The Washington Suburban Sanitary Commission this week recommended a 16 percent increase in water and sewer rates in Montgomery and Prince George's counties.

The proposed rate hike must be presented at a series of public hearings, and must be approved by both the Montgomery and the Prince George's county councils. If it is adopted, residents would see the increase in the quarterly water and sewer bills that go out July 1, 1982.

The new rate would raise the annual bill from roughly $231 to $268 for an average suburban Maryland family using about 250 gallons of water and sewer capacity daily, said WSSC public affairs officer Marjorie Johnson.

Johnson said the WSSC expects citizens to be angered by the size of the increase, but added that the higher rate is necessary to pay the operating costs of the commission, which provides water and sewer services to the two counties. The WSSC is barred by law from operating at a deficit.

"We have fixed costs over which we have no control," Johnson said. "The cost of heat, light and power are all going up. Chemical costs are skyrocketing."

The WSSC also floats bonds for its major construction projects, such as finished water storage units, sewage treatment plants and pumping stations. The cost of paying interest on those bonds remains high, Johnson said.

In 1980, the WSSC raised water and sewer rates 22 percent, but this year's increase, which took effect July 1, was only five percent. The WSSC staff recommended increasing rates for the coming year by 31 percent, but, over the objections of chairman Jesse L. Maury, the six-member commission voted 5-to-1 to recommend a 16 percent increase.

Public hearings on the proposed rate increase will be held by the WSSC on Feb. 3 and later by the county councils in both Montgomery and Prince George's. A joint session of the two county councils must agree on a final WSSC budget, and the commission will then set its rates to conform to that budget.

If the county council members believe a 16 percent rate increase is too much, they can effectively reduce or block the increase by cutting the overall WSSC budget, Maury said.