API Plan 65A is a leakage detection and collection system for single mechanical seals, designed to safely manage and monitor controlled seal leakage. It utilizes a gravity drain to route the leakage to a collection reservoir while incorporating an orifice and level switch for monitoring leakage rates.

This plan is ideal for applications where a small amount of leakage is expected and needs to be directed safely away from the pump. Unlike Plan 62, which uses external flushing, Plan 65A focuses on leakage monitoring rather than dilution or quenching.