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How much blood do the kidneys filter each day?

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organs of the renal system — renal system disease Organs of the renal system.

The kidneys perform a vital role in maintaining bodily equilibrium by processing a significant volume of blood daily. On average, the kidneys filter approximately 1,800 litres (about 475 gallons) of blood every 24 hours.1

This process involves the glomerular filtration rate, where about 170 litres (45 gallons) of water are filtered from the bloodstream into the renal tubules each day. The vast majority of this fluid—roughly 168.5 litres—is reabsorbed by the tubules and returned to the blood, ensuring that only a small fraction is ultimately excreted as urine.1

Maintaining this filtration capacity is essential for health; in conditions such as chronic renal failure, the progressive destruction of nephrons leads to a significant decline in the kidney's ability to filter waste and regulate fluid balance.2