How long it takes for hydronephrosis to affect kidney function mainly depends on the cause of hydronephrosis and the degree of hydronephrosis. Generally, severe hydronephrosis may affect kidney function in 1 to 2 weeks to several months. Different states of hydronephrosis have different effects on renal function, mainly according to the severity of hydronephrosis. Hydronephrosis caused by complete acute obstruction affects renal function more quickly; hydronephrosis caused by incomplete obstruction progresses slowly. 1. Complete obstruction: mainly due to stone-induced postrenal obstruction causing hydronephrosis, resulting in increased pressure in the renal pelvis; when the pressure lasts for a long time, renal filtration dysfunction will occur, and even filtration reflux and so on; ultimately leading to the destruction of the glomerular tubules, and the emergence of renal insufficiency; usually the kidney has reached the degree of irreversible damage after 1-2 weeks. 2. Incomplete obstruction: usually the symptoms are mild to moderate, the damage to the kidney is not obvious, and the kidney will be seriously and irreversibly damaged in a few months. If you are diagnosed with hydronephrosis, it is recommended to have standardized treatment as early as possible to reduce the adverse effects of the disease.