Is it okay to plant juniper shrubs over a septic tank?

I wouldn't plant anything over a septic tank. Nothing should be planted over the tile bed but grass.

Tick

I totally agree with Tickle on this. Never plant trees or shrubs over a tank or the field. The tank will need servicing eventually and the roots can cause cracks in the tank lid or line. The field needs to be free of all plant material that could seek the tiles and try to invade.