Diluting urine decrease the urinary concentration of struvites and calcium oxalates. The larger urinary volume also ensure regular bladder wash-out.

Unsaturated urine is an environment where crystals cannot proliferate. Thus the urine is unfavourable to the development of struvite and calcium oxalate crystals.

Magnesium is a component of struvite (magnesium ammonium phosphate) uroliths.