(1) Governments such as those in much of Africa and all of the Middle East/Muslim South Asia are incapable of sustaining the development of even the simple well by well water treatment methods that have long been available. Due to violence and corruption any monies for development are better used in campfires to cook food.
(2) Our European "friends" would expect the USA to foot the bill but hire their "experts".
(3) The other demands of the Enviro-wackos, if implimented, make clean water useless as the poor would already starve before the water systems could be built
This is why the Bush admin is busily reforming economic aid distribution, channeling much of it through government/industry partnerships. The uber-idea is for aid to use and synergize with (and as developing countries prosper, to be replaced by) normal channels of capital flow as much as possible. This will tend to keep the money out of the hands of the global poverty pimps. It will also render programs more effective, to the point where they might actually solve problems rather than perpetuate them. The poverty pimps HATE this whole scheme (part of the reason why Powell was shouted down at the WSSD as he highlighted such programs).