Special purpose buildings and properties in Mercer Island (WA) have limited use of types of business that can be practiced on its premises. This may be due to strict Mercer Island (WA) zoning laws, the building's layout and design, and the owner's wishes to keep the premises unchanged from its original design and purpose. For example, a Mercer Island (WA) church may not be turned into a cafe, but can be used for a private school or house of worship.