a pumpout hose for a sewage tank
a pumpout hose for a sewage tank

Types of Marine Sanitation Devices (MSDs)

Types of MSD:

Type I

Type I is a an on-board treatment device using a physical/chemical based system that relies on maceration and chlorination. After treatment the treated waste can be discharged.

Type II

Type II is also an on-board treatment device that uses biological or aerobic digestion based system. After treatment the waste can be discharged. Type II systems are more often seen on large commercial vessels than recreational boats.

Type III

Type III is a holding tank or similar device that prevents the overboard discharge of treated or untreated sewage.

For Type III holding tanks:

  • Use enzyme deodorizers for holding tanks and portable toilets.
  • Pump out before you haul your boat for the winter.
  • Know where your closest pumpout stations are located, and height or draft restrictions, seasonal closures and hours of operation.
  • Consider using a pumpout boat service if one is offered in your area to make pumping out more convenient.