<span>A little bit more than three... pick and choose! Each kidney has about 1,000,000 filtering units, called nephrons. Roughly 40 gallons of blood in women and 48 gallons of blood in men are filtered each day. The colour of your urine can reflect if you are drinking enough water; it is usually light yellow if you are drinking enough water and dark yellow if you are not. For someone with kidney failure, it typically takes 4 hours of dialysis, 3 times a week to perform the filtering duties of normal kidneys. <span>The need to urinate is felt when about 1 cup of urine fills the bladder.</span></span>