A second sink in the bathroom is like an extra pair of hands: You can always find a use for it. A double-sink vanity is a practical feature for large (or growing) families, or for a working couple whose morning routine would be vastly improved without the daily do-si-do at a single sink.
Custom Vanity
Adapting a piece of furniture like a farmhouse table or sideboard to serve as a vanity can have its limitations. In the photo at top, the two undermount sinks are set close together, there isn't a lot of countertop area and the level of the lavs is fixed by the height of the table. Still, a one-of-a-kind look like this can make an ordinary bathroom special.
Finding the Room. Of course, the extra plumbing and cabinetry for a second sink require space. To determine if your bath is a candidate for a second sink, chart out the room with a tape measure and graph paper, making a scale drawing of the space and all its fixtures so you can evaluate the possibilities.
The easiest way to accommodate a second sink is to expand your existing vanity area. There should be a maximum run of 30 inches between the centers of the two basins. This will allow you to tie the two sinks together with a single waste line. However, separate traps and drains are usually required if the vanity contains a stack of full-length drawers between the basins, because the pipes are blocked by the drawer boxes.
Even if you find the room to add another sink without reconfiguring other fixtures, you have some other space concerns to deal with. They include:
When a sink is opposite a tub or toilet, a minimum of 30 inches of open space should separate the fixtures.
Make sure there's at least 12 inches from the center of the sink to the nearest wall.
If you're moving a toilet to make more room, there should be at least 15 inches from the center of toilet to a wall or cabinet.
Leave room for the swing of the bathroom entry door, linen closet door or shower door. These are minimum measurements required by code; as always, check with the building department for other codes of this type in force in your community.
