To ask the Scottish Executive whether it has established from Scottish Water how many development sites in local plans are constrained by a lack of water and sewerage infrastructure and whether it will provide an estimate of the number of houses which could be provided on established housing land supplies which are rendered non-effective by such constraints, in total and broken down by local authority area, what proportion of housing land supply sites will be rendered effective by the £167 million given to Scottish Water for removing constraints arising from a lack of “strategic infrastructure” and how many houses could be provided on these sites.