Sewer Conveyance

The PWSA Sewer System

The PWSA sewer system is composed of 1,200 miles of sewers and more than 25,000 catch basins. The sewer collection system is primarily a combined collection system that serves the entire City of Pittsburgh.  

The PWSA sewage collection system also serves as a conveyance system for portions of flows from 24 neighboring municipal communities.  

Wastewater flows generated from neighboring communities are conveyed through parts of the PWSA collection system to the Allegheny County Sanitary Authority (ALCOSAN) interceptor system.  The wastewater collected by the PWSA system is conveyed to ALCOSAN for treatment. 

Sewage Treatment

PWSA conveys sewage to the Allegheny County Sanitary Authority (ALCOSAN) for treatment. For more information, visit

What to do if your sewer backs up and contaminates your home? 

Once a back-up is indicated, contact The Pittsburgh Water and Sewer Authority immediately. While you are waiting for one of our crews to come out and assess the situation, please also contact your neighbors to see if they are experiencing any problems.

If there is a problem with the main sewer line, PWSA is responsible to fix it. However, if there is a problem with the sewer lateral, the homeowner is responsible to fix it.

Once the problem is corrected and the sewage has dissipated in your home, you may begin the clean-up process.

Steps to Clean Up the Contaminated Area

  1. Clean and disinfect washable surfaces that have come in contact with sewage.
  2. Wash with soap and water, then disinfect with a mixture of a quarter cup of household bleach per gallon of water.
  3. Discard upholstered furniture, mattresses, bedding and stuffed toys soaked in flood waters.
  4. Sweep or vacuum soaked and soiled carpeting, then shampoo it with a commercial rug cleaner.
  5. Clean, dry and check your furnace, water heater, washer, dryer and other appliances before using them.
    • Don't handle electrical equipment in wet areas. Call a plumber or an electrician for professional service.
  6. To remove odors from refrigerators and freezers, use warm water with a detergent and wipe dry.
    • If an odor persists, try a solution of one teaspoon of baking soda or one cup of household ammonia per gallon of water.
  7. Throw away all foods that have come in contact with flood waters.
  8. Make sure everyone involved in the flood cleanup has an up-to-date tetanus shot.
    • Boosters are recommended every ten years. 

Property Damage from Sewer Backups

If you have ever experienced property damage caused by a sewer backup, chances are you found that damage was not covered by your insurance.

All local governments in the Commonwealth of Pennsylvania are afforded sovereign immunity against third party claims for property loss damage under the Political Subdivision Torts Claim Act. Some exceptions do apply, but generally conditions are very specific for exceptions to be validated.

The Tort Claims Act states that “a local agency cannot be held liable for a dangerous condition of water or sewer system unless it had actual notice or could reasonably be charged with notice under the circumstances at sufficient time prior to the event to have taken measure to protect against the dangerous condition.”

Most sewer system backups are unforeseen events, and generally don’t fall under the exception. Therefore, damages to your property are not covered by The Pittsburgh Water and Sewer Authority (PWSA). PWSA encourages you to review your current insurance policy with your insurance agent.