How far apart must cleanouts be installed for horizontal sanitary drain lines that are 4-inches in diameter or less?

For horizontal sanitary drain lines that are 4 inches in diameter or less, cleanouts must be installed at intervals not exceeding 50 feet. This requirement is established to ensure that the system can be effectively cleaned and maintained without excessive effort or cost. Cleanouts provide access points where blockages can be removed and facilitate easy inspection of the drain line.

Installing cleanouts at this specified distance helps prevent long runs without access, which can lead to complications when maintenance is needed. By having cleanouts positioned conveniently, plumbers can perform their work efficiently and minimize disruption for homeowners or property management.

In this context, the choice of 50 feet aligns with plumbing codes and best practices designed to promote proper drainage and maintenance of sanitary systems.