Coastkeeper Tours Groundwater Replenishment System

On June 25, the San Diego Coastkeeper Environmental Law Clinic staff and legal interns toured the Orange County Groundwater Replenishment System in Fountain Valley, CA.     

The Orange County Groundwater Replenishment System began as a response to a water shortage in Orange County in 1965. At this time it was discovered that the water table had dropped so low that ocean water was seeping in and contaminating the groundwater. Since Orange County currently gets about 60 percent of its water from the ground, protecting this source is very important.  To protect the groundwater, the district began a project known as Water Factory 21.


San Diego Coastkeeper Environmental Law & Policy Clinic staff and interns drink water from Orange County’s Groundwater Replenishment System, which is similar in concept to the wastewater recycling pilot project in San Diego.

Today’s program is an expansion of the successes of Water Factory 21. Water is pumped over from the sewage treatment plant next door. Within 45 minutes it is perfectly clean water. The plant uses a three-step process to clean the water. First, the water is filtered using a microfiltration system that sucks the water through very fine filters. Then the water goes through reverse osmosis where water is forced through the molecular structure of the Reverse Osmosis membranes. After this stage the water is exposed to ultraviolet light and hydrogen peroxide to disinfect the water and destroy trace compounds that may have passed through the Reverse Osmosis membranes.

Half of the now pure water is pumped into the seawater barrier to keep the seawater from infiltrating the groundwater basin, and half is pumped up and naturally filters into the groundwater. The system produces almost 70 million gallons of filtered water each day keeping the groundwater pure and plentiful.

After touring the entire process, we were able to taste the water. It was great. It’s so pure, and has no mineral content, so it’s practically tasteless.