They're NOT discharging illegally...the limit IS just 3 miles. There are several US "territorial" limits...12 miles for some parts of MARPOL...either 9 or 12 for fishing...and 3 miles for sanitation. Somebody who didn't do his homework picked up the 9 mile limit and MISTAKENLY applied it to sanitation in the flyer.
However, if you go to page 12 in the FLORIDA STATUTE 327.53 MARINE SEWAGE DISCHARGE REGULATION, August 1999, Updated June 2007 Part VI. "Regulated Waters," which is the actual LAW that whoever wrote that bulletin is misquoting, you'll find the following:
"The federal regulations distinguish among types of water bodies and apply different discharge standards to each type of designated water body. These standards apply only to vessels on which a MSD has been installed.70 This zoning schematic imposes effluent limitation of regulated vessels, in addition to the performance standards required for certification and labeling. For instance, in freshwater zones and in state designated no discharge zones discharge is prohibited. In coastal waters out to three nautical miles discharge is allowed if the discharge meets effluent standards. In waters outside three nautical miles from shore discharge is permitted, subject to the rules imposed by international law under MARPOL."
And on page 17, you'll find this:
Thus, in waters outside three nautical miles of the coast vessels may operate and discharge without any marine sanitation devices. Since Type III MSDs are mere holding tanks, the Type III must be secured in a no discharge position in all waters out to three nautical miles. Type I and Type II MSDs may discharge out to three nautical miles (if not in a prohibition zone) if the effluent limit is met (no coli form counts greater than 200 per 100 milliliters and no suspended solids greater than 150).118
And then there's Federal law (33 CFR 159.3) which establishes the "3 mile limit" for sanitation in the whole US (only the feds--EPA--can change it...no state can):
"Territorial seas means the belt of the seas measured from the line of ordinary low water along that portion of the coast which is in direct contact with the open sea and the line marking the seaward limit of inland waters, and extending seaward a distance of 3 miles."
Together, all that leaves little doubt that the same "3 mile limit" that applies to the rest of the country also applies to FL waters. EXCEPT--The EPA granted FL's request to extend that limit in the FL Keys National Marine Sanctuary to 12 miles in the Gulf. It remains 3 miles on the Atlantic side.