You should avoid toilets to be in Northeast corners as it is a severe vaastu dosha , it can creates severe problem in health, problems in progeny ,accidents, and can also brings unnecessary stress..
If toilet is attached in the bathroom itself then it should be in the the West or North-west side of the bathroom and preferably few inches above the ground.
North east is the most very pious direction in vastu and is owned by the Lord Shiva, Northeast is occupied by Vaastupurush’s forehead. So one should avoid the placement of the toilet/bathroom here.
Also Toilets in the Southeast direction should be avoided according to vaastu. The person living in the building which has southeast toilet have unexpected losses, legal issues, unexpected problems,accidents with electricity and problems in electricity gadgets as Southeast is owned byAgnidev .
Toilet in the southwest is also not good. The people have to bear financial issues, unnecessary expenses, losses,. South west is the area ruled by rahu; One should avoid drainage in this area as this will cause cronic health problems.
Toilets should be placed in such a way that they face the north or south and never in east or west.
One should avoid to make Toilet under the stairs. Similarly the toilet is not good in the centre area ( bramasthan) of the house.
Toilet should never be made near the puja room or the kitchen . Also the kitchen and the pooja room above the toilet is not vaastu friendly. Only a toilet can be made over the other toilets.
Water storage & taps should be in East, North or North-East.
One should preffer light colours in the toilet.
A Small window in the toilet should be on the East, West or North wall.