Holding tank

On the IMO site the revised MARPOL Annex IV applies to ships on international voyages of 400 gross tonnage or more, or certified for more than 15 persons. It also includes three equipment options: treatment, comminution with disinfection, or a holding tank. Discharge of comminuted and disinfected sewage is beyond three nautical miles from the nearest land. Untreated sewage from the tank is beyond twelve miles, under way at not less than four knots, at a rate the administration has approved. An ordinary pleasure yacht does not fall under this annex. The Baltic Special Area in the same text is about passenger ships and dates from 2019 to 2023. Those dates are not carried onto the card of a 10-metre boat.

What it is

A holding tank stores black water until a shore pump-out, or a discharge where the rules allow it. Whether the tank is mandatory depends on the waters and the flag: that district is checked on its own. A stubborn smell, soft hoses and a seized Y-valve are a cost of ownership. "We did not use it" does not cancel a hose change. The smell is more often the hoses and the ventilation, not a crack in the tank.

EU directive 2013/53, Annex I part A point 5.8, says something else. Any toilet on a recreational craft is connected only to a holding-tank system or to a treatment system. If a tank is fitted, a standard deck fitting for a shore pump-out is required. Pipes for human waste through the hull have valves that can be secured closed. That is a construction requirement, not a discharge distance.

HELCOM Annex IV, rule 5, pulls retention onto a pleasure craft with a toilet, if the craft does not fall under MARPOL Annex IV. A build before 2000 applies from 1 January 2005. A build from 2000 applies from the rule's entry into force. An exception is possible if the installation is technically difficult or expensive relative to the price of the boat, and the hull is from before 1 January 2000, and only in the waters of that contracting party. The German flag site says it plainly: Annex IV does not apply to recreational craft, but the national See-Umweltverhaltensverordnung, paragraph 9 on toilet waste, does apply. These pages do not give one mile that is common to the whole Baltic. HELCOM has to be carried by national law. A Swedish or Finnish ban is not substituted here in one line. Even with a shore pump-out, the Y-valve is still checked: it must not open to the sea where that is forbidden.

The miles from the annex for large ships do not fit an advert for a pleasure boat. Nearby on the site: thru-hull, seacocks, bilge pump and survey checklist are other pages, not this distance.