New York State law requires certain businesses and residential properties to install and maintain backflow prevention devices.

Backflow prevention devices stop contaminated water or chemicals from flowing back into the drinking water supply if there is a sudden or unexpected change in water pressure.

The Department of Environmental Protection (DEP) answers questions about these devices and general questions about the program.

Online

Learn more about cross connection control and water backflow prevention.

By Phone

Call 311 or 212-NEW-YORK (212-639-9675) for help.

Unless they receive a specific exemption, the following types of businesses are required to use backflow prevention devices:

  • Auto repair shops
  • Breweries
  • Canneries
  • Commercial car washes
  • Dye plants
  • Exterminators
  • Food processing plants and meat packers
  • Funeral parlors
  • Greenhouses
  • Hospitals, clinics and laboratories (including veterinary hospitals)
  • Large residential dwellings with water boilers that use rust-inhibitors or other treatment chemicals ("treated water boilers")
  • Laundries and dry cleaners
  • Medical and dental offices
  • Metal platers
  • Photo-processing facilities
  • Paper processors
  • Premises with multiple water service lines
  • Premises with roof tanks and elevated storage lines
  • Sewage treatment plants or handling facilities
  • Shipyards and marinas
  • Tanneries

You need a to hire a Professional Engineer (PE) or Registered Architect (RA) to install a backflow prevention device. The PE or RA must follow the procedures in the Department of Environmental Protection's Cross-Connection Brochure. The brochure, supporting documentation, and forms are available online.

Learn more about cross connection control and water backflow prevention.

Exemptions must be filed by a Professional Engineer (PE), Registered Architect (RA), or Licensed Master Plumber (LMP) on behalf of the property owner. 

The PE, RA, or LMP must provide all required information in a typed letter on letterhead. The letter must state that all necessary exemption conditions have been met. It must be sent to the Department of Environmental Protection (DEP) for approval. An exemption guide is available online.

Learn more about cross connection control and water backflow prevention.

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