Stormwater Technical Information
  • Technical &
  • Operation &
  • Business
  • Floodplain
  • Stormwater
  • Regulations

Stormwater Management

Address: 347 Phillips Drive, McDonough, GA 30253
Tel: (770) 288-7246 / Tel: (770) 288-RAIN / Fax: (770) 288-7257
Hours: Mon - Fri: 7:30a - 4:30p


MISSION: To effectively and efficiently manage stormwater runoff and protect the safety, property and environmental quality of unincorporated Henry County.

***Henry County Stormwater Management (HCSM) is a separate entity from the Henry County Water Authority (HCWA). Click here to learn differences in jurisdiction/operations between HCSM and HCWA.***


Technical & Engineering Documents

The documents in this section are designed to assist engineers with determining the many fundamental components needed to comply with the Georgia Stormwater Management Manual (GSMM) requirements, also referred to as the Blue Book.

Georgia Stormwater Management Manual: 
The ‘Blue Book’ provides technical guidance for the design, construction and implementation measures to improve stormwater management during the construction-phase of urban development. 
Download The Blue Book PDF

Henry County Operation & Maintenance Agreement
An Agreement between the Landowner and Henry County to construct and maintain stormwater management facilities. 
Download in PDF format

PE Certification for Compliance 
To be completed by the certifying engineer.
Download in PDF format

Plan Review Checklist

Removal Total for Suspended Solids 
Site review tool developed by CH2M HILL. Used as the standard for determining TSS removal efficiencies for BMP selection. Provides Total Suspended Solids removal (percent) based on the selected Stormwater Management design. Considers credits.
Download in Microsoft Excel format

Operation & Maintenance

Stormwater facilities include a wide assortment of structures designed to manage, treat, control and/or infiltrate the stormwater runoff from a certain area of land. Typical facilities include swales (channels), storm inlets, infiltration basins, and detention basins. A stormwater management facility, no matter how well-designed, cannot function without a suitable long-term maintenance program. Lack of proper operation and maintenance is often cited as the number one reason for failure of stormwater facilities.

Components of the Operation and Maintenance Plan

First is the creation of a detailed plan that establishes the Operation and Maintenance (O&M) program, including an O&M plan, for a specific site. The second step involves implementing the O&M program by performing site inspections and addressing maintenance issues as they occur. Implementation will require funding, record keeping, and the ability to enforce the O&M plan and agreement.

The O&M plan provides a general description of operation and maintenance activities for all stormwater facilities. Maintenance is divided into preventive, routine and *remedial categories. Source control is one example of a preventive maintenance strategy that seeks to protect the stormwater facility and therefore minimize maintenance by reducing runoff or pollutants at the source. Routine maintenance addresses the expected activities required to keep the stormwater facility in proper condition. Routine maintenance may include mowing, vegetation maintenance, and clean out of accumulated debris and sediment.

Privately owned (non-single-family residential developments), homeowners associations, merchants associations and private owners are responsible for maintaining the functionality of their stormwater management conveyance or device. Non-SFR properties are also tasked with retro-fitting their existing flood control device to include water quality to receive a stormwater utility fee credit.

Note: *Remedial maintenance refers to the non-routine or corrective maintenance, rehabilitation and/or reconstruction of the stormwater facility that is not otherwise addressed under routine maintenance. Remedial maintenance is typically done when some part of the facility deteriorates due to aging or damage. Remedial maintenance may involve repairing or replacing inlet or outlet structures, or repairing areas of excessive erosion and slope failure.

Business Information

Georgia National Pollutant Discharge Elimination System (NPDES)

On the Federal level, Stormwater pollution is regulated under the Environmental Protection Agency's (EPA) National Pollutant Discharge Elimination System (NPDES) permitting program. Georgia's NPDES permit program is administered through the Georgia Department of Natural Resources. In some cases, violators of NPDES permit requirements could receive heavy fines and stop work orders.

The Georgia Environmental Protection Division regulates Georgia’s NPDES General Permit No. GAR050000 (Permit) for Storm Water Discharges Associated with Industrial Activity authorizes point source discharges of storm water associated with industrial activity to waters of the State of Georgia. Permittees are required to implement appropriate storm water management practices to control pollutants in discharges of storm water associated with industrial activity from their facility.

Summary of Permit Requirements

  1. Obtain permit coverage
  2. Develop a stormwater pollution prevention plan. This includes SWP3 Contents (See part IV.D. of the permit) and implementation and maintain the SWP3
  3. Discharges to impaired stream segments. This includes determining if your facility is subject to part III.C. of the permit and numeric effluent limitations.
  4. Annual report . The annual sampling requires (Facilities identified in Parts VI.2.a ~ t.) annual sampling and analytical testing from the specific parameters listed in the permit, termination of coverage, and industrial no exposure exclusion

Please open the following link to review the detailed brochure of the Georgia Environmental Protection Agency NPDES Permit No. GAR000000 for Stormwater Discharges Associated with Industrial Activity: Informational Tri-fold Brochure for 2006 Industrial Storm Water Permittees [June 2006]

Types of Industrial Facilities Regulated by the Permit (General Permit #GAR050000)

The NPDES Storm water General Permit (General Permit #GAR050000) regulates storm water discharges associated with industrial activities which are designated under 40 CFR 122.26(b) (14) (i-ix) and (xi). The activities are divided into categories based on Standard Industrial Classification (SIC) code and narrative descriptions. A complete list of the categories and Standard Industrial Classification (SIC) can be found at Occupational Safety & Health Administration (OSHA).

Commercial Credit Information

Attention Business Community, as a reminder, please take a moment and review the credit summary.

In 2006, the Henry County Board of Commissioners adopted Ordinance 06-05 establishing a Stormwater Management Utility. The Ordinance includes provisions for a service fee exemption and credit policy. The policy is detailed in the Stormwater Utility Service Fee Credit Manual.

The policy provides an incentive for Non Single Family Residential land owners and managers to reduce the County’s stormwater management costs and thereby receive an appropriate adjustment in their fee. The application process and procedure is detailed on our department website. Additional assistance in applying for the fee reduction credits is available at the Stormwater Department or by calling 770-288-RAIN (7246).

Credit Schedule

The stormwater fee credit application process and schedule is as follows:

Period Time Action
January 1 to March 1 60 days Applications are received and recorded
March 1 to May 1 60 days Applications are reviewed and processed
May1 to July 1 60 days Period open for appeals (see section 4.5-Appeals of the Credit Manual )
July 1 to August 1 60 days Final Approved Credits are posted to the Master Account File

The application and fees may be delivered in person or by mail to:

Henry County Stormwater Management
Attention: SW Credit Applications
347 Phillips Drive
McDonough, Georgia 30253
770-288- RAIN (7246) 

State Environmental Links and Resources

For your convenience, we have provided additional industrial links and resources that can assist you in completing your NPDES Requirements. You may download and print the appropriate forms as needed.

  • Water Quality Act: Georgia environmental rules published on the Georgia Secretary of State web site and to corresponding laws published on the Georgia General Assembly web site.
  • The Watershed Protection Branch: This branch manages water resources in Georgia through permits to local governments and industry to discharge treated wastewater and to local governments. This Branch also conducts water quality monitoring and modeling of Georgia's waterways.
  • EPD Documents, Forms, and Applications: The Georgia Environmental Protection Division has made numerous forms available including permit applications, release notifications and reporting forms. The forms are organized by regulatory area within EPD.
  • NOI, NOT, and No Exposure Forms: Stormwater Forms and Documents.

Floodplain Management

Floods are one of the most common hazards in the United States, however, all floods are not alike. Flood effects can be local, impacting a neighborhood or community, or very large, affecting entire river basins. Some floods develop slowly, over a period of days. Some develop quickly, sometimes in just a few minutes and without any visible signs of rain. Flash floods often have a dangerous wall of roaring water that carries rocks, mud, and other debris and can sweep away most things in its path. Overland flooding occurs outside a defined river or stream.

It is important to be aware of flood hazards regardless of where you live. Even very small streams, gullies, creeks, culverts, dry streambeds, or low-lying ground that appears harmless in dry weather can flood.

This section provides citizens of Henry County with information and resources to familiarize themselves with the subject of flooding, and to become acquainted with the policies and programs related to flooding and floodplain management.

Helpful Links

  • Henry County Floodplain Mapping: Each panel is numbered. To locate a desired panel, zoom in and click that section for a more detailed view. Adjust your view settings to a desired area within a selected panel. To print, select File, Print and Current View. (Use Internet Explorer to open this link)
  • FEMA Flood Maps: Federal Emergency Management Agency
  • Georgia Flood Maps - Henry County: The Georgia Flood Map provides the latest in digital floodplain data. You can view and download the most recent flood insurance and basin information.
  • Floodsmart: Floodsmart provides detailed information about floods, risk of financial loss due to flooding and flood insurance. Sponsored by the National Flood Insurance Program.
  • Georgia Disaster History: A database of Region 4 (IV) FEMA emergency events.

Stormwater Credit

The key aspects of the credit policy were derived and affirmed through public meetings and guidance from the Board of Commissioners, Henry County staff, and a broad cross-section of stormwater program stakeholders. This public process identified certain essential objectives that are implicit in the stated policy. The objectives of the policy are to:

  • Promote equity among rate payers and within the rate structure,
  • Promote property owner participation,
  • Promote the implementation and maintenance of best management practices (BMPs),
  • Protect and preserve water quality, and
  • Prevent and reduce public expenditures on the stormwater management program.

Single Family Residence (SFR)

Single family residential (SFR) parcels are not eligible for the stormwater service fee credits specified in the Service Fee Credit Manual, as these parcels have already been provided with a built-in credit within the basic service fee rate structure. The stormwater fee rate structure incorporates a credit provision for SFR parcels in that all SFR parcels regardless of size are charged a single common annual fee. The single common fee recognizes that while larger parcels generally include more impervious area, the intensity of development of larger parcels, as indicated by the percent of imperviousness, is generally less and therefore serves to mitigate flooding and water quality impacts that may be attributable to a characteristically greater amount of impervious area.

This built in provision greatly simplifies and reduces the costs associated with implementation of the credit policy for SFR parcels. In essence, SFR parcels that may have been eligible for a credit are automatically granted one. Eliminating the potential case by case consideration of single family residential parcels supports the essential objective of preventing and reducing public expenditures on the stormwater management program. As of the 2008 property tax digest, there were 46,290 developed single family residential parcels in unincorporated Henry County.

NON-Single Family Residence (NSFR)

All Non-Single Family Residential (NSFR) parcels are eligible for consideration for service fee credits as specified in the Service Fee Credit Manual.

The Stormwater Utility Service Fee Credit Manual establishes criteria and a process for the appropriate and effective adjustment of stormwater fees to account for qualifying activities, practices, and property characteristics that reduce the County’s cost of services related to stormwater management. This policy is based on the following premises:

  • Property owners exercise control over factors that affect stormwater runoff quality and quantity.
  • Property owners may reduce the utility’s costs of services through development choices, specific property facilities, management practices, and services.
  • Stormwater fees and credits provide an incentive for improved watershed management practices.
  • The impervious area of a parcel is the primary basis for determination of the applicable base fee.

The Stormwater Utility Service Fee Credit Manual has been created to provide information and procedures for applying for a stormwater service fee credit or fee adjustment for factors related to the amount of impervious area.



Between 1972, when the first Clean Water Act was passed, and 1990, about $260 billion in private and public funds was spent on wastewater treatment facilities. Another $20 billion, most of it from the public sector, was spent to comply with federal requirements on drinking water quality. The 1987 amendments to the Water Quality Act were the first concerted effort by the federal government to address pollution from non-point sources, including agricultural fields and feedlots, urban streets, and runoff channeled through municipal storm-water systems. The law required states to develop a non-point-source management plan. The 1987 act also created and funded several special programs, including one to deal with toxic hot spots and one to protect estuaries of national importance.

There are various regulations in place at the local, state and federal level for the management of stormwater and water quality. To review additional environmental legislation please visit the respective websites.

Henry County Stormwater Ordinances

Henry County has enacted the following regulations for stormwater management and watershed protection. On September 15, 2009, the Board of commissioners adopted the Unified Land Development Code (ULDC). The ULDC replaces Chapters 3-6 through 3-11 of the Henry County Code of Ordinances.

To review the portions of the ULDC, please use the following steps:

  1. Access Municode
  2. Henry County, Georgia, County Codes
  3. Part III - County Ordinances
  4. Appendix A – Unified Land Development Code (ULDC)
  5. Locate the Chapter in the Right Section of the screen
  6. Access the relevant Section of the ULDC Code.

Unified Land Development Code




Code No.


Alternative Site Design Standards

Conservation Subdivision Development (CSD)
(Click here to view)



Protection of Natural Features and Resources

Floodplain Management / Flood Damage Prevention
(Click here to view)



Protection of Natural Features and Resources

Illicit Discharge
(Click here to view)



Standards for Stormwater Management

(Click here to view)



Protection of Natural Features and Resources

Stream Buffer Protection
(Click here to view)


County Code of Ordinances



Litter Control
(Electronic version pending)




Stormwater Management Utility
(Click here to view)



Awarding a Contract for Floodplain Mapping Services for the Stormwater Department
Georgia Stormwater Management Manual
Stormwater Stakeholder Advisory Committee
Inspection Staff to Locate Stormwater Outfalls
Metro North Georgia Water Planning District Model Ordinances: Litter Control, Illicit Discharge, Conservation Subdivision and Post Development Stormwater Management

For information on specific city ordinances and resolutions, please visit the following links.

City of Hampton
City of Locust Grove
City of McDonough
City of Stockbridge


Atlanta Regional Commission
Clean Water Campaign
Georgia Stormwater Management Manual (The Blue Book)
Metropolitan North Georgia Water Planning District

State Regulations

Pollution in our streams, lakes and rivers prevents these water bodies from meeting their water quality standards and designated uses regulated under the EPA's National Pollutant Discharge Elimination System (NPDES). For the State of Georgia the NPDES regulations are being administered by the Georgia Environmental Protection Division (EPD). Phase I of the NPDES (issued 1990) stormwater regulations were aimed at medium and large Municipal Separate Storm Sewer Systems (MS4s) with populations greater than 100,000 people. The Phase I regulations addressed discharges from regulated municipal, industrial, and certain construction activities.

Phase II of the NPDES Stormwater regulations (issued 1999) require that small MS4s (population less than 10,000) prepare and implement stormwater management plans to control pollution of stormwater from urbanized areas. Please visit the Watershed Protection Branch of the Georgia Environmental Protection Division (EPD) for a complete review of Georgia’s Environmental Rules and Laws.

State Rules & Laws

Environmental Protection Division (EPD)

Federal Regulations

The United States Congress enacted the Clean Water Act in the early 1970s to protect water resources throughout the nation. Since then, water quality in the United States has improved considerably. This legislation has provided the nation with a wide-ranging structure for principles; technical tools and financial assistance that can help improve water quality and reduce pollution.

Federal Regulations & Laws

Stormwater Final Rules
Clean Water Act
Environmental Protection Agency (EPA)
U.S. Army Corps of Engineers (USACE)