On Monday, December 3rd, OWASA will begin testing sewers at more than 400 locations in Chapel Hill and Carrboro by putting non-toxic smoke into sewer pipes. The testing may take several weeks to complete.

The testing will indicate locations where:

  • There are leaks or other openings in OWASA sewers and in private service pipes that drain to the sanitary sewer system. These locations will then be corrected to help keep stormwater and groundwater out of the OWASA sewer system, which is designed to collect wastewater. Where excessive stormwater or groundwater gets into a sanitary sewer, a wastewater overflow may occur.
  • Storm drains are connected (improperly) to OWASA’s sanitary sewer system.
  • There are unauthorized connections to an OWASA sewer.

Citizens may see smoke from OWASA’s testing come out of plumbing system vent pipes above the roof of a house or other building. This is expected and does not indicate a problem in the plumbing system

The smoke from OWASA’s testing should not get into the interior of a house or other building if there are no cracks, loose fittings/connections or other openings in the plumbing system.

However, smoke from the testing can get inside a building if there are cracks, openings, etc. in a plumbing system, or if the “P-trap” under a sink, in a floor drain or in a toilet is dry.

Customers who believe a p-trap is dry due to lack of use, etc. should run water in the sink, flush the toilet or pour water in the drain to fill the P-trap. A P-trap looks like this:


For more information

Thurman Green, Manager of the Collection and Distribution Systems, 919-537-4224 or