Inside the World's Largest Water Recycling System
Orange County's Groundwater Replenishment System turns sewage into drinking water for a million people — and quietly became the proof point for reuse nationwide.
By AGUACYCLE News Room
In Fountain Valley, California, water that was recently sewage is purified to a quality cleaner than most bottled water, then pumped underground to refill the aquifer that supplies much of Orange County.
A 15-year proof of concept
The Groundwater Replenishment System has operated for more than 15 years and, after a 2023 expansion, produces enough water for roughly a million residents. The purified water also forms a barrier along the coast that keeps seawater from intruding into the freshwater aquifer.
Why it matters everywhere else
GWRS is the project nearly every U.S. utility points to when making the case for potable reuse. It reframed recycled water from an emergency measure into a reliable, drought-proof cornerstone supply — clearing a path that cities from San Diego to El Paso are now following.
Keep reading
Mapping America's Worst Drinking-Water Violations
Oklahoma's water systems break the rules at the highest rate in the country, while Texas racks up the most violations by sheer volume. The gap between those two numbers is the whole story.
Read analysisThe AI Boom's Thirst: How Data Centers Strain Water Supplies
The water cost of artificial intelligence is not just the cooling towers you can see — it is the vast withdrawals behind the electricity that powers them, increasingly in the driest corners of the country.
Read analysisShrinking Colorado River Pushes St. George, Utah Toward Recycled Drinking Water
With the long-planned Lake Powell Pipeline effectively shelved, Washington County is building a facility to turn treated wastewater into a new drinking water supply.
Read analysis