Holding Tank

A holding tank is a sealed onboard tank that stores sewage from the marine toilet, and sometimes grey water, until it can be discharged legally or pumped out ashore. It is part of the boat’s sanitation system, with hoses, valves, vents and deck fittings designed to contain waste safely and prevent odours or leaks.

Capacity matters on any cruise because a full tank can make the head unusable and may limit where you can anchor, enter a marina, or continue a passage. Crews should plan pump-out stops alongside fuel, water and provisions, especially when using the Head, Galley and overnight Offshore routines with several people aboard.

Good holding-tank management includes monitoring level gauges, keeping vents clear, using suitable paper and treatments, and understanding local discharge rules. PredictWind routing and forecasts can help choose favourable weather windows for marina calls or coastal stops where pump-out facilities are available.