section FGeorgia DPH Rules Chapter 511-3-1, On-Site Sewage Management Systems (Jan 2016)
The county Environmental Health office reviews and issues the permit, which is valid for up to 12 months. We handle the application with the office.
511-3-1-.03Georgia DPH Rules Chapter 511-3-1, On-Site Sewage Management Systems (Jan 2016)
Tanks set level, pretreatment and dosing chambers plumbed, field lines built to the approved length and grade. We are on Georgia DPH's certified installer list.
Georgia DPH Certified Septic Tank Installers list (9/18/2026)
No system may be covered or used until the county's final inspection and written approval.
511-3-1-.03(4)Georgia DPH Rules Chapter 511-3-1, On-Site Sewage Management Systems (Jan 2016)
Backfill, final grade and a pump and alarm test, plus a plain-language rundown of what the system needs as the building fills up.
Permits & the Georgia rules
Calculate peak design flow from Table 13.J, adding flows for every use in the building.↗
Obtain the soil evaluation the county requires (Level 3 in GNR counties).↗
Submit the permit application with the site plan and, above 2,000 gpd, engineer-sealed plans and soil data.↗
Show pretreatment for any waste stream above 200 mg/L BOD5 and TSS.↗
Install under the permit and call for inspection before anything is backfilled.↗
Georgia rule 511-3-1-.13
“Calculations will be made on the basis of peak flow and not on long term averages.”
Georgia rule 511-3-1-.03(6)
“If a proposed on-site sewage management system will produce a sewage flow in excess of two thousand gallons per day”
Georgia rule Manual Section N
“A commercial certification is required for contractors installing a system designed for a flow of 2,000 gallons per day or more.”
Newton, Rockdale and Gwinnett (GNR Public Health)
Commercial site evaluation, permit and initial inspection: $600. Gwinnett's schedule bills work installed without a permit at twice the permit fee.↗
Walton County (Northeast Health District)
New commercial inspections are $550 for 1–1,000 gpd and $850 for 1,001–2,000 gpd; the county lot-size ordinance limits flow per acre.↗
Morgan and Jasper (Northeast Health District)
Permits run through the district's county Environmental Health offices; check the district's septic page for the current forms.↗
Commercial installation permits are $400 under 2,000 GPD and $600 above it, and DeKalb Public Health reviews new commercial plans.↗
What it costs
Chamber system, residential scale (Georgia)
$7,000–$12,000
per system
Typical market range — Septic & Well Pro — Septic Installation Cost Georgia 2026 (updated June 9, 2026), 2026
Drip dispersal system, residential scale (Georgia)
$8,000–$18,000
per system
Typical market range — Septic & Well Pro — Septic Installation Cost Georgia 2026 (updated June 9, 2026), 2026
Aerobic treatment unit system, residential scale (Georgia)
$10,000–$20,000
per system
Typical market range — Septic & Well Pro — Septic Installation Cost Georgia 2026 (updated June 9, 2026), 2026
Level III soil classification (Georgia)
$500–$1,500
per report
Typical market range — Septic & Well Pro — Septic Installation Cost Georgia 2026 (updated June 9, 2026), 2026
Drain field installation (Atlanta)
$5,000–$12,000
per field
Typical market range — Angi — Cost to Install a Septic System in Atlanta (2026 data), 2026
Pumping a large commercial tank
$300–$600
per visit
Tanks over 10,000 gallons cost more.
Typical market range — NTO Tank — Commercial Septic Tank Pricing: Business Owner Guide to Costs (March 11, 2025), 2025
Commercial annual inspection
$300–$500
per year
Typical market range — NTO Tank — Commercial Septic Tank Pricing: Business Owner Guide to Costs (March 11, 2025), 2025
These are published third-party typical market ranges (Septic & Well Pro 2026, Angi 2026, NTO Tank 2025), not our prices. Commercial systems are priced from the approved design; the on-site estimate is free.
Free estimate: (678) 863-5620Homes & businesses
Residential
Sized by bedrooms: a 1,000-gallon tank covers one to four, with 250 gallons more for each additional bedroom, and the field comes from the bedroom-based table. The residential permit fee applies.
Commercial
Sized by use from Table 13.J, with a trench-length formula tied to the soil, pretreatment where waste is strong, dosing on long fields, commercial permit fees, and engineering and commercial installer certification at 2,000 gpd.
FAQ
Straight answers, with the rule or record behind them. Still unsure? Call and ask the crew that digs.
(678) 863-5620Multiply the facility's unit count by its gallons per day in Table 13.J of the DPH Manual, add every use in the building together, and design for that peak flow. The soil's percolation coefficient then turns gallons into trench length. The county permit sets the final figure.
When its design flow is in excess of 2,000 gallons per day. Rule 511-3-1-.03(6) then requires the plans, specifications, soil data and absorption test data to carry a Georgia-registered engineer's seal. Smaller systems can be designed by someone the county considers qualified.
Source: Georgia DPH Rules Chapter 511-3-1, On-Site Sewage Management Systems (Jan 2016)
Yes. The DPH Manual's certification section says a commercial certification is required for contractors installing a system designed for 2,000 gallons per day or more. You can check any contractor against the DPH installer list before you sign.
Source: Georgia DPH Manual for On-Site Sewage Management Systems (March 2026) — Section N Certification
It depends on flow, soil and setbacks. The Manual's recommended lot-sizing criteria cap flow at 600 gallons per acre per day on a private well and 1,200 on public water, and require an equal replacement area. Walton County enforces those caps by ordinance.
GNR Public Health charges $600 for a commercial site evaluation, permit and initial inspection in Newton, Rockdale and Gwinnett. Walton charges $550 or $850 for new commercial inspections depending on flow, and DeKalb $400 or $600. Soil reports and engineering are separate.
Source: GNR Environmental Health Fee Schedule — Newton County (effective Jan 1, 2026)
It can, with pretreatment. Food service is footnoted in Table 13.J because its waste often exceeds 200 mg/L BOD5 and TSS, and Rule .03(1)(c) requires that to be reduced before a conventional or chamber system. Restaurants open under 24 hours are sized at 50 gallons per seat.
Length, not only elevation. The Manual requires a dosing tank on a conventional system that needs more than 500 linear feet of trench, so the whole field gets an even dose. Many commercial fields pass that length even on a favorable slope.
Plan for weeks, not days. The soil report, design, any engineering and the county's permit review all come before digging, and the county must inspect before backfill. The permit itself is good for up to 12 months, which gives room to schedule the dig around the building's opening.
Source: Georgia DPH Rules Chapter 511-3-1, On-Site Sewage Management Systems (Jan 2016)
Keep going
Sources
Rules, costs and local facts on this page link to the agency, code or publisher that states them. Cost figures are third-party market ranges, not our prices — estimates are free.
Reviewed by Atlanta Water & Sewage Solutions · Last updated
Ready when you are
A business lot past the end of the sewer main needs a system sized for its busiest hour, not a family's weekday. We start from Georgia's sewage flow schedule, work through the soil report, permit and inspection with the county, and install the tanks, pumps and field that the approved design calls for.
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