“Vision, innovation & collaboration” - Expanding Orange County’s Groundwater Replenishment System

The Orange County Water District Groundwater Replenishment System has been a game-changer for the region's water management, recycling wastewater to produce clean, safe drinking water.

Now the final major expansion of the GWRS is complete, making it the world’s largest indirect potable reuse facility.

The world’s largest indirect potable reuse facility

Water scarcity has long been a major challenge for California, with frequent droughts and growing populations putting pressure on water supplies.

In Orange County, the Groundwater Replenishment System (GWRS) has been a game-changer for the region's water management, recycling wastewater to produce clean, safe drinking water. Now the final major expansion of the GWRS is complete, increasing the water treatment capacity from 455 m3/day to 591,000 m3/day.

The GWRS is the world’s largest indirect potable reuse facility. It is a joint project of the Orange County Water District (OCWD) and the Orange County Sanitation District (OC San) and uses a combination of microfiltration, reverse osmosis and UV disinfection to remove impurities from wastewater. 

“GWRS is an example of vision, innovation and collaboration”

Purified water is then pumped into natural underground aquifers, where it is stored and allowed to slowly percolate through the earth. By recycling all available wastewater, the GWRS reduces reliance on imported water sources and helps maintain a sustainable local water supply.

“The GWRS is a premier example of vision, innovation, and collaboration, all which are key components of the project’s successes over the years, further cementing our pioneering role in water reuse,” said OCWD Board President, Cathy Green. 

OCS San Board Chairman Chad P Wanke added: “I commend the partnership and dedication of both agencies in completing the final expansion of this facility.

“Reaching this major milestone of recycling 100 percent of our reclaimable wastewater flows enhances our efforts to protect public health and the environment by reusing this valuable resource.”

History of the GWRS project

The GWRS has been operational since 2008 and has already played a significant role in ensuring a reliable water supply for Orange County. However, with the region's population continuing to grow and water demand increasing, the expansion of the GWRS was therefore a vital development. 

The new facility adds a 50,000-square-foot building and new treatment processes to maximise the recycling of wastewater. The added capacity means that the GWRS now produces enough to serve around one million people. 

The completion of the GWRS expansion is a major achievement for Orange County and its water management efforts. As well as providing a reliable water source for residents, the GWRS also benefits businesses in the area. A secure water supply is essential for industries such as agriculture, manufacturing and technology, which rely on water for everything from irrigation to product processing.

A multi-million dollar project

The expansion project cost around $284 million and was funded by a variety of sources, including state and federal grants, loans and private investments. Many local agencies and water districts also worked together to ensure the project was completed on time and within budget.

The expansion of the Groundwater Replenishment System is a significant milestone in Orange County's water management efforts. By recycling wastewater to produce safe, clean drinking water, the GWRS is helping to ensure a reliable water supply for residents and businesses alike. 

Elsewhere, Namibia is moving ahead with its second direct potable reuse project, after German bank KfW agreed to provide finance.

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