I do get spoiled living next to the ocean. Heading down to get some water now. But I do also make my own water. I built a 8 stage RODI system that would give me 150g+ if I needed it. but it is just really nice to fill a 5 gallon jug in less than 20 mins (temp depending) The NSW near me has a bit of extra things a my mix does not. For eg; it has a some phosphates (There are some natural heat vents nearby that has something to do with it) and no nitrates and on my 40 it seems my phosphates are always low so I can add that without raising nitrates.
I am grateful for where I live and like I said spoiled.
I live close to the ocean also. About a 30 minute drive, you're probably on the water? I am there a lot. I've always thought about bringing water back to put in the tank.