My basement bathroom has been fininshed for about 3 years and once the new paint and grout smells went away all I could smell was verying degrees of a urine type smell. It is kept clean and I have tried all different types of cleaning supplies but the smell won't go away. The smell is so strong that I can not pin point exactly where it is coming from (ie tub toilet or sink). I was wondering if it is sewer gas and if so how do I fix it? Thanks

Sewer gas smells nothing like urine by my own experience. More like a house the day after boiling cabbage without the vent being used... combined with someone that passed wind and left the room.

You don't have any pets... do you?

Make sure all the traps are filled with water. Toilet bolted down? New wax ring installed when toilet replaced?