With a June 30 deadline to decide on an animal control program, the Mercer Island City Council unanimously voted to join an interlocal agreement with King County for its animal control services.

During the first six months of the agreement, the city may opt out, but after that Mercer Island must remain tied to the agreement for the next two years, said City Manager James Mason.

Twenty-seven other cities have already signed on, according to city documents. The final cost of the program won’t be known until June 30 and will be based on the number of participating cities.

Based on the current data, Mercer Island will pay approximately $1,375 for the remainder of 2010 and $2,875 for service in 2011.

The King County animal control service will include animal control, sheltering and licensing. The county plans to revise its code to encourage more pet owners to license their animals. In turn, the agreement requires Mercer Island to change its code to match the county’s in terms of license fees, penalties, enforcement, shelters, impound and redemption.

The updated code may result in higher licensing fees for owners, Mason said.

Licensing fees offset the cost of animal control for the city. In order to break even, the city needs to sell about 95 more licenses each year at the current rate.

The interlocal agreement with King County will begin July 1.