Reuse and efficient ...

Reuse and efficient conservation. The problem is due to population growth in areas that have limited water availability. Water suppliers and governments  historically dealt with adequate supply with impoundments, canals, long pipelines, reservoirs. Now that water recycling technology is readily available (and desalination of seawater and brackish groundwater) they have more tools available. It is all in the planning for future population demand growth. Most importantly-charge appropriate water rates so that the water supplier is funded and the users are not subsidized and wasteful.