Boston Harbor cleanup (1985–2000)
A federal court order forced Massachusetts to build secondary treatment for Boston's sewage, which had discharged largely untreated into the harbor. The Massachusetts Water Resources Authority built the Deer Island plant and an outfall tunnel at a cost of about $3.8 billion.
The harbor's water quality improved sharply and beaches reopened.
The case became a template for court-ordered wastewater upgrades and for regional authorities building large plants under deadlines.
San Francisco faces a similar test: an old coastal plant, a legal permit deadline, and a retrofit that must proceed while the system operates.
