The Metropolitan St. Louis Sewer District Board of Trustees gave unanimous final approval last week to a consent decree requiring billions of dollars worth of districtwide improvements over the next two decades.

Trustees voted at a June 29 special meeting to approve the consent decree, which outlines roughly $4.7 billion in infrastructure improvements and other mandates over the next 23 years.

The move is a step toward settling a 2007 lawsuit against MSD by the federal government on behalf of the Environmental Protection Agency and the state of Missouri on behalf of the Department of Natural Resources. The Missouri Coalition for the Environment later intervened.

Plaintiffs claimed in part that the district was discharging untreated sewage from its collection system through combined sewer overflows and constructed sanitary sewer overflows, a violation of the Clean Water Act of 1972. All parties except for the state have agreed to sign the consent decree, which will be filed with a federal judge and finalized in the coming months.

The district’s Rate Commission currently is considering a wastewater-rate increase proposal to fund a roughly $1 billion Capital Improvement and Replacement Plan, or CIRP, to bring the MSD system into compliance with state and federal regulations; $634 million in total operating costs over the next four years; and $359 million in total debt service.

As proposed, customers owning a single-family home would pay an average of $32.37 per month for wastewater services beginning July 1, 2012. That rate would increase to $36.71 per month in fiscal 2014, $41.56 per month in fiscal 2015 and $47.05 per month in fiscal 2016.

Commercial customers would be placed on a five-tier compliance charge system based on inspections and compliance samples. A typical monthly commercial wastewater bill would increase to $292.50 in fiscal 2013, $326.55 in fiscal 2014, $368.05 in fiscal 2015 and $409.80 in fiscal 2016.

MSD hopes to issue $945 million in bonds and use $171 million in cash to finance the CIRP.

Voters would have to approve the bond issue and may consider the measure in April.

If voters reject the bond issue, MSD may be left to fund the entire CIRP with cash, which officials said would cause the average single-family wastewater rate to increase to $73.35 per month in fiscal 2013.

However, officials have said the two scenarios are the “extremes” and that the Rate Commission could recommend higher or lower amounts of bond and cash usage.

The commission received the wastewater rate-increase proposal May 10 and has up to 165 days to make a recommendation to the Board of Trustees. The commission is expected to conduct public hearings throughout its deliberations to gather input from ratepayers.

Wastewater rates went up July 1, the last in a series of increases voters approved in April 2008. The average single-family’s monthly wastewater bill increased to $28.73 from $27.56. Commercial customers now will pay an average of $254.80 per month in fiscal 2012 — up from $244.25.

The Metropolitan St. Louis Sewer District Board of Trustees gave unanimous final approval last week to a consent decree requiring billions of dollars worth of districtwide improvements over the next two decades.

Trustees voted at a June 29 special meeting to approve the consent decree, which outlines roughly $4.7 billion in infrastructure improvements and other mandates over the next 23 years.

The move is a step toward settling a 2007 lawsuit against MSD by the federal government on behalf of the Environmental Protection Agency and the state of Missouri on behalf of the Department of Natural Resources. The Missouri Coalition for the Environment later intervened.

Plaintiffs claimed in part that the district was discharging untreated sewage from its collection system through combined sewer overflows and constructed sanitary sewer overflows, a violation of the Clean Water Act of 1972. All parties except for the state have agreed to sign the consent decree, which will be filed with a federal judge and finalized in the coming months.

The district’s Rate Commission currently is considering a wastewater-rate increase proposal to fund a roughly $1 billion Capital Improvement and Replacement Plan, or CIRP, to bring the MSD system into compliance with state and federal regulations; $634 million in total operating costs over the next four years; and $359 million in total debt service.

As proposed, customers owning a single-family home would pay an average of $32.37 per month for wastewater services beginning July 1, 2012. That rate would increase to $36.71 per month in fiscal 2014, $41.56 per month in fiscal 2015 and $47.05 per month in fiscal 2016.

Commercial customers would be placed on a five-tier compliance charge system based on inspections and compliance samples. A typical monthly commercial wastewater bill would increase to $292.50 in fiscal 2013, $326.55 in fiscal 2014, $368.05 in fiscal 2015 and $409.80 in fiscal 2016.

MSD hopes to issue $945 million in bonds and use $171 million in cash to finance the CIRP.

Voters would have to approve the bond issue and may consider the measure in April.

If voters reject the bond issue, MSD may be left to fund the entire CIRP with cash, which officials said would cause the average single-family wastewater rate to increase to $73.35 per month in fiscal 2013.

However, officials have said the two scenarios are the “extremes” and that the Rate Commission could recommend higher or lower amounts of bond and cash usage.

The commission received the wastewater rate-increase proposal May 10 and has up to 165 days to make a recommendation to the Board of Trustees. The commission is expected to conduct public hearings throughout its deliberations to gather input from ratepayers.

Wastewater rates went up July 1, the last in a series of increases voters approved in April 2008. The average single-family’s monthly wastewater bill increased to $28.73 from $27.56. Commercial customers now will pay an average of $254.80 per month in fiscal 2012 — up from $244.25.