Water Banner


H2Overview is a series of reports by Equinox Center that provide balanced, easy-to-understand research on San Diego County’s water supply to better inform regional stakeholders and the public. Recognizing that water is likely to be the most critical resource challenge that the San Diego region will face during the coming two decades, H2Overview reports serve to provide an overview of current and potential sources of water, as well as in-depth policy analysis on seawater desalination and purified water recycling. The reports have focused on the benefits, costs and challenges associated with the development of these water supply sources with the intent of spurring informed public dialogue and influencing decision-making about the region’s future water portfolio.

Equinox Center's February 2015 Report Shows Water Use is Up, Despite the Drought


Data for the February 2015 San Diego County Water Use Trends report can be found here.


Past H2Overview Reports:

Water Budget Billing In San Diego: Is It Worth It? At A Glance Summary, August 2013

Water Budget Billing In San Diego: Is It Worth It?, July 2013

The Potential of Water Efficienty and Conservation At-A-Glance Summary, October 2012

The Potential of Water Efficiency and Conservation: Opportunities in Single Family Homes in San Diego, October 2012

Past research:

H2Overview: The Potential of Seawater Desalination as a Water Source in San Diego County, December 2010

H2Overview:The Potential of Purified Recycled Water At-A-Glance Summary, July 2010

H2Overview: Potential of Purified Reycled Water, July 2010

H2Overview: San Diego Water Sources: Assessing the Options At-A-Glance Summary, July 2010

H2Overview: San Diego Water Sources: Assessing the Options, July 2010

H2Overview: Equinox Center Water Pricing Primer, October 2009

H2Overview: California Comprehensive Water Bill Equinox At-A-Glance Summary, February 2009

H2Overview: Comprehensive Water Bill Equinox Expanded Summary, February 2009

San Diego is a city seemingly surrounded by water, with breathtaking vistas of our harbors and bays.  Ironically, San Diego's waterfront playground hides the fact that we are a semi-arid climate with an average rainfall of only 10 inches per year.

If we had to rely on our local resources alone, we could support our county’s 3 million residents at current use rates for only two and a half months.

Water is our most precious natural resource - the ultimate element of sustainability. In San Diego County, nearly 60% of our water supply is used by residences, with only 17% used by business, and 12% used by agriculture.



SD County Water Usage

Source: San Diego County Water Authority Annual Report, 2008

San Diego's Vulnerable Water Supply

San Diego imports more than 80% of our water through the San Diego County Water Authority (SDWCA), mostly from Northern California and the Colorado River.  Exacerbating years of drought, a federal court ruling requires California to reduce water consumption from the Colorado River to comply with previously agreed upon water allocations. Studies from the Scripps Institute of Oceanography and the US Geological Survey have projected that our single largest supplier of water, the Colorado River, may face more delivery shortfalls in the future.

Meanwhile, our second largest water source, the State Water Project, is also at risk due to reductions from efforts to protect endangered species in Northern California's Sacramento-San Joaquin Delta, and aging infrastructure.

Enhancing Local Supplies Will Lead to a More Secure Water Future

Local water gives us more control over our future water supplies. However, San Diego’s surface and groundwater resources are limited. Currently, only 20% of our water supply comes from local sources, including conserved water, recycled water, local reservoirs and underground aquifers.

Nearly 60% of our water goes toward residential use, yet less than 3% of that is used for drinking and cooking.

Landscaping is the largest residential water use, totalling 55% of consumption, followed by toilets, showers, clothes washing, and faucets.


SD County Residential Water Usage


San Diego County expects to add 650,000 more people by 2030, which will increase water demand, and a changing climate is projected to increase the water needed to maintain San Diego’s lush landscapes and create greater water management challenges.

The SDCWA has plans underway to diversify our water sources, including more use of desalinated and recycled water. However, SDCWA projects that by 2020 San Diego will still need to import nearly 60% of our water.


Water Supply 2020




Saving Water = Saving Energy

Water use is inextricably tied to energy consumption. Twenty percent of California's energy use is associated with moving, heating or treating water throughout the state. Thus, on a broad scale, the more water we conserve, the more energy we conserve.

As San Diego strives to secure more reliable local sources, the energy implications of each water source must also be taken into account, as they vary significantly.   Currently, desalination requires more energy than importing water from Northern California.

In recent years, San Diegans have consumed 180 gallons per day (GDP) per capita. In recent months, the positive public response to the drought resulted in a reduction in water use between 16% and 21% county-wide. The current county-wide average in 2010 was 148 GDP per capita. As impressive as that is, we have a ways to go to compete with Seattle (105 GPD) or Australia (55 GPD), in the long term.  

If we manage to conserve significant water resources over time, we could also see substantial per capita energy reductions.  In addition to the region-wide benefits of reducing water (and energy) consumption, reducing the use of heated water in the home for things like washing clothes, running the dishwasher or taking a hot shower, also saves consumers money on their electricity or natural gas bills.  Using water more efficiently also could postpone the need for large scale, expensive infrastructure projects. 

Equinox Center Priorities

Given the vulnerable nature of imported water, the potential effects of climate change, and the impact of an unreliable water source on our quality of life, Equinox Center believes we need to be more ambitious when it comes to conserving our resources today and developing more local water supplies.

Providing for regional water needs will require political will and public investment in long-range solutions.  Equinox Center is currently completing a comprehensive series of reports on San Diego's water supply, called the H2Overview, including:

  1. Conservation —Conservation and water efficiency measures,  including appropriate pricing incentives and water efficient technology, have been proven to reduce demand,  reduce water-related energy use, and are highly cost-effective.
  2. Purified Recycled water —Purified recycled water  is safe, has a relatively low environmental impact and requires moderate energy use.
  3. Seawater Desalination — Seawater desalination would be a reliable local water source, but is expensive and requires a great deal of energy. Its potential as a viable local water source will be examined in detail.

Equinox Center has published the first four reports of the H2Overview. Click here to download these publications free of charge.


San Diego County Water Authority Annual Report 2008
San Diego County Water Authority Fact Sheet