The most common cause of hydronephrosis is due to kidney stones or ureteral stones blocking the urethra, leading to poor drainage of urine from the kidneys. Generally, if hydronephrosis occurs, the first step is to check the renal ultrasound and, if necessary, undergo cystography to determine the cause of the hydronephrosis.

If it is confirmed to be stones, it is important to check the size of the stones. If the stone is smaller than five millimeters, you can drink more water, exceeding 3000 milliliters per day. This can help flush the stones out through the urine by being more active and jumping around.

If the stone is relatively large, it may require extracorporeal shock wave lithotripsy or ureteroscopic stone removal. Generally, for hydronephrosis, it is still recommended to drink plenty of water and eat a light diet, avoiding spicy and irritating foods.