Smoke Testing 2021 Letter to Residents

January 4, 2021

The City of White Plains is in the process of conducting a Sanitary Sewer Evaluation Study (SSES,) as required by Westchester County, in order to reduce Inflow/Infiltration (I/I) into the sanitary sewer. The purpose of this study is to determine and eliminate locations where excess rainwater and/or illicit connections (inflow) and groundwater (infiltration) may be entering sanitary sewer pipes and manholes.

This letter is to notify you that the Department of Public Works (DPW) intends to start “smoke testing” the sanitary sewer lines in specific neighborhoods as part of our SSES. Testing will occur between the hours of 8:00 a.m. and 4:30 p.m., and will be performed by Subsurface Utility Imaging (SUI). The smoke testing will begin on Wednesday, January 6, 2021, in various neighborhoods, and is expected to be completed within approximately two (2) months. Please refer to the attached project schedule for smoke testing locations and their approximate dates.

During the work, DPW personnel and Dolph Rotfeld Engineering, P.E. will be present to document findings and address any questions or concerns by the public. All City, Consultant and SUI staff will be properly identifiable. The Department of Public Safety will also be notified of the testing locations and schedule.

The smoke used for this testing is non-toxic and non-hazardous when used as directed. It is manufactured specifically for these testing purposes. This type of testing is a standard method of detecting sewer defects (i.e. breaks, leaks, etc.) and in identifying illegal cross connections (i.e. storm water sump pumps, etc.) to the sanitary sewer system. Smoke testing consists of placing a high capacity blower/pump on top of a sanitary sewer manhole and forcing the “smoke” down into the sanitary sewer system. The smoke is pressurized from the blower and travels through the sewer system. The smoke will escape only through connections, cracks, leaks, etc., in the sewer and will reveal any sources of inflow/infiltration within the study area.

Since the plumbing fixtures in your home or building are connected to the sanitary sewer system, smoke may enter your home of place of business only if any of the following conditions exist:

1) Vents connected to your building’s sewer pipes are inadequate, defective or improperly installed;

2) Traps under sinks, tubs, basins, shower and other drains are dry, defective, improperly installed or are missing;

3) Pipes, connections and seals of the wastewater drain system in and under your buildings are damaged, defective, are improperly installed or have missing sewer trap/cleanout caps.

Smoke should not enter your home. However, if it does, this may be an indication of a defect in your sanitary plumbing system. This defect could allow sanitary sewer gasses from the City’s sewer main to enter inside your home, which is a potential health hazard. Corrections of such defects on private property are the responsibility of the property owner to remediate. A licensed plumber should be consulted to ensure the proper corrections are made. If smoke does enter your home or building, ventilate the room and immediately bring it to the attention of Public Works; Dolph Rotfeld Engineering, P.E. and or SUI personnel in the area.

If you have any questions or concerns, or if your encounter smoke within or adjacent to your building, please contact DPW at (914) 422-1215 (between 9:00 a.m. – 5:00 p.m.) or after hours call (914) 422-1333 on the Water Bureau’s 24 Hour Emergency Hotline.

We appreciate your cooperation and understanding while we complete this necessary testing.


       Richard G. Hope, Commissioner of Public Works