What color marking is used for potable water?

The use of blue markings for potable water is standard in plumbing practices. This designation is important for ensuring the correct identification of water lines that are safe for drinking and cooking, helping to prevent contamination or misuse of water sources. Properly identifying potable water lines with blue markings aids in maintaining public health and safety by clearly distinguishing them from non-potable systems, such as irrigation or wastewater lines, which may be marked with different colors to indicate their purpose.

While other colors have specific meanings in plumbing marking systems—red often indicates a fire protection system, green may be used for sewer systems or reclaimed water, and yellow typically designates gas lines—blue is universally recognized for potable water across many codes and regulations, including the Massachusetts Plumbing Code. This consistent use of color coding enhances communication and reduces the likelihood of mistakes during plumbing installations and maintenance.