Hills with dried grass, dead trees and evaporating lake

Water and Drought Response

When drought conditions intensify, as they have in recent years in California, the ripple effect can be felt throughout our state. Given limited water supplies, we work to conserve water at PG&E facilities and in our operations, and to help our customers do the same, particularly in the agricultural sector. With the increased fire risk, we are also assisting the state and local communities in their efforts to prevent and protect against wildfires.

Our Approach

PG&E’s response to the state’s historic drought conditions is governed by an internal Drought Task Force, which works to identify and address impacts on PG&E’s operations, on our customers and in our communities. The strong link between energy and water usage means that there is much we can do.

Water is essential to operating our infrastructure—including our vast network of hydroelectric generating stations—just as it is essential to our customers in their daily lives. At the same time, about 19 percent of California’s electricity usage goes toward moving, treating, disposing of, heating and consuming water. This connection, also known as the “water-energy nexus,” places PG&E in a unique position to help our state and our customers.

PG&E is working proactively to respond to the drought in a number of ways:

  • Strategically managing our power generation facilities
  • Reducing water consumption at PG&E offices and service yards
  • Coordinating with key agencies to prevent and respond to wildfires
  • Outreach and guidance to customers, particularly those in the agricultural community, on how to reduce water usage

PG&E also reports its water data and strategies to the Carbon Disclosure Project, an international not-for-profit organization that requests information on behalf of institutional investors.

Water Use at Diablo Canyon

PG&E does not use freshwater for cooling at any of our power plants. At the Diablo Canyon Power Plant, we use saltwater from the Pacific Ocean for once-through cooling. The 2,240 MW nuclear power plant has a maximum discharge of 2.5 billion gallons per day, set by the facility’s Clean Water Act permit. PG&E closely monitors the marine environment at the plant by conducting regular studies and sampling, also required under the plant’s Clean Water Act permit.

In May 2014, EPA issued federal regulations under Section 316(b) of the Clean Water Act to minimize adverse environmental impacts from facilities that use once-through cooling. These regulations allow Diablo Canyon to continue to be regulated under California’s once-through cooling policy adopted in 2010, which is considered to be at least as stringent as the new federal regulations. At the state level, the California Water Board has adopted a policy on once-through cooling that generally requires the installation of cooling towers or other significant measures to reduce the impact on marine life from existing power generation facilities in California by at least 85 percent.

Diablo Canyon must comply with state policy by December 31, 2024. However, nuclear facilities may be granted an alternative to the compliance requirements if they meet certain cost and technical feasibility criteria. An alternative technologies assessment was completed in 2014 by Bechtel, with oversight by the nuclear review committee established by the State Water Resources Control Board. Given PG&E’s announcement of a joint proposal indicating that, pending CPUC approval, we would not seek to relicense Diablo Canyon at the end of our existing nuclear licenses, we will comply with the state’s policy without approval of alternative compliance requirements and pay an annual interim mitigation fee until the units cease operation.

In addition, PG&E uses an on-site desalination plant to generate the majority of freshwater for Diablo Canyon to support the internal operations of the facility.

Dry Cooled Conventional Sources

PG&E relies on air for cooling at its three natural gas power plants:

  • Humboldt Bay Generating Station is cooled with air radiators using a closed-loop liquid coolant and requires minimal water use.
  • Gateway Generating Station employs an air-cooled condenser, which uses approximately 97 percent less water and discharges 98 percent less wastewater than a traditional once-through cooled plant.
  • Colusa Generating Station also uses dry cooling and a zero liquid discharge system that recycles wastewater.

PG&E uses some freshwater for internal operations at the plants, but these are largely closed-loop systems that minimize the amount of water consumed.

Hydroelectric Generation

PG&E earns U.S. Green Building Award

PG&E was presented with the U.S. Green Building Award for the innovative water reuse system at our San Francisco Service Center Garage Building. The site achieved LEED Platinum after a remodel and seismic retrofit. As part of the remodel, we created a system to capture groundwater from an aquifer that runs under the building and use it for the building’s cooling system.

PG&E owns and operates the nation’s largest investor-owned hydroelectric system. Our hydroelectric power plants are largely non-consumptive, meaning that after water passes through turbines to produce electricity, it is returned to the river.

PG&E also uses water for energy storage to help balance daily variations in electric demand at the 1,212 MW Helms Pumped Storage Project. Located more than 1,000 feet inside the Sierra Nevada mountains, the non-consumptive Helms facility alternately dispatches water from an upper reservoir to a lower reservoir to produce electricity when demand is high, pumping it back uphill when demand is low.

Drought Working Group conserves water for beneficial uses

PG&E operates the Potter Valley Hydroelectric Project under a FERC license that requires minimum flows downstream from Lake Pillsbury, a storage reservoir, to protect Chinook salmon and steelhead populations in the Eel River watershed and for agricultural and domestic water use in the Russian River watershed. However, as our state’s drought persisted, Lake Pillsbury became perilously dry, threatening our ability to provide water for these important uses.

In response, PG&E created the Lake Pillsbury Drought Working Group, comprised of stakeholders in both the Eel River and Russian River watersheds, which collaborated to conserve water in Lake Pillsbury and ensure a water supply for both watersheds. Without the working group, storage levels in Lake Pillsbury would have dropped below critical levels and led to water curtailment.

Water Conservation in Our Facilities

PG&E’s offices and service centers rely on water for restrooms, kitchens, mechanical system cooling, vehicle washing and landscape irrigation. As the drought in California continued in 2015, PG&E stayed committed to conserving water at our facilities. Our efforts proved positive, with water use decreasing 7.8 percent compared to the prior year, exceeding our target of 4.5 percent. This was in addition to the 30 percent reduction we achieved over the previous five years.

We accomplished these reductions by finding and repairing leaks and replacing facility landscapes with drought-resistant designs, plants and materials. Outside 60 of our facilities, browning lawns displayed signs supporting the state’s Save Our Water drought message.

Lake with mountains in background.

Promoting drought awareness

We posted “Severe drought warning” signage at 200 buildings as well as at PG&E’s campgrounds located near our hydroelectric facilities.

Helping Customers Reduce Water Use

Save Our Water logo

PG&E partners on Save Our Water campaign

PG&E placed a “Save Our Water” message on bills and envelopes sent to 4 million customers. Our 1.7 million e-bill customers received the drought message in e-bill inserts.

PG&E offers customers a wide range of options to help them reduce their water use. Our water-saving solutions for residential customers include energy efficiency rebates for high-efficiency appliances, such as clothes washers and shower heads, and free wood chips for landscape mulching, which reduces evaporation. We also offer incentives to agricultural customers who convert from sprinkler systems to water-efficient drip irrigation, as well as programs for energy efficient pumping systems and more.

Altogether, customers who participated in PG&E’s programs reduced water usage by about 1.2 billion gallons in 2015, based on an analysis of our most common energy efficiency measures that deliver water savings. This was down from the 1.8 billion gallons of water saved in 2014, with the decrease primarily related to our program to help customers convert their sprinkler systems to drip irrigation alternatives. The sprinkler-to-drip conversion program is still available for field crops but was sunset in 2015 for tree-grown crops and vineyards, which substantially reduced the water savings recorded.

2015 Milestones

As the drought persists, PG&E continues to partner to conserve water and protect the watersheds where we operate. Our achievements in 2015 included:

  • Conserved water at PG&E facilities. We reduced water use by 7.8 percent compared to the prior year, which exceeded our 4.5 percent target. This was in addition to the 30 percent reduction we achieved over the previous five years.
  • Engaged our employees. PG&E led a grassroots Water Wise Pledge Campaign that encouraged employees to make a pledge to reduce their water usage at work and at home. Twenty percent of our workforce pledged to take actions such as taking shorter showers, checking for leaks and installing water-saving aerators.
  • Strategically managed our hydroelectric facilities. Working with state agencies and other stakeholders, we found ways to save water in our reservoirs so we could generate power during the summer peak periods. Conserving water early in the season also helps ensure adequate water supplies for communities, supports recreation and benefits the many species that depend on water.
  • Took new steps to prevent and mitigate wildfires. In addition to our routine vegetation management program, through which we inspect all of our overhead electric lines, PG&E provided $2 million in funding to local Fire Safe Councils for projects including creating emergency access roads and fire breaks, clearing fire fuel and helping residents create defensible space. PG&E also provided funding for daily aerial fire patrols along four routes to assist state and local fire agencies with early detection and response to stop fires from spreading. We conducted supplementary patrols of our power lines in high fire danger areas—nearly 54,000 miles of power lines—and removed 124,000 hazardous trees that have been killed by a combination of the drought and bark beetle.
  • Expanded agricultural energy efficiency programs and incentives. We continue to develop rebates and incentives on water and energy-saving appliances and equipment for our agricultural customers, including pump efficiency, variable frequency drives and energy efficiency financing. We are developing new approaches for managing irrigation and using audits to recommend energy and water conservation for food processing facilities. We are also helping customers replace sprinklers for field crops with more water efficient drip systems.

Measuring Progress

Water Use Statistics
2013 2014 2015
Water Withdrawal (Saltwater and Freshwater) (thousand gallons)
Water Withdrawal (Saltwater)
Diablo Canyon Power Plant Footnote 1 845,930,015 852,781,935 861,064,313
Once-Through Cooling 845,609,000 852,463,000 860,732,000
Seawater Withdrawal for Reverse Osmosis 321,015 318,935 332,313
Domestic and Process Water (Freshwater)
Diablo Canyon Power Plant Footnote 2 21,400 17,930 8,150
Humboldt Bay Generating Station Footnote 1 193 168 208
Gateway Generating Station Footnote 1 14,893 20,726 21,320
Colusa Generating Station Footnote 1 32,321 18,877 25,473
Facilities (Freshwater)
Offices and Service Yards Footnote 3 127,208 106,708 106,142
Permitted Water Systems Footnote 4 66,912 63,231 110,784
Hydrostatic Testing (Freshwater)
Water Withdrawal 6,166 5,974 5,537
Water Discharged (Saltwater and Freshwater) (thousand gallons)
Water Discharge (Saltwater) Footnote 5
Diablo Canyon Power Plant 845,798,691 852,651,462 860,928,367
Domestic and Process Water (Freshwater)
Diablo Canyon Power Plant (Permitted Discharge) 141,469 140,223 140,405
Humboldt Bay Generating Station (Sanitary Sewer) 73 80 114
Gateway Generating Station (Sanitary Sewer) 8,603 10,395 10,153
Colusa Generating Station Footnote 6 0 0 0
Hydrostatic Testing (Freshwater)
Total Discharge Footnote 7 2,132 4,120 2,798
  • 1. Net operating capacity on December 31, 2015: Diablo Canyon: 2,240 MW; Humboldt Bay Generating Station: 163 MW; Gateway Generating Station: 580 MW; Colusa Generating Station: 657 MW. Return to table
  • 2. Freshwater sources are well water for backup and emergency purposes. Return to table
  • 3. This figure represents the water supplied to offices and service yards managed by the Utility’s Corporate Real Estate Strategy and Services department for the 12-month period from October to September. The data includes between 125 and 135 sites between 2013 and 2015. Return to table
  • 4. PG&E monitors water usage at permitted, public water systems owned and operated by PG&E. These systems are metered in accordance with state regulations. Return to table
  • 5. These figures incorporate once-through cooling discharge (equivalent to withdrawal) plus estimated reverse osmosis system brine/backwash discharge. Return to table
  • 6. Colusa Generating Station uses a zero liquid discharge system. A septic system is used to manage sanitary waste. Return to table
  • 7. Of these totals, a portion of water was reused for other hydrostatic testing prior to being discharged, and more than half was recycled or reused for irrigation or dust control. Return to table

Looking Ahead

As drought conditions persist across California, PG&E will continue to promote water conservation with our customers and communities and at our facilities, setting a target reduction of 3.5 percent. We will step up our wildfire prevention efforts—pruning or removing approximately 1.1 million trees in 2016 to prevent them from growing or falling into power lines. We will also continue to strategically manage our hydroelectric operations and coordinate with business and government partners to reduce drought impacts in our state.

PG&E representative at Water Conservation Showcase speaking to attendee

PG&E hosts Water Conservation Showcase

PG&E held a Water Conservation Showcase at our Pacific Energy Center in San Francisco, bringing together hundreds of industry professionals to hear from experts and engage with new technologies. For PG&E, the event is an extension of the company’s focus on energy efficiency and sustainability, highlighting the direct connection between water and energy use.

Photo by James Green





Customers and Communities




GRI Index