If an overflow occurs, call our Sewer Collection Division at (301) 739-8577 extension 661 or 651 during normal business hours or (301) 790-3205 for after hours, weekends, and holidays.When you call us first, you could save the unnecessary expense of a plumber. Discontinue inside water use. If your sewer cleanout near the street is accessible, our personnel will be able to determine if the blockage is in the customer’s line or in the city’s line. If the blockage is in the city’s line, our personnel will be able to break the blockage, ending the backup. If there is not a cleanout, or if the cleanout cannot be located, you will need to call a plumber to assist you. If you call a plumber first and the blockage is caused by the city, you will be responsible for payment to the plumber. If you do not have a cleanout, you are responsible for clearing blockages from your home to the city main in the street.