Hi Brian - I can sympathise ...

Hi Brian - I can sympathise with your situation and some of your frustration. In terms of contracts, a charity I worked with used a "memorandum of understanding" to define the relationship between parties. It seems that the way money is routed is pretty key as well to ensure control. The setting up of a local water council to carry out and pay for ongoing maintenance is important . My small non-profit company WaterReach has developed a self washing filtration system which has no ongoing maintenance and uses local materials to build - thereby avoiding some of the issues you mention. Happy to share more about this if of interest. I attach a leaflet incase.