I started my 100 gallon reef in 1971 with water from the East River that goes past Manhattan. That was 43 years ago, so far I have not had any problems except of course the corals try to grow up the walls and stain my ceiling and the fish keep spawning, even the 24 year olds so I don't have room for the fry.
I do own a boat but I never use it to collect water. I don't have a tuck but can easily put 20 gallons in my PT Cruiser. I use five gallon water bottles that I find in lots, they are the same ones on top of office water coolers but I used to use five gallon buckets. To collect the water I don't go to far offshore. Usually about five feet from the sand or up to my knees is enough as long as it is deep enough to fill a bucket. To prepare the water, I put it in my house, let it warm up to the tank temperature which could take a while because here in the winter there is ice cubes in the water, then I dump it in. If it has seaweed, jelly fish, bugs or rusty pieces from a 1956 Oldsmobile in it, I strain it through a coffee filter or pillow case, then I dump it in. Am I bad?
I collect it here. Yes, that's snow on the beach.