What would cause blue stains and a blue tint to our bathroom tub and sink have water purification system in use for aprox. 7 yrs. Does this need any maintence
Blue or blue-green stains in fixtures is a sign of reduced copper. The source of this can be in the water itself (usually well water) or from the plumbing, usually caused by a very low pH (acidic water) which causes deterioration of the plumbing.
This is an article describing the problem. You should get the water tested and have a qualified water treatment specialist or plumber come up with a plan to address it.
Since you already have a water treatment system, it may just be out of balance. In general, these systems require regular maintenance (flushing and changing of catalysts/chemicals).
Get it fixed. It's a health issue.