You can have clean water when you stop tearing apart the water treatment plants for the resale value of the previous water treatment plant.
or , here's an idea, enter the 21st centruy and collect taxes to pay for it yourself, like the rest of the country's municipalities?

Or, maybe the chiefs can forgo new trucks every year and actually build infrastructure for their people?

It's hard to keep the sympathy when all I can see on the res is complete corruption.

if the tribes are "their own nation" then maybe start collecting taxes like every other nation on earth?