I haven't been inspected (yet), but as I understand it, one of the things that the USCG will look for during any boarding, routine or otherwise, is the status of your marine sanitation system and whether or not it is in compliance. For those of with a simple toilet with the potential for overboard discharge, with or without holding tank, they will want to see that the seacock or valves that would allow overboard discharge have been secured and locked in the closed position. While a padlock would be ideal, apparently a zip-tie to a strong point that prevents one from opening the valve is sufficient.

FWIW, we need to keep in mind the differences between different types of marine sanitation systems -- most of us probably have the simpler type: a holding tank. We are not allowed to discharge wastes within the 3-mile limit, regardless of whether the area is a no-discharge zone or not. Some boats actually have treatment systems. Boats with these types of systems are allowed to discharge treated wastes within the 3-mile limit. The no-discharge zones are meant to apply to these boats (the ones with treatment systems). The rest of us are already prohibited from discharging our waste.

Now for the story: To set the stage, you need to know that, back in the day, my dad worked for the New Hampshire Water Supply and Pollution Control Commission (now part of the Department of Environmental Services). So we, a family of five, were cruising well down east in Maine, aboard our Paceship PY23. We had a porta-potty, otherwise known as a re-circulating chemical toilet. The thing had gotten full (there were five of us, afterall) so Dad inquired at a lobster dock whether or not there was anyplace around where we could empty the porta-potty. The fellow on the dock pointed out between the islands to the ocean beyond, and said " Don't pay no nevermind to them long-haired environmentalists, but there's a gawd-awful lot of water out there!" Well, my Dad didn't have long hair, but he was definitley an environmentalist. But that's what we did -- sail out beyond the islands, and dump the thing overboard (chemicals and all).