In 2017 a new No-Discharge Zone (NDZ) was established in the Puget Sound. In stead of allowing discharge of treated wastes 3 miles from shore now there will be none. The local cruisers feel they have been demonized, but in reality it is the cruise ships that were targeted.
The Puget sound is unique in that it is the ONLY large bay where the 3-mile rule applied. All other bays (Chesapeake, San Fransisco, etc.) are considered inland waters, and all discharge of untreated waste is banned, whether 3 miles from shore or not. But the Puget sound is shared with Canada and is thus not the inland waters of the US.
Because the navigable waters are regulated by the federal government, the state has no authority to regulate discharges from boats, OTHER than requesting NDZ status from the EPA, which is quite easy, so the Washington state EPA had only one option; NDZ status.
NDZs began with the Clean Water Act (CWA) in 1972. They are often seen as political statements.
I'm not seeing a correlation with presidential party affiliations. There was a predictable burst when the law passed, no interest nearly a decade, and then a pretty steady rate since. The last Bush administration implemented 4 more NDZs than the Obama administration. If there are politics, they are local in nature and consistent.
Perhaps the rate is now declining, as the map gets filled in.
Interestingly, the Friends of the Earth petitioned the EPA in 2010 to allow several popular high-efficiency treatment systems, arguing they were better for the environment than a ban. How about them apples? It seems they believe that good treatment is better than the cheating that otherwise takes place. Rather like ethanol gas, the full cost of the regulation and the unintended consequences are not always considered. In this case, however, I think it is more a matter of the convoluted nature of regulations; the Washington EPA saw NDZ as the only available option.
Sadly, I don't think the effectiveness of treatment systems, such as the Rairitan Electroscan, is well understood.