I just thought of something. Where did you get the water hook up? I guess you would need to convince a business to allow you to use their water huh?
It's odd, I don't really see replies from anyone who's actually USED a "charity" car wash. Am I the only one?
1) tywebb: they use companies that have parking lots with landscaping. Lots of landscaping = a hose connection SOMEWHERE, regardless of sprinkler setup. McieDees is the popular one around here
2) I used to use the charity parking lot washes and Man, what a great wash! And for $5! I pulled over almost every time. Auto washes around here are $8 for a water spray and up to $19 for the "Triple Super Fantastic Blue Coral RainX BlowJ" so the $5 was a bargain. Most of the outfits were local school athletics. Used to be a variety of girls and boys of all looks and sizes, then mainly girls of all looks and sizes. There also used to be a smattering of mom and dad-looking types talking to drivers and collecting the money. Local-looking, frumpy folks.
The last several times I've seen a parking lot wash it's been scantily-dressed teens hopping around the side of a road like cheerleaders, with tough guys running the cash and I don't stop anymore. It's just creepy. Short, trim, cute girls while the guys are tall and beefy and wear gold chains. In a real athletics program there are tall and short, ugly and attractive. WTF is this?
That's all to say that IMHO the more straightforward way is the better method. Don't fake a charity or cause. You can make bank giving people $5 car washes but keep it simple, don't over-burden your backstory. The shady ones popping up around here are either protected, connected, or are going to have their heads handed to them by the deputy dawgs. Standing out in public in a riskier pursuit than online dodges