Seattle Public Utilities is about to start a round of testing in the Arbor Heights area that might look startling. Here’s the notice sent to us to share with the wider community:

SEWER INSPECTIONS WITH NON-TOXIC SMOKE

PROJECT DESCRIPTION
Seattle Public Utilities is using a testing method called “smoke testing” to find sewer leaks and/or pipe connection problems. A contractor, Pro-Vac, will be in your neighborhood blowing a colorless water vapor or “smoke” into sewer pipes via maintenance holes; the “smoke” is non-toxic and non-staining but may have a distinctive odor. “Smoke” or its odor is not anticipated to come into your house or building if your plumbing is in good working order and your “p-traps” (the U-shaped pipes under each drain) are filled with water.

SCHEDULE
This work is scheduled for late July through end of August. You will receive a door hanger notice 24- to 48-hours before the inspection. Prior to the testing, consider running water for 30 seconds in all your sinks, baths, and showers and pouring water in exposed floor drains.

LOCATION
The testing uses maintenance holes within the public right-of-way throughout the Arbor Heights Neighborhood. The “smoke” may travel up to 1,500 feet within the sewer pipe.

IMPACTS
Homes and businesses will continue to receive normal sewer services during the inspection.
 You may see or smell the “smoke” coming from maintenance holes in the street or right-of-way, sewer vents from roofs or coming out of the ground. This is normal and you do not need to do anything. You may talk with the on-site workers conducting the inspections if you have questions.
 If you see or smell “smoke” in your house or building, open doors or windows to increase ventilation. The
vapor should clear within a few minutes.
 If smoke continues to remain in your building for more than 5 minutes, talk with the field representatives or
on-site workers conducting the inspections. You may also contact SPU’s emergency Operations Response
Center (ORC) at (206) 386-1800.

“Smoke” may have entered your building due to issues with your building’s sewer pipe vents and/or p-traps under sinks, tubs or other drains. If “smoke” came into your building that did not stop when you put water in a drain, please consider contacting a plumber to investigate possible issues with your plumbing.

Here’s the notice in PDF.