The following were among actions taken at Tuesday's meeting of the Prince George's County Council. For more information, call 952-5182.

PROPERTY TAX CREDIT -- The Prince George's County Council voted unanimously to reduce property tax bills of homeowners whose annual assessments increase by more than 10 percent.

Currently, property owners whose assessments increase more than 15 percent over the previous year are taxed at a maximum increase of 15 percent. Beginning in July 1991, the maximum increase in assessments they will have to pay will be 10 percent.

For example, under the current program, a homeowner whose property assessment increased from $50,0000 to $60,000 in one year, an increase of $10,000 or 20 percent, would pay taxes as though the house were valued at $57,500 -- a 15 percent increase. Under the new legislation, the house would be taxed only for a 10 percent increase, or as though it were valued at $55,000.

County property taxes are determined by taking the value of a residence and its surrounding land, multiplying it by 40 percent to determine the property's assessed value and assigning an assessment of $2.40 per $100 of assessed value.

It is estimated the change in the property tax credit program will cost the county $1.7 million over the next three years.

TEEN SUBSTANCE ABUSE FACILITY -- The council approved construction of an adolescent substance abuse facility on a 6.3-acre site on the grounds of Prince George's Hospital Center in Cheverly. The 40-bed unit will cost its owners, Dimensions Health Corp., $2.6 million to construct. An October 1991 opening date is planned.

The charge for youths who enter the 45-day substance abuse program will be on a sliding-fee scale based on ability to pay. The county also has agreed to pay for some indigent patients.

GLENN DALE HOSPITAL PURCHASE -- The council authorized the Maryland-National Capital Park and Planning Commission to purchase the 209-acre Glenn Dale Hospital site from the District of Columbia for $3.95 million. The site, formerly a tuberculosis sanitarium, is located at Annapolis and Glenn Dale roads near Bowie. The county does not intend to develop the land in response to neighbors' concern that it be kept as open space.

911 FEE INCREASE -- In a 6-to-1 vote, with council member Sue Mills voting in opposition, the council agreed to raise the monthly fee for providing the 911 Emergency Telephone System from 30 cents to 50 cents to make up for a shortfall in funds from the state. Mills said the rate hike was too steep.

Currently, county residents are charged 30 cents a month on their C & P Telephone bill for the 911 service. A recently passed state law requires state officials, who used to turn the entire 30 cents back to the county, to begin withholding 10 cents for a fund that will be used to ensure all counties in the state have and maintain an up-to-date 911 system. The increase becomes effective Jan. 1.