Protect Our Sewers
What should and should not go down the drain (to our sanitary sewer system)?
Our sanitary sewer system and wastewater treatment plant are designed to collect and treat dirty water that has been used for toilet flushing, bathing and showering, washing clothes and dishes, cooking and food preparation, routine cleaning and other normal residential, business and institutional purposes.
Our sewer system should not be used to dispose of liquids and substances which:
- are poisonous, explosive or flammable.
- could clog a sewer pipe and cause wastewater to overflow from a sewer manhole or clog a plumbing drain and cause a back-up inside a home or business. (Examples: Fat, oil and grease, trash and debris). For more information on proper disposal of fat, oil and grease to help prevent wastewater overflows, please click here.
- could harm the bacteria and other microorganisms that remove pollutants from wastewater in biological processes at our treatment plant. (Examples: fuel, various solvents, petroleum products)
- should go into the separate “stormwater” system of catch basins, pipes, ditches, creeks and streams, etc. (Stormwater is rainwater that has fallen on buildings, paved areas, lawns and other landscaped areas, etc. OWASA does not provide stormwater services; please check with your local government for information on stormwater policies/services.)
- should be disposed of in the hazardous waste program in our region. (Examples: paint, oil, etc.)
Wastewater treatment plants are not designed to remove pharmaceutical compounds. Therefore, prescription medication should not be flushed down the toilet.
The Chapel Hill and Carrboro Police Departments have "drop box" programs for safe disposal of unused medication. Please click here for more information including the locations, days and hours when drop boxes are available for medication disposal, and the kinds of items that are eligible for this program.
For more information, please see What Should and Should Not Go into the OWASA Sewer System and our Sewer Use Ordinance.
Roots, sewage overflows and clearing of our easements. The roots of trees and shrubs are naturally attracted to our sewers because of the nutrients in wastewater. When roots grow into a sewer through even a small opening at a pipe joint or crack, the roots will form a dense matte that will block the flow of sewage and cause it to overflow from a manhole. We therefore mow and otherwise clear our sewer easements about once a year to help prevent roots from growing into and blocking our sewers; and to maintain safe, quick access for maintenance, repairs, inspections and emergency response if there is a wastewater overflow. For an electronic brochure explaining what sewer easements are and why we clear them, please click here.
If you have shrubs, plants or structures in an OWASA easement, we may need to ask you to remove or relocate them to help prevent wastewater overflows and/or maintain access. Also, if you wish to do plantings in an OWASA easement, please click here for information about plants that may be suitable, where they may be planted and requesting approval of a landscape plan.
Reporting wastewater overflows, and debris and trash disposal in sewers, and tampering. If you see or suspect an overflow from our sewer system, please call us immediately at 919-968-4421. We have personnel on duty and on call 24 hours a day to receive calls and respond to water/sewer emergencies involving the OWASA system. (We do not repair private plumbing systems).