Backflow Preventer Approval & Cross-Connection Testing: Boston restaurant guide

Boston Water and Sewer Commission

What it is

Commercial kitchens need backflow prevention so equipment like dish machines, soda systems and boilers can't contaminate city water. BWSC reviews the device design and inspects devices on a schedule.

When a restaurant needs it

Restaurants installing water-connected equipment that creates a cross-connection.

How to apply

The plumber/engineer submits BWSC's Backflow Preventer Device Design Data Sheet, installs the approved device, and has it tested.

Documents you’ll need

Backflow Preventer Device Design Data Sheet
Device make/model
Test reports by a certified tester

Fee

Varies — contact BWSC

Processing time

Varies

Renewal

Cross-connection inspections: annual for double-check valve assemblies, semi-annual for other backflow devices

Who files

Designed and installed by a licensed plumber; tested by a certified backflow tester.

Good to know

ISD Health's pre-operational checklist also looks for backflow devices, so install them before that inspection.

Official source

BWSC — applications, inspections & permits

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Last reviewed 2026-10-06. Guidance only, not legal advice.