The Washington Suburban Sanitary Commission is proposing a 7.5 percent increase to water and sewer rates for Montgomery and Prince George’s residents, according to WSSC officials.

In a letter to both county governments, commission Chairman Roscoe M. Moore Jr. said his agency needs a 22.3 percent increase to its capital and operating budgets. For customers who use about 210 gallons of water a day, the rate increase would be about $5 a month, Moore wrote.

If the WSSC’s budget is approved by both county councils, customers would see about a 35 percent increase in water and sewer rates from fiscal 2009.

The proposed increase is not as bad as it could have been. Legislators from both counties approved an increase of up to 8.5 percent. Moore said the 10 percent of the revenue from the rate increase will go toward a 2 percent cost-of-living raise and merit increases for all WSSC employees.

This post has been updated since it was first published.