California is moving forward with rules for how water districts can turn what goes down your toilet back into drinking water. State regulators are taking comments on a kind of water recycling where wastewater sits in a lake before being treated. Next up might be a way to skip the wait. The state already has rules in place for groundwater recharge – where wastewater goes in an aquifer and later comes out for drinking water. Randy Barnard heads the recycled-water unit for the State Water Resources Control Board. He says both aquifers and surface reservoirs act as ‘environmental buffers,’ killing pathogens and diluting chemicals.