The City of Roswell will reopen City Hall (38 Hill Street) and their facility at 1810 Hembree Road on Monday, June 15, 2020. Both facilities will resume normal business hours and will be open for walk-in appointments, Monday-Friday, 8:00 a.m. to 5:00 p.m. Please visit for details and for information regarding the City of Roswell coronavirus response.

Backflow Prevention

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Chris Boyd
Chris Boyd
Water Utility Manager
Email Chris Boyd

Jason Downs
Water Distribution Supervisor
Email Jason Downs

Phone: 770-641-3707
Hours & Location
Monday - Friday
7:00 AM - 4:00 PM

105 Dobbs Drive
Roswell, GA 30075


The City of Roswell has developed a Backflow Prevention Program to comply with Federal and State laws regarding safe drinking water. The purpose of this program is to prevent the introduction of contaminants or pollutants into the potable water system. The program applies to all commercial and residential customers of the City of Roswell's Water Utility.

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What is Backflow
Backflow is the undesirable reversal of flow of a liquid, gas, or other substance in a potable water distribution piping system as a result of a cross connection. Backflow contamination of a public water system by contaminants and pollutants through uncontrolled cross connections could occur as a result of the reversal of flows brought about by fluctuations in water pressure within the water system (i.e. main break, fire fighting, etc.).

The requirements for the level of protection are based on the following criteria:

  • High Hazard: A facility considered as a possible source of contaminates. Contaminates are toxic substances or those creating a health hazard due to the nature of the product. This category would include multi family dwellings, hospitals, doctors, dentists offices, metal plating operations, chemical companies, facilities that have the capabilities of exerting back pressure on their water tap and other industrial businesses using toxic substances. These operations would be required to install a reduced pressure principle backflow prevention assembly (RPZ) for maximum protection.

  • Medium Hazard: A facility considered as a possible source of pollutants. Pollutants are substances considered to be objectionable in nature such as those causing discoloration, odor, or taste in water. This category would include commercial businesses such as grocery stores, restaurants, day care centers, office buildings, and any business that has an auxiliary water supply. Automatic sprinkler systems would also apply to this category. These operations would require and double check backflow prevention assembly (DCV) for their required degree of protection.

  • Low Hazard: Considered to be the least likely to be a source of contaminant or pollutant. Typically this would include only a single or duplex family dwelling served by a single water meter. The City of Roswell’s Water Utility has installed dual check valves at the meter.

For questions the City of Roswell's Backflow Prevention Program, please contact Chris Boyd at 770-641-3707.

What is Thermal Expansion
When water is heated and stored in a distribution system or a branch of the system that has been closed by the installation of a backflow prevention device or any other checking device, an approved auxiliary relief valve, or expansion chamber should be installed to limit thermal expansion of the water being heated to not more than 80 PSI no-flow pressure at any fixture on the system. The installation of such a device shall be in accordance with State Plumbing Code (Section 1112.8) and shall be the responsibility of the customer.

It is the customer's responsibility to determine whether thermal expansion is a possibility. City of Roswell is not responsible for damages occurring within the customer's water system.

More information regarding Thermal Expansion

Backflow Specifications
Backflow specification and details for backflow prevention devices for various sizes:


  • Are there any regulations in OSHA regarding cross connections?
  • Where is a reduced pressure zone backflow preventer (RPZ) used?
  • Where is a double check backflow prevention assembly used?
  • What are the 5 basic products used for backflow protection of cross connections?
  • What is the difference between a toxic and non-toxic substance?
  • What is meant by degree of hazard?
  • What is the difference between pollution and contamination?
  • What protection is required for sill cocks?
  • What is potentially dangerous about an unprotected sill cock?
  • What is potentially dangerous about an unprotected sill cock?
  • What is the most common form of a cross connection?
  • What is a cross connection?
  • What factors can cause a back pressure backflow condition?
  • What is back pressure?
  • What factors can cause back-siphonage?
  • What is back-siphonage?
  • What is Backflow?
More FAQs >