the hormone that controls the water balance in the body is anti-diuretic hormone (ADH). The hormone is synthesized by hypothalamus and secreted by the posterior pituitary.

The hormone that controls the electrolyte balance in the body is Aldosterone. It acts to regulate sodium levels inside the body by increasing active reabsorption of sodium. It is synthesized by zona glomerulosa cells of adrenal cortex in adrenal gland.

Both the hormones, ADH and Aldosterone increase reabsorption of water in kidney.