Conservation Potential and California’s Urban Water Demand Gary Wolff, P.E., Ph.D. Principal Economist & Engineer April 2, 2004 Presentation.

Conservation Potential and California’s Urban Water Demand

Gary Wolff, P.E., Ph.D.

Principal Economist & Engineer

www.pacinst.org

April 2, 2004

Presentation at the

4th Annual North Bay Water Conference

Can We Grow The CA Economy Without More Water?

Yes. We’ve Done This For the Last 30 Years Can Continue If More Efficiency Is Possible Our Efficiency Potential Is STILL Large Our Efficiency Potential is Cost-Effective The Limiting Resource Is NOT WATER: It

is Our Ability to See the Big Picture and to Overcome Implementation Obstacles

Gleick 2001

The link between water use and economic growth can be broken

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.S. G

NP

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ithdr

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California Water Withdrawals and Economic Output Trends

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Gross State Product (Millions of 1992 $)

Water Withdrawals (MGD)

But Can We Continue To Grow Without Additional Physical Water?

No Comprehensive Statewide Estimate of the Potential for Urban Water Conservation Had Ever Been Done.

Such An Analysis – Done Right – Must Use An “End-Use” Approach.

Important Data Gaps Remain to be Filled

The Pacific Institute Report -- “Waste Not, Want Not: …”

Three-Year Process

Extensive Independent Reviews

Report Released in November 2003

Report and Appendices Available Online: www.pacinst.org/reports/urban_usage

Funded by DWR/CalFed; and the Hewlett, Environment Now, & MacArthur Foundations

California Urban Water Use – 2000 (6.9 million acre-feet per year)

Unaccounted for Water 10%

Industrial10%

Residential Indoor32%

Residential Outdoor

21%

Commercial27%

CII Sectors by Group

COMMERCIAL/ INSTITUTIONAL

Educational (K-12, Colleges, Special Education)

HotelsRestaurantsFood and Beverage StoresOther Retail StoresOffice BuildingsHospitalsGolf CoursesCoin LaundriesIndustrial Laundries

INDUSTRIAL

Food ProcessingDairyMeat ProcessingFruit and Vegetable Proc.BeveragesPetroleum RefiningHigh TechnologyPaper - Paperboard MillsTextilesFabricated Metals

How We Evaluated CII Potential

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Restaurants

Office Buildings

High Tech

TAF per Year

Restroom Cooling Landscaping Laundry Kitchen Process Other

Indoor Residential Water Use – 2000

(2.3 MAF/yr)End Use Acre-feet per year

Toilets 734,000

Showers 496,000

Faucets 423,000

Clothes Washers 330,000

Leaks 285,000

Dishwashers 28,000

Total 2,296,000

End-Use Analysis: Clothes Washers WU(t) = HH(t) x L/D x G/L = WU(t)

– WU (t) = Total Water Use at Time “t”

– HH (t) = Households at Time “t”

– L/D = Loads per HH per Day

– G/L = Gallons per Load

Compare WU(t) When G/L Changes, Holding Size of Loads Constant

Estimate of Conservation Potential Based on Comparing Average G/L Now With Average G/L of “Efficient” Machines

Some Economic Results – Residential Indoor Conservation

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ULFT Retroft Low-FlowShowerheads

EfficientDishwashers

EfficentClotheswashers

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t of

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ater

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AF

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Natural Replacement Accelerated Replacement

Haasz et al. 2002

Indoor Residential Conservation Potential Over Time

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1980 1985 1990 1995 2000 2005 2010 2015 2020

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ic M

eter

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ear

No Efficiency Improvements

Current Use

Cost-Effective Efficiency *

Total Urban CA Efficiency Potential

Sector Urban Water Use, 2000 (TAF/Yr)

Efficiency Potential

Cost-Effective Potential

Res-Indoor 2,300 893 893

Res-Outdoor 983 – 1,900 360 to 580 470

Comm/Inst. 1,850 714 658

Industrial 665 260 Incl. in C/I

Unaccounted

695 Not Eval. Not Eval.

Total 6,960 (+/- 10%) 2,337 2,020

Conclusions: Growth in Water Demand Is Not Inevitable Future Demand Need Not Grow Because

Additional Improvements in Water Use Efficiency Are Possible and Economical

But Implementing Change Requires:– Partnerships Across Traditional Boundaries

(e.g., Water/ Wastewater/ Stormwater/ Energy)– Capturing the “Other Benefits” We Identified– Better Balance of New (e.g. Customer Behavior)

and Old (e.g., Hydrologic) Uncertainties