Does anyone know what actually causes bladder stones? Could it be iron or calcium in the water supply? My gp is only 1 1/2 yrs. old, but I only give her filtered water (Brita system). The water here in Chicago is so bad, you can actually SMELL the chlorine when you turn on the tap! Maybe Dr. Dudman in the U.K. has some ideas? Good luck to all. Ty.