As a general rule, what is the minimum horizontal distance water pipes should be separated from sewer pipes?

The minimum horizontal distance that water pipes should be separated from sewer pipes is generally recommended to be 10 feet. This requirement is based on health and safety considerations, aiming to reduce the risk of contamination of the potable water supply from potential leaks or breaks in the sewer line.

Keeping a distance of 10 feet helps create a buffer zone that minimizes the likelihood of pathogens or contaminants moving from the sewer into the water supply system. This guideline is important for maintaining public health standards and ensuring the safety of drinking water.

While other distances may often be used in certain specific contexts—such as 5 feet or 7 feet—these do not provide the same level of safety and risk mitigation as the 10-foot separation. Regulations such as those from the American Water Works Association (AWWA) and the Environmental Protection Agency (EPA) endorse the 10-foot separation to help ensure a robust defense against contamination.