Clean Water Plan

Each year, approximately 9 billion gallons of wastewater overflow into our region’s waterways. Because of that, ALCOSAN is not in compliance with the federal Clean Water Act.

To fix this, ALCOSAN has started a $2 billion, long-term, Clean Water Plan that will reduce the amount of combined sewage overflow by 7 billion gallons per year and eliminate sanitary sewage overflows. To achieve this, ALCOSAN’s plan involves four major components:

  • Regionalization - ALCOSAN is working with municipalities to take ownership of trunk sewers and related facilities to create a streamlined collection system.
  • Plant Expansion - The Clean Water Plan calls for ALCOSAN's Northside plant to expand. This additional capacity will help reduce the number of overflows caused by excess stormwater.
  • Regional Tunnel System - ALCOSAN will construct a new regional tunnel system made of three new deep tunnels, and related infrastructure, to allow more wastewater to travel to the treatment plant.
  • GROW/Source Control - ALCOSAN created the Green Revitalization of Our Waterways (GROW) program in an effort to reduce excess water from entering an already overloaded sewer collection system.

 


Clean Water Plan Timeline

ALCOSAN CWP Key Dates

Regionalization

Regionalization will more than double ALCOSAN’s sewer system ownership and maintenance responsibilities in the region.

265 Miles of Sewer

8 Wet weather control facilities

77 Diversion structures

Learn how ALCOSAN is working with municipalities to take ownership of trunk sewers and related facilities to create a streamlined system.

Learn More

Plant Expansion

The Clean Water Plan also calls for ALCOSAN's Northside plant to expand. This additional capacity will help reduce the number of overflows caused by excess stormwater.

Follow updates on ALCOSAN’s plant expansion plans.

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Regional Tunnel System

ALCOSAN will construct a new regional tunnel system, and related infrastructure, to streamline conveyance, or transport of wastewater to the treatment plant. This will help reduce overflows.

 

Ohio River Tunnel

100+ feet deep, 4.6 miles and 18 feet in diameter, with construction from 2025-2029.

Allegheny River Tunnel

100+ feet deep, 5.4 miles and 18 feet in diameter, to begin construction in 2028 and complete by 2034.

Monongahela River Tunnel

100+ feet deep, 5.3 miles and 18 feet in diameter, with construction from 2030-2036.

Learn about the changes at ALCOSAN that are underway to accommodate flow.

Take a Look

GROW/Source Control

ALCOSAN created the Green Revitalization of Our Waterways (GROW) program in an effort to reduce excess water from entering an already overloaded sewer collection system.

GROW program

Learn about the changes at ALCOSAN that are underway to accommodate flow.

Get the Facts

Resources

CWP Cover
CWP Documents

Looking for more technical information? All of our plans and formal documents may be found here.

Documents
Service Area Map
System Mapping

ALCOSAN makes mapping related to the regional sewer systems and our region’s waterways available to the public.

See Maps
overflows
Sewer Overflows

A combined sewer overflow (CSO) occurs when stormwater and untreated, diluted sewage, overload the sewer system and flow into rivers and streams.

Learn More