Back in 1985, there were around 3.5 million people in the
LADWP service territory. Their water demand amounted to around 190 gallons
per person per day. The City's per capita use is less than many western
Cities (such as Denver, El Paso and Phoenix), but it is higher than percapita
use in Cities like Tucson and Goleta. As part of their 1985 Urban Water
Management Plan, the City projected that per capita demand would grow
to around 195 gallons per day in a future "without conservation".
When conservation efforts were factored into the forecast, per capita use
was reduced to 175 gallons per day. This initial estimate of "conservation
savings" is less than 10%.
In my opinion, the 10% figure is a lower bound on the potential for water
conservation. You should understand that the terms"water conservation"
and "water efficiency" are used interchanably. You have read in
Chapter 23 of Modeling the Environment, that efficiency programs
have proven extremely valuable for electric utilities. They also have important
value for water utilities. By encouraging their customers to invest in more
efficient equipment (i.e. low flow toilets), water utilities reduce the
requirements to turn to more and more expensive supplies of water. I believe
the potential for efficiency savings in the LADWP's service area is easily
double the 10% estimate prepared back in 1985.
To place the efficiency potential in perspective, imagine the savings if
the LADWP's demand were reduced by 20%. Total demand in the 1980s would
be reduced from 620 KAF/yr to under 500 KAF/yr. The saving would be 120
KAF/yr, more than the entire diversions from the Mono Basin. You can read
about the City's plans to tap this potential at the end of Chapter 4 in
Modeling the Environment.