So now after eight pages we finally get a little insight of what you can bring to the table to achieve this endeavor of financial stability while living in Mexico. Sales, construction, and some other things, and of course enthusiasm. C'mon, there's got to be more than that. But to keep in the spirit of this thread, I will give you my Pie-in-the-sky idea.
As I stay in Cholla, this idea is based for that area. The thing I notice most about Cholla is sand. Sand in your car, sand in your house, sand in your swim trunks. But sand in your potable water is the most annoying. Being Cholla must have a building code that states, " All water supply and service lines must also have a dual purpose of hanging laundry from", it seems to me developing an inline filter would be a popular idea, easy to install, not to mention inexpensive. It would consist of 4" diameter ABS pipe, inserted with a 60-80 PPI reticulated polyurethane based foam, capped and a check valve to dispense the sand. If I had to guess, a complete unit would cost $40.00 to $60.00 to manufacture. There ya go, run with it. Feel free to call Pie-In-the-sky inline filter Co. if you'd like.