Would pressure-washing using sea water be viable? If it's all going into storm water drains and out to sea anyway, what's the difference? Or does it go via, e.g

Would pressure-washing using sea water be viable? If it's all going into storm water drains and out to sea anyway, what's the difference? Or does it go via, e.g., sewage treatment, first? (I suppose this is a bit of a lazy question, but I couldn't easily find anything conclusive when I searched, and I bet there are interesting angles on the idea that I haven't even considered.)