The Basin was part of The Bathroom Update (See also Toilet, Shower and Bin).
The Basin will fill itself using a water source block under the block it is placed on when right clicked with either an empty hand or an empty bucket. If there is not a source block it will display the message "You need to have a water source under the block the basin is on to fill it." Be warned: the source block will be removed every time the basin is filled in this way. (That's why you should normally use an infinite water source for the Basin and the Bath.) When full, you can also fill up an empty bucket to obtain a water bucket. The textures used are Quartz Blocks for the basin and Cyan Stained Clay for the faucet and handles.