Prevent Sewage Backflow


Legislation at a Glance

8: Prevent Sewage Backflow


Local Law 83 of 2013


During floods, sewage can backflow into buildings if the sewer system is overwhelmed with floodwaters. Valves on building sewage lines can prevent sewage from entering the building.

New Requirements or Changes

Effective: December 31, 2013

Amendments to Sections 715.1.1 and 1001.9.1 of NYC Plumbing Code, Section G501.1 of NYC Building Code, and Sections 7.3.3 and 7.3.4 of ASCE 24-05.

This legislation requires that, in buildings located in Special Flood Hazard Areas as defined by the Building Code, the building drains must be equipped with a backwater valve at the point of exit from the building and downstream from the building trap.


These requirements are part of the plumbing code, and will be enforced by the Department of Buildings.


There are no known issues with implementing this legislation.