Rethinking Urban Water Use: Efficiency, and Conservation as Solutions to Water Problems. A Californi

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Rethinking Urban Water Use Efficiency, and
Conservation as Solutions to Water Problems. A
California Case Study

• Dana Haasz, Pacific Institute
• Oakland, California
• January, 2002

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California An Overview

• 1995 () 2020 Change
• Population(m) 32.1 47.5 15.4
• Urban water use(maf) 8.8 (11) 12.0 (15) 3.2
• Ag water use 33.8 (43) 31.5 (39) -2.3
• Urban per capita (gpcd) 132-349 115-326
• One in every 8 people in the US live in CA
• Popn density ranges from 2-16,000/mi2
• Fifth largest economy in the world
• Avg annual precip ranges from 2-90 in
• Water is in the north, popn is in the south

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Policies

• 1980 CA plumbing standards
• 1994 National Energy Policy Act (toilets
  showerheads)
• 2000 National energy standards for washing
  machines
• 2002 CA passes water standards for washing
  machines, taking effect in 2007
• 1992 CA Urban Water Conservation Council is
  established. 14 voluntary BMPs are developed.

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The link between water use and economic growth
can be broken
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Californias Economic Productivity of Water
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The Demand-Side Management Project

• QUESTIONS
• I.What is current demand?
• II. What is the conservation potential?
• What is technically feasible?
• What is socially/politically feasible?
• III. How much does conserving water cost?
• IV. How much can be conserved cost-effectively?

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METHODS

• Analysis based on end-use
• Savings calculated for
• Toilets
• Showerheads
• Washing machines
• Dishwashers
• Leaks
• Landscape use
• Includes energy savings
• Economic analysis based on costs to consumer

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RESULTS

• Over 700 TAF captured since NEPA went into effect

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Indoor Residential Water Use California
No Efficiency Improvements
Current Use
Full Efficiency
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Residential Water Use Existing and Potential
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Water Used for Toilets in CaliforniaActual and
Potential Savings to Date
All Inefficient Toilets
Current Use
All Efficient Toilets
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Washing Machines

• High efficiency machines use about 40 less
  water about 5,250 gpy/machine (0.016 afy)
• Energy savings of almost 60 400-570
  kWh/machine/yr
• Almost 7000,000 new washers are sold in CA each
  year. 11.5 of those purchased in 2000 were HE.

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Water Savings from Washing Machines (California)
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Dishwashers

• Account for less than 2 of residential water
  use.
• HE models can cut use by about 40 817gpy
  (0.0025 afy)
• 30 energy savings 64kWh/yr

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Cost of Fixture Replacement
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Cost of Conserved Water and Energy
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Fixture Rebates

• Clothes Washers
• 300 rebate for 138,000 households 668/f and
  0.22/kWh (0.63/therm) CUWCC
• 520 rebate saved water costs 650/af, energy
  0.031/kWh
• Dishwashers
• 460 rebate yields water savings at a cost of
  650/af

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Use of Reclaimed Water in California
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Outdoor Water Use

• Landscape use accounts for up to 70 of total
  residential use in some parts of the state.
• In an average year, about 25 of CAs urban water
  supplies are used outdoors.
• Lack of data is biggest impediment to
  conservation planning.
• Our estimates for statewide outdoor use ranged
  from 0.85 MAF to 1.6 MAF per year for 1990.
• 2020 projections ranged from 1.3 to 2.5 MAFY.

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Outdoor Water Use Methods

• Efficiency improvements were categorized as
• Management (eg. Scheduling, thatching, aerating,
  etc)
• Hardware (precision irrigation, moisture sensor,
  etc.)
• Design (turf reduction, choice of plants,
  perimeter design etc.)
• outreach practices (proper management, load
  shifting, etc.)
• Savings were estimated statewide.
• For economic evaluation we used representative
  lots based on agency data small/large,
  coastal/inland.
• Improvements based on reducing turf ET from 1.3
  to 0.8 and non-turf ET from 1.0 to 0.6.
• Devices used in economic analysis are moisture
  sensors, auto-rain shutoff, moisture probes and
  hose timers. Education and public outreach
  expenses are also included.

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Outdoor Costs Most Favorable
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Outdoor Costs Less favorable
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Specific Conclusions

• Saved water can be used to meet projected growth.
• Since NEPA enough water has been captured indoors
  to meet the needs of 6 million people.
• 1980-1998 population increased by 49 water
  demand increased by only 14.
• Aggressive conservation can further reduce indoor
  demand 30 by 2020, even as the population almost
  doubles.
• Under natural replacement all devices are cost
  effective, only dishwashers are not under
  accelerated replacement.
• Landscape water use has tremendous untapped
  potential, more data are required.

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Water Use Some Conceptual Challenges

• The measure of how much water we withdraw for a
  task does not tell us how much water is actually
  delivered to the user.
• Every municipal water agency in the world reports
  unaccounted for water (7 to 50).

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• The amount of water used to provide goods and
  services tells nothing about how much water is
  actually required to produce those things.
• We know how much water is used to flush a toilet
  or produce a computer chip or grow cotton in
  California, but very little research has been
  done to determine the minimum amount of water
  needed to do these things. The amount of water
  required to do a particular task or provide a
  particular service tells us nothing about whether
  the thing we did was worth doing.
• Society has yet to seriously consider whether
  using water to dispose of human wastes is
  appropriate, or whether a computer chip can be
  made without water, or whether it makes sense to
  grow cotton in California at all.

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Conclusion -1Failing to improve efficiency means

• Wasted water
• Wasted energy
• Increased scarcity
• Incorrect perception of actual demand or need for
  water
• Unneeded expenditures for new supply
• Continued conflict over ecosystem water needs

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Conclusion -2A New Approach is Needed

• Inexorable exponential growth in demand is not
  inevitable.
• Substantial improvements in the productivity of
  water use are possible economically and quickly.
• Capturing these improvements requires new tools,
  new knowledge, and new skills.