Low urine specific gravity may be caused by physiological reasons, but it may also be caused by chronic glomerulonephritis, tubular injury and other pathological reasons. 1. Physiological reasons: if you drink too much water in a short period of time, the proportion of water in the urine will be high due to the increase of urine filtered out by the kidneys, while other components will be reduced accordingly, so there will be physiological low urine specific gravity phenomenon. 2. Pathological reasons: chronic glomerulonephritis, renal tubular injury, pyelonephritis, renal failure and other renal diseases involve the renal tubules, which can damage the concentration function of the renal tubules. When the concentration function of renal tubules is reduced, urine cannot be concentrated normally, thus showing low specific gravity. When you find low specific gravity of urine, it is recommended to go to nephrology department in time for further examination, to clarify the cause of the disease, and follow the doctor’s instructions for symptomatic treatment.