Of course we all come from different boating backgrounds. I didn't have the same experience as Bill did as a kid--but people certainly did pump sewage overboard in anchorages in S. Calif. Although EPA may have given the federal "teeth" in law, it was the State of Calif. which requested the first non discharge zones in 1975 (when I was still living in Huntington Harbor). Fast Forward, there are still multiple waterfront homes which are on inadequate septic (systems which contaminate the bays and waterways) in our part of Florida, despite full compliance of the boaters.
For example our subdivision had sewers installed about 6 years ago. The next subdivision up the bay still does not have sewer, even though they are less than a mile from a treatment plant which treats sewage to a level above Tertiary treatment and close to drinking water standards! Reason--the homeowners did not way to pay for the lift stations necessary--and they are not required to.
The Pensacola area, finally moved its primary sewage treatment plant (over 25 million gallons a day) from right down town with discharge into Pensacola Bay, and with occasional raw sewage discharge--no EPA regs against that during storm events! Fortunately the new plant is also beyond Tertiary treatment and then is allowed to perk back into the ground water or reused. Consider that some of our neighbors to the Direct North and South of the US still discharge huge volumes of raw Sewage directly into the ocean.
Another problem--and it goes to the question about industerial pollution. There was a huge amount of pollution going back over 100 years--folks just didn't think about it? The Superfund program was started in 1986 and industry paid a certain portion into the program for clean up each year. That program was not renewed, and EPA is basically out of money for clean up of Superfund Sites. There is still a bloated infrastructure in EPA left over from this program which left many clean ups only partially finished. Again, local pressure on EPA is what obtained grants to clean up the sites---some of which EPA did not even have on their books.
Todays laws are to hopefully prevent further contamination and keep our boating waters cleaner. However, there are still polluters who go unchecked because of the politics. I have mentioned it before--but there is a paper mill not far from where I live, which has been in "violation" for many years--and pays a $500 or so a day fine--cost of doing business--to pollute. State laws can be more restrictive, but local politics enter in there!
On the other hand, much of the polution has been cleaned up by organizations such as River Keepers and Surfriders. Sometimes I may not agree with some politics involved, but these organizations all do a lot to clean up the environment. It also boils down to what each of us do as boaters to keep our environment clean.