DEP backflow prevention device: New York City restaurant guide
NYC DEP
What it is
An approved backflow prevention assembly (RPZ or double check valve) protecting the city water supply, with an annual test by a certified tester.
When a restaurant needs it
Required for premises with commercial kitchens — DEP's list of premises that must install a backflow device includes 'Premises with Commercial or Public Kitchens' and 'Food Preparation Facilities'.
How to apply
A PE or RA mails two copies of the application and drawings to DEP Cross Connection Control; after approval, a Licensed Master Plumber installs under a DOB permit and initial test results go to DEP within 30 days.
Documents you’ll need
- Backflow plans (P.E./R.A.)
- Device specs
- Initial test report
Good to know
DEP's list of premises that must install a backflow device includes commercial kitchens and food preparation facilities, so plan on one for any restaurant kitchen. It's frequently overlooked until the end — design it in early.
Official source
DEP — backflow prevention · NYC Business — application
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Last reviewed 2026-10-06. Guidance only, not legal advice.