In the steady state, water intake (including that generated from endogenous metabolism) must equal water output. There is no such thing as ‘normal’ maintenance or ‘half’ maintenance fluids in renal failure as well as in general. Maintenance fluid is the fluid required to keep a subject in homeostasis or steady state. Therefore, maintenance fluid is the fluid required to replace the daily loses. The body responds to a water load by suppressing anti-diuretic hormone (ADH) secretion, resulting in decreased collecting tubule water reabsorption and excretion of the excess water. Hyponatremia involves disorders of sodium concentration are common clinical problems. These disorders (hypo- and hyper-natremia) reflect abnormalities in water content of body and not necessarily in sodium balance itself. Hyponatremia can result from either solute loss or water retention.