The urine specific gravity of 1.020 is normal in routine urine tests, and the specific gravity of urine is 1.010-1.030 under normal circumstances. abnormal changes in specific gravity can occur when patients have diseases or dehydration, concentrated urine, etc. The specific gravity of urine is how much heavier the urine is than water. If the same volume of water is considered as 1, the weight of the same volume of urine is 1.020, because there are toxin components in the metabolites of urine, so it is slightly heavier than water, but it is still water in the main body, so it is almost equal to the weight of water. When the body is infected, the bacterial metabolites in the urine and the number of white blood cells increases, which can then cause a situation where the specific gravity increases, i.e. the mass becomes larger. When the urine is concentrated or the water intake is insufficient and the water evaporates too much, the specific gravity of the urine will be increased appropriately, but when the metabolites of toxins are blocked, the urine will also be diluted and the specific gravity will be reduced.