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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1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
$199
6 U
.S. G
NP
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Wat
er W
ithdr
awal
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m3/
yr)
California Water Withdrawals and Economic Output Trends
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$100,000
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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
0 50 100 150 200 250 300 350 400
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
Cos
t of
Con
serv
ed W
ater
($/
AF
)
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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ion
Cub
ic M
eter
s p
er Y
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