You can always bring in up in the JMB meetings.
However, one thing to consider - i.e. who's going to pay for the water usage if there's a designated "pipe" for waters.

Thus usually someone would need to bring up the notion and bring in someone to wash thus a car wash business is set up within the compound.

That's my opinion.

That's a good question, but am not really sure.
However, it's usually stated in an agreement what sort of amenities and maintenance you're paying for with the monthly maintenance fee. Be it issued by the maintenance office and could be amended when the JMB is in force. The nitty gritty am not sure, but usually that's the case. Thus the need of justification whenever there's a raise in maintenance fee collections.

There's a pinned "lawyer consultation" topic by dariofoo, maybe you can ask about whether there's any legality implication in the collection of maintenance fees.

Yes pls share once you get the information.