The distal convoluted tubule is located in the cortex. The filtrate entering the tube is dilute, having lost nearly all of its electrolytes in the ascending limb of the loop of Henle, as we have seen. Urea is the principal solute in the filtrate.

The distal convoluted tubule is one of the main sites of secretion. Additional wastes not filtered by the glomerulus are actively secreted into the distal convoluted tubule from the bloodstream. In addition, the distal convoluted tubule participates in the regulation of key electrolytes, such as potassium, sodium, and calcium. Potassium is secreted from the blood into the tubule, whereas sodium and calcium are reabsorbed from the tubule into the blood in response to hormones. Finally, the distal convoluted tubule helps to regulate blood pH: bicarbonate (HCO₃⁻) and protons (H+) are secreted into the tubule or reabsorbed out of it, as needed.

As a result, the filtrate leaving the distal convoluted tubule and entering the collecting ducts is dilute and contains mainly urea and other wastes.