Colorful California Landscape: A Water-Friendly Garden
Colorful California Landscape:  A Water-Friendly Garden


Water In The Home

People have low-flow showerheads, low-flush toilets and even low-flow faucets for kitchens, yet are not being conservative with the water usage for irrigating lawns and landscapes.  People are using more water in theirlandscapes than ever before and less in their homes.  According to Tom Girolamo in his book, Your Eco-friendly Yard: Sustainable Ideas to Save You Time, Money and the Earth (2009), the average person in their home uses about 40 gallons of water a day, down from 60 gallons prior to household water conservation measures.  Less than 1 gallon of water a day per person is consumed as drinking water.

Much of the water used in homes is simply to transport waste.  Our culture's fascination with flush toilets results in 2 gallons of perfectly clean water used to transport a few ounces of wate multiple times a day.  Many people find they need to flush water-saving toilets twice and then end up using more water than standard toilets.  Most pharmaceuticals from human waste have now reached detectable levels in rivers, oceans and groundwater.


The Orange County Water District (OCWD) manages and protects the large groundwater basin underlying north and central Orange County.  This 270-square-mile basin provides approximately 75% of the water needs for 2.4 million residents in north and central Orange County.  The region is expectd to grow by more than 300,000 people by 2035 (source: Cal State CDR).  Below is the OCWD service area map:

he Orange County Sanitation District (OCSD) operates the third largest wastewater agency west of the Mississippi River.  It collects, treats and disposes of the wastewater generated by the residents within a 470-square mile service area.  Each day, OCSD treats approximately 200 million gallons of wastwater - enough to fill Angel Stadium 3 times eady day.  About 80% comes from homes - sinks, toilets, showers, laundry and dishwashers.  The rest comes from businesses - retail stores, restaurants, manufactures, hotels, offices, and other industries.  The facilities include 580 miles of sewer pipes that snake throughout the county and 2 treatment plants - one in Fountain Valley and the other in Huntington Beach.

Groundwater Replishment

The Orange County Water District has the world's largest wastewater purification system for indirect potable water reuse.  The Groundwater Replenishment System (GWRS) takes highly treated wastewater that would have previously been discharged into the Pacific Ocean and purifies it to near-distilled-quality water using a 3-step advanced treatment process consisting of microfiltration, reverse osmosis and ultraviolet light with hydrogen peroxide.  The process meets or exceed all state and federal drinking water standards. The process only takes 45 minutes to produce high-quality water that exceeds all state and federal drinking water standards.

Operational since January 2008, this state-of-the-art water purification project can produce up to 70 million gallons a day (MGD; 265,000 cubic meters) of high-quality water daily.  In 2015, the project was expanded to produce 100 MGD.  This is enough water to meet the needs of nearly 600,000 residents in north and central Orange County, California.

This facility uses less than half the energy required to pump imported water from Northern Califonia and uses less than one-third the energy that it takes to desalinate ocean water.  It is one of the most celebrated civil engineering and water reuse projects in the world receiving more than 40 local, regional, national and international wards, including the 2008 Stockholm International Industry Water Award and the American Society of Civil Engineers 2009 Outstanding Civil Engineering Achievement Award!

Water Delivery

After the water is treated with the three step process at the GWRS, approximately half 35 million gallons of GWRS water per day are pumped into injection wells where it serves as a seawater instrusion barrier. Another 35 million gallons per day are pumped to recharge basins in Anaheim, where GWRS water filters through sand and gravel to replenish the deep aquifers of north and central Orange County's groundwater basin. Here is a video from the OCWD with animation showing this process.

Seawater Intrusion Barrier

The threat of sat water from the ocean contaminating Orange County's groundwater basin has been a concern for decades.  The groundwater basin is the county's primary potable water supply and provides storage for nearly 500,000 acre-feet of usable water.  As the region has continued to grow, water demands have risen.  Pumping more water out of the basin increases the possibility of salt water seeping into the basin.

The OCWD built Water Factory 21 (WF-21) in the mid-1970s to treat wastewater to inject into 23 wells along the coast, creating a seawater intrusion barrier.  As demands to pump more water out of the basin increased, the barrier required more purified water than WF-21 could produce, which had a daily production of 22.6 million gallons per day (14 million gallons of WF-21 water blended wtih 8.6 million gallons of deep well water).

With the completion of the GWRS, OCWD now produces enought water to form a highly protective barrier that safeguards Orange County's fresh water supply.  About half of the water produced by GWRS (35 million gallons) is injected into the seawater intrusion barrier every day.

Groundwater Recharge

The OCWD is responsible for managing a very large groundwater basin that provides approximatley 60% of the potable water supply for 2.4 million residents of north and central Orange County.

In 1936, OCWD began purchasing portions of the Santa Ana River channel to actively manage capture of the river water as a source of supply for the groundwater basin.  In 2010, OCWD owns approximately 1,000 acres contained within a six-mile section of the Santa Ana River from Imperial Highway to Ball Road in Anaheim, California.  There are more than 2 dozen recharge basins in this area that range in depth from 5 to 150 feet.

After water is purified through GWRS, about half of it is pumped in a 13-mile pipeline to 2 of OCWD's recharge basins, Kraemer and Miller, in Anaheim.  The GWRS water percolates through the sand and gravel in these basins and naturally filters into the county's groundwater basin.  This groundwater is pumped from over 400 wells operated by local water agencies, cities and other groundwater users.  The GWRS is an importan and effective way to replenish the groundwater basin.

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Stewardship requires the recognition that we are all caretakers of the environment and economy for the benefit of present and future generations. We must balance the impacts of today's decisions with the needs of future generations. - The Minnesota Round Table on Sustainable Development (1998)