Sewer Capacity Certification is a process where every new development which will require connection of its sanitary sewer service to the City of Atlanta’s sewer system is reviewed to determine whether or not there is adequate capacity in the sewer system to convey the new sewage flow from the proposed development to the water reclamation center (WRC).

Who Should Apply?

Everyone proposing a new development within the city limits of Atlanta whose development will be served by the City of Atlanta’s sanitary sewer system should apply. There are certain developments that do not require capacity certification. Sewer capacity certification analysts from the City of Atlanta’s Department of Watershed Management will determine whether or not your proposed development needs sewer capacity certification when you apply.

Does It Cost Money To Apply?

A Capacity Certification Fee is required per the City of Atlanta Ordinance 04-O-1873

The flat rate for single family residential and commercial flows less than 2,500 gallons per day (gpd) is $600.
The flat rate for commercial permits for flows of 2,500 gpd or greater is $1,500. Additional fees for permits in capacity limited basins, requiring Capacity Certification analyses may apply as follows:
Flat rate for simple analysis of possible capacity options (upon request of applicant) is $2,245.
Additional actual charges for modeling, site visits, and Alternative analysis (actual fee will vary depending upon services reuired or reqested)

Where Can I Get More Information?

For more information on sewer capacity certification contact Mr. Dennis Morris,
Department of Watershed Management at (404) 330-6249.
How Do I Determine Sewage Flowrate From My Proposed Development?

The City of Atlanta’s Standard Sewage Flowrates – Table 1 is attached for determining the sewage flowrate from your proposed development.

If the total sewage flowrate from your proposed development is less than 2,500 gallons per day (GPD), your sewer capacity certification application will be accepted and processed.

If the total sewage flowrate from your proposed development is 2,500 GPD or higher, a hydraulic analysis report by a state of Georgia licensed Professional Engineer will be required prior to processing of the sewer capacity certification application.
Please refer to the Hydraulic Analysis Process section of this guideline.
Hydraulic Analysis Process

1. Proposed Developments In Separate Sanitary Sewer Basins

I. Estimate New Sewage Flowrate and Design New Sewer Line

Determine the total sewage flowrate from the proposed development using the City of Atlanta’s Standard Sewage Flowrate, Table 1 attached.
Multiply the total sewage flowrate in item (a) by a peaking factor of 4.0 per City of Atlanta Code of Ordinance.
Use the peak sewage flowrate in item (b) to design the sanitary sewer from the proposed development to an existing City of Atlanta sanitary sewer manhole.

II. Evaluate Impact On Existing Sewer Laterals

From the existing manhole for the proposed connection to the nearest major sewer trunk, obtain existing pipe size, pipe material, flow depth and slope of the out going pipe. (See Appendix A)
Convert the measured flow depth to flowrate in gallons per day (GPD).
Add the peak sewage flowrate in I. (c) to the flowrate in II. (b). The result is the total flowrate that the existing sewer must have the capacity to convey from point of connection to the nearest major sewer trunk without surcharging.
If the existing sewer does not have adequate capacity to convey this flowrate, the existing sewer must be replaced by the developer with a new sewer with adequate capacity. The new sewer will be designed with a peaking factor of 4.0 and a 50-year build-out of the service area.

2. Proposed Developments In Combined Sewer Basins

I. Estimate New Sewage Flowrate and Design New Sewer Line

(a) Determine the total sewage flowrate from the proposed development using the City of Atlanta’s Standard Sewage Flowrate, Table 1 attached.
Multiply the total sewage flowrate in item (a) by a peaking factor of 4.0.
Use the peak sewage flowrate in item (b) to design the sanitary sewer from the proposed development to an existing City of Atlanta sanitary sewer manhole.
Perform a hydrology study of the project site being developed . The results of the hydrology study and the peak sewage flowrate found in item (b) are to be used to develop a stormwater management facility. The stormwater management facility shall limit the peak flowrate from stormwater runoff on the new development from a 1-year recurrent storm to a value no greater than the value of 70% of the pre-development peak flowrate from stormwater runoff from a 1-year recurrent storm minus the peak sewage flowrate (see equation below). Other requirements of the City of Atlanta’s Stormwater Management Design Manual must also be met.

Equation: Qspa = (Qspb * 0.7) – Qwpa
where
Qspa is the Peak Stormwater flowrate after development,
Qspb is the Peak Stormwater flowrate before development, and
Qwpa is the peak sewage flowrate from the development.