The board of directors of the Metro Sewer District will vote today on a proposed rate increase.The increase of 6.5 percent would raise rates a little more than two dollars a month for the average customer. Because the increase is under seven percent, it would not need Metro Council approval if it passes the MSD board. There will, however, be a public comment period between the board's vote and the time the rate increases in July.MSD officials say the higher rates are necessary for the district to make system improvements and be in line with the Clean Water Act.This would be the latest in a series of annual rate increases. The last two were also 6.5 percent.