Concrete Sewer Lines in D.C. We had a property management client with aging concrete sewer lines carrying waste off the property under a natural flowing creek to the WSSC – Washington Sanitary Sewer Commissions collection system. The concrete sewer lines were 40 plus years old and were backing up a couple times a year. Risking the natural environment was not an option. The Perma-Lateral air inversion system was brought in to fix the aging concrete sewer lines. We had two days to complete more than 300 feet of aging 6” concrete sewer lines. The commercial property was fixed and guaranteed for another 50 years. If you live in the Washington D.C. area or the Northeast United States, please call us at anytime.