Question: How are sewer rates set?

Answer: Water that is used in a home or industry is flushed through a building's pipes until it reaches local sewers. From there the wastewater is transported into the MWRA interceptor sewers, having collected sewerage from western communities. Meters record flows and volume before the sewerage goes into Somerville’s sewers and again when the City’s lines dump into these interceptor lines in order to determine Somerville’s portion of the total. The interceptor sewers, ranging from 8 inches to 11 feet in diameter, carry the region's wastewater to MWRA treatment plants. The treatment process includes passage through a grits chamber, a primary treatment tank to where sludge is settled out, and a secondary treatment tank to remove human waste and toxic chemicals. This process is very expensive. Click here.