17th century
Wastewater from sinks and washtubs was disposed into simple culverts or wooden pipes that flowed downhill into tidewater.

Outhouses (bathroom) waste was buried into the ground which seeped into drinking water wells, making people sick with cholera and other diseases.

Late 1800s
A commission was formed to investigate the problem of disease-causing sewer back-ups. The commission recommended that the untreated sewage be discharged into the ocean, far away from people's homes. Two physical systems were developed which drained into ocean locations where the tide was strong enough to carry away the discharged sewage. One system discharged near Deer Island, the other near Moon Island.

Mid 1800s
Homes began to install water closets (a room containing a toilet and often a washbowl) that emptied into primitive and leaky sewers.

1889
The Metropolitan Sewerage Commission was formed to manage the sewers in Boston and the Cambridge area.

1904
Additional communities were incorporated into the Metropolitan Sewerage District, sewage discharge were diverted to Nut Island in Quincy, MA. By this time, there were three independent locations for collecting, screening, and disposing sewage into the Boston Harbor.

1939
More than 250 million gallons of raw sewage was disposed into Boston Harbor EACH day, causing a major pollution problem in the harbor. This prompted a recommendation to construct primary treatment facilities at the discharge locations.

1952
Boston's first primary wastewater treatment plant opened on Nut Island to serve the communities south of Boston.* Sewage discharges flow into the shallow waters of Quincy Bay.

1968
The Deer Island primary wastewater treatment plant opened. All flows from Moon Island were diverted to Deer Island * instead of constructing a third wastewater facility.

Early 1970s
15-20% of the sludge discharged with the outgoing tides returned near the harbor's shore areas with the next incoming tide. As a result, Boston Harbor became severely polluted.

1984
Due to sewage pollution on Quincy's beaches, the city of Quincy filed a law suit in the state court against the Metropolitan District Commission (MDC). Massachusetts Water Resources Authority (MWRA) was created to manage the clean up of Boston Harbor.

1985
MWRA assumed responsibility for water and sewerage systems from MDC which was below federal standards for wastewater treatment. Therefore, a federal court mandated the creation of a new wastewater treatment plant which would become the Boston Harbor Project, a $3.8 million project to help protect the harbor from future sewage pollution.

1989
The discharge of scum (floatable pollution such as grease, oil, and plastics) is halted at both Deer Island and Nut Island treatment plants.

1991
The Sludge-to-Fertilizer facility is completed, allowing the MWRA to discontinue sludge discharge into Boston Harbor.

1995
A new primary treatment plant at Deer Island is completed, improving the system's overall capacity and the effectiveness in its treatments.

1997
First phase of Secondary Treatment Plant at Deer Island is completed. For the first time, the plant meet the requirements of the federal Clean Water Act.

1998
Nut Island Treatment Plant is closed and wastewater flow from MWRA's South Shore communities is transferred to the Deer Island plant. Start up of secondary battery of secondary treatment at Deer Island plant begins.

2000
MWRA's treated wastewater is discharged into the deeper waters of Massachusetts Bay through a new outfall tunnel and diffuser system, ending the discharge into the waters of Boston Harbor. Construction of third and final battery of secondary treatment at Deer Island plant is completed.

*These two facilities included grit and screening removal, primary sedimentation, chlorination, sludge digestion, and discharge to the harbor on the outgoing tide.