Stormwater Fee Reduction Studies: How to Lower Your Atlanta-Area Property’s Stormwater Bill
Most commercial property owners in the Atlanta region pay a monthly or annual stormwater utility fee on top of their other property taxes and utilities. The fees are calculated based on the amount of impervious surface — rooftops, parking lots, driveways — and for large commercial sites can run into the tens of thousands of dollars per year. What most owners do not know: the same jurisdictions that bill the fee almost always offer credits, sometimes up to 100%, for properties that manage their own stormwater on site.
A stormwater fee reduction study is the engineered application that documents your eligibility and unlocks those credits. For the right property, the study pays for itself many times over in the first year.
Key Takeaways
- Most Atlanta-area jurisdictions — DeKalb, Gwinnett, Atlanta, and others — assess stormwater utility fees based on impervious surface area.
- DeKalb County offers fee credits of up to 40% for properties meeting Water Quality, Channel Protection, Overbank Flood Protection, and Extreme Flood Protection criteria (10% per category).
- DeKalb offers a 100% credit for properties with no stormwater discharge to the county system.
- Gwinnett County offers credits up to 40% across BMP and watershed stewardship categories.
- Most jurisdictions accept credit applications only during a specific annual window (in DeKalb, January 1 to March 31) and applicants are notified within 45 days.
- Applications require a stamped engineering study including site plan, impervious area mapping, BMP documentation, and an Operation and Maintenance Plan.
- Credit must be reapplied for annually in most jurisdictions to remain active.
Why Stormwater Utility Fees Exist
Atlanta-area jurisdictions established stormwater utilities to fund maintenance of public drainage systems, regulatory compliance with their MS4 permits, and capital improvements like pipe replacement. The fee is calculated based on impervious surface area because impervious surface is the primary driver of stormwater runoff volume and pollution loading. DeKalb County’s utility went into effect January 1, 2004; Gwinnett’s ordinance dates to November 2005; the City of Atlanta is actively evaluating one; the City of Savannah approved one in January 2026.
How DeKalb County Credits Work
The DeKalb County Stormwater Utility Fee Credit Manual offers credits in 10% increments tied to the Unified Stormwater Sizing Criteria of the Georgia Stormwater Management Manual:
| Credit Category | Credit | Requirement |
| Water Quality | 10% | On-site BMPs sized to meet WQv per the GSMM |
| Channel Protection | 10% | On-site BMPs sized to meet CPv per the GSMM |
| Overbank Flood Protection | 10% | On-site facilities meeting Qp25 criteria |
| Extreme Flood Protection | 10% | On-site facilities meeting Qf criteria |
| Maximum Total Credit | 40% | — |
| No-Discharge Credit | 100% | No stormwater discharge to the county system at all (100-year storm) |
How Gwinnett County Credits Work
Gwinnett offers credits in four categories — Watershed Stewardship, Water Quality, Channel Protection, and Peak Flow — also totaling up to 40%. Gwinnett’s system is calculated through specific BMP mitigation formulas (e.g., square feet of mitigation versus square feet of impervious area). Watershed Stewardship credits include education and outreach activities — a 5% credit is available for hosting a qualified stormwater education event.
Who Should Pursue a Fee Reduction Study?
The economics work best when:
- Your annual stormwater bill is large enough that 20–40% off justifies the engineering fee (typically $25,000+ annual fee)
- Your property already has detention, water quality, or other BMPs from original site design
- Your property is a large commercial, industrial, multi-family, or institutional site
- Your property is in DeKalb, Gwinnett, or another Atlanta-area jurisdiction with an active credit program
- You have site plans, as-builts, and BMP documentation available
What a Stormwater Fee Reduction Study Includes
At a minimum, a credit application package must include:
- A site plan showing all impervious areas, drainage patterns, contributory drainage areas, and the location of stormwater management facilities
- A description of the stormwater facilities
- A technical report documenting that the facilities meet one or more credit criteria
- An Operation and Maintenance Plan designating who is responsible for the long-term maintenance and performance of the facilities
- A signed credit application form
The Application Process
- Confirm your jurisdiction offers a credit program and obtain its current credit manual.
- Gather existing site plans, as-builts, and BMP documentation.
- Hire a Georgia-licensed civil engineer to evaluate eligibility, model BMPs, and prepare the technical report.
- Develop or update the Operation and Maintenance Plan.
- Submit the application within the jurisdiction’s annual window (in DeKalb, January 1–March 31).
- Respond to any reviewer requests for additional information.
- Receive credit determination — DeKalb notifies applicants within 45 days.
- Reapply annually to maintain the credit.
What Owners Get Wrong
- Assuming the credit applies retroactively — it usually does not
- Missing the annual application window and waiting a full year
- Submitting an application without a Georgia-licensed PE seal
- Ignoring the Operation and Maintenance Plan, which jurisdictions take seriously
- Letting maintenance lapse, which can result in the jurisdiction revoking the credit
Frequently Asked Questions
How much can I actually save?
On a 10-acre commercial site with a $35,000 annual stormwater fee, a 30% credit translates to $10,500 per year. Over a 10-year hold, that is over $100,000 — typically 10x or more the cost of the engineering study.
Do I have to install new BMPs to qualify?
Not necessarily. Many older commercial sites already have detention ponds, water quality structures, or other facilities that qualify with documentation. The engineering study evaluates what you already have.
Does the credit transfer when I sell the property?
Most jurisdictions require the new owner to reapply, but the BMPs and documentation transfer with the property — meaning the new owner can typically reinstate the credit quickly.
What if I have no detention on my site?
You may still qualify for a partial credit through Watershed Stewardship activities (in Gwinnett) or through stormwater education programs. The economics rarely justify the study without at least one structural BMP, however.
Do residential property owners qualify?
Some jurisdictions offer residential credits for rain barrels, rain gardens, or pervious surfaces, but the dollar savings are small. Most fee reduction studies are pursued by commercial, industrial, multi-family, and institutional property owners.
Ready to move your project forward?
Mack Engineering is a full-service civil engineering and land development firm based in Alpharetta, Georgia. We deliver fast turnarounds, single-PE accountability on every project, and deep working knowledge of the permitting offices across Metro Atlanta — Cherokee, Forsyth, Fulton, Cobb, and surrounding counties. Whether you are a developer, builder, property owner, or buyer, we will tell you the truth about your site before you spend money you cannot get back. Contact Mack Engineering for a no-obligation consultation or to request a fixed-fee quote.