Toilets should to be in the northwest of the house/building. Avoid constructing a toilet in the center of the building and in the northeast of the building. When it has to be an attached toilet, let it be to the northwest side of the room. The second alternative is the southeast of the building or room. An sample plan of a toilet interior is as under:

As northeast (eashanya) is the junction of Kubera and Indra, it is said that toilet in the north-east may gradually weaken the finances and the general prosperity of the master of the house. And, toilets in the southwest makes the master indecisive and his health may suffer.

Points To Remember:
Have the bigger window on the north and a smaller one in the west after providing for privacy.
Toilet seats from south to north or west to east are approved.
Mirrors in the toilet may be on the north and east walls.
Doors can be on the east of the north-east.
Let the walls be coloured using light shades. Avoid red and black color.