US Patent 9157223 Lavatory system

A lavatory system includes a basin configured to receive at least one faucet, the basin defining a primary drain passage and first and second overflow drain passages; and an overflow adapter configured to be mounted to a rear surface of the basin, the overflow adapter defining an adapter passage such that when the overflow adapter is mounted to the basin, fluid received by way of the first overflow drain passage is directed through the adapter passage between the overflow adapter and the rear surface of the basin and to the second overflow drain passage.