Google Custom Search Engine is a search engine that can be customized to search only a number of specified sites, or the whole web with emphasis on the specified sites. I have created two CSE's to experiment with it. More more info, see the Google CSE Overview.
The WASH Search Engine searches the entire web but emphasizes included sites. Currently, these are all sites in the WATSAN portal, but more can be added. To add sites, contact Harry to become a contributor.
The WATSAN Search Engines searches all sites in the WATSAN Portal.