Toilet to Tap

San Diego imports about 90% of its municipal water from hundreds of miles away, mainly from the Colorado River and Northern California. Both sources are becoming less and less reliable as a result of competition and a decade-long drought. As a result, local politicians recently approved a pilot program for "toilet-to-tap" recycling.

San Diego already has two plants that recycle effluent for non-culinary uses like irrigation and manufacturing. But the city has not been able to find enough customers, so the plants are operating below capacity. The new plan calls for treating recycled water even further and then pumping it into a local reservoir where it will enter the primary supply. In theory, what comes out of the tap should be just as pure as water that has moved through the entire natural cycle of evaporation, precipitation, and biological and geological filtering.

In fact, given the levels of pollution in the Colorado River, toilet-to-tap water might even be purer than the existing supply. Las Vegas dumps roughly 60 billion gallons of wastewater a year into the Colorado. Samples from Lake Mead contain "prescription and over-the-counter pharmaceuticals, caffeine, sunscreen, synthetic compounds used in plastics and detergents, and even methamphetamines...." San Diego's supply contains "small but measurable quantities of ibuprofen, the insect repellent DEET, and the anti-anxiety drug meprobamate" before it goes through treatment to become drinking water. City planners argue that they will have control of reclaimed water through its entire life-cycle, rather than dealing the effects of this upstream pollution.

On the other hand, water treatment is a notoriously difficult process to get right, especially in an era of deregulated utilities, shrinking municipal budgets, and privatization. San Diego sees regular accidental spills, in which millions of gallons of raw sewage flood the area's lagoons and the ocean. And monitoring regularly discloses elevated levels of synthetic chemicals and medical compounds in the recycled water discharged from treatment plants around the country.

Toilet to Tap Takes Flight
Facing the Yuck Factor (HCN)