The Water and Sewer Division of the Wellesley Department of Public Works operates and maintains the town's water and sewer systems. It is organized into two programs, which are funded entirely by the water and sewer rate payers. The department's address was changed to 20 Municipal Way from 455 Worcester St. when the current, new building was built. The new facility was finished in August of 2009. 

The department handles calls for issues stemming from water and sewer lines. A watchman is posted at the department after hours to relay emergency messages to department members who are on call. Surface water flooding calls, such as flooding caused by storms, are handled by the Wellesley Fire Department. This division is run by Superintendent Joseph B. Duggan.