Louisville’s Metropolitan Sewer District board has approved a 20 percent rate increase.

The board’s Finance Committee and full board endorsed the proposal Monday. The move would increase the average residential customer’s bill from just over $49 a month to nearly $59 a month.

Some of the rate increase is due to higher-than-expected capital spending for MSD to comply with an $850 federal consent decree to reduce discharges into the Ohio River.

The board has raised rates every year for the past decade, but except for a substantial jump in 2007, the rate increases were generally between 5 and 7 percent. Any rate increase larger than 7 percent also requires approval by the Metro Council.

A presentation to the council on the agency’s financial plans is scheduled for June.