Read the below on a forum. It does follow along with what I read for
Florida law that any vessel over 26' must have a working
head. Perhaps the porta potti needing a
holding tank is only for part of the keys? Going to have to
research further.
Quote from other forum post:
' FEDERAL
marine sanitation laws only apply to vessels with with installed toilets...and do not require any vessel that doesn't have a
toilet to install one.... EXCEPT for houseboats...which are defined in the CFR as any vessl that is used primarily as a residence and not as a means of transportation. States CAN make up their own rules pertaining to houseboats. So FL decided that every vessel 26' + is a "houseboat" and that all "houseboats" must have an installed
toilet and
holding tank and/or treatment device.
So you CAN have a portapotty...if the
boat is < 26' you can use a portable portapotty, wag bag or whatever...but if your boat is 26' or larger, at a minimum the portapotty has to be an MSD version--permanently installed and fitted for pumpout. Or a marine toilet, holding tank and all the related
plumbing. '