Sir. I have had to deal ...

Sir.

I have had to deal with similar situations previously.

The biggest problem is that new property developments overseas are very often totally uncontrolled! There seems to be a simple expectation that the responsible water utility has a duty to provide a water supply to any property.

This is partially true - But there are guidelines regarding 'reasonable' conditions.

To provide a potable water supply to high elevations, WILL require infrastructure reinforcement. This will generally involve pumps, new, often larger diameter mains, service reservoirs and additional water treatment. i.e. Capital Cost!

Who pays for this?

Harsh, but simple.... Build a property where a potable water supply is not currently available, then be prepared to pay for it.

In  the UK this is called an Infrastructure charge, which is commonly levied against all new properties.

Water Utilities World-Wide, are cash poor. They cannot continue to supply a quality product unless properly funded.