The provisions of this section of Part 9 in the 2002 BSS Standards are mandatory for non-private boats where applicable.

Any sewage discharge into a watercourse is offensive and is usually illegal. To minimise the risk of a boat's toilet system creating pollution, it is recommended that toilet systems that discharge human waste directly into the water can be sealed off.

Sealing a toilet system can usually be achieved by either sealing the sea-cock in a closed position or by fixing heavy-duty tape over the bowl or lid of the appliance. To minimise pollution, and the risk of the holding tank imploding, it is recommended that the toilet system is constructed to a recognised Standard, i.e. BS EN ISO 8099.

If large quantities of fuel or other substances escape into a watercourse you should contact the Environment Agency Pollution Hotline on 0800 80 70 60 (24hrs) or the Scottish Environment Protection Agency on 0345 73 72 71. [9.1]

Owners of boats based in, or visiting, an inland waterway are advised to check with the relevant navigation authority concerning any restriction in place in respect of sea toilets capable of discharging directly overboard. Examiners are not required to render sea toilets inoperable, however some navigation authorities require owners to inform them of the presence of sea toilets.