How much does a gallon of sewage approximately weigh?

The approximate weight of a gallon of sewage is typically around 8 pounds. This is based on the general principle that a gallon of liquid water weighs about 8.34 pounds. Sewage, which consists of a mixture of water and various solid and liquid waste materials, can have a density close to that of water. The variations in density due to the different contents in sewage can result in only slight deviations from this weight. Therefore, estimating 8 pounds is a reasonable approximation, as it reflects common industry understanding related to fluid weights in systems and plumbing.