California, USA, is planning to introduce a toilet-to-tap programme to solve the prevailing water shortage problem in the state. The planned project will include a three-year trial period during which about nine million gallons of wastewater will be processed every day at the Donald C Tillman Water Reclamation Plant at the Sepulveda basin. The water will then be transferred into potable water aquifers for filtration. Five years later, it will be withdrawn, after being filtered naturally.

Using reclaimed water as a substitute for potable water is not a new concept for the state. Currently, some 40 cities use reclaimed wastewater for urban sanitary purposes, but not for human consumption. Supporters of the project claim that natural filtration along with application of chemical disinfecting techniques, provides reclaimed water that is cleaner than regular tap water. But a few are apprehensive about such claims. They say that the planned method does not include any process for removing trace organic contaminant, which is a dangerous omission ( Environmental Health Perspectives , Vol 108, No 10).