The county board may prescribe rules and regulations for the construction of privately owned artificial basins of water used for swimming or wading, which use or need external buttresses or which are dug into the ground, located on private residential property and intended for the use of the owner and guests. The county shall, however, exempt all municipalities located wholly or partly within the county where the municipal building code is equal to or of higher standard than the county regulation and where the local authorities are enforcing the municipal building code.