national multiple family submetering and allocation billing program ...

Continuous Variables that Were Associated with Water Use
Statistically significant factors that influenced per unit indoor water use from the Pearson
Correlation analysis included:
! Average number of bedrooms per MF unit
! Average rent per bedroom
! Average number of people per unit
! Utility’s average commodity charge for water and wastewater 27
! Number of months of irrigation
! Percent of clothes washers replaced since 1995
Factors such as toilet replacement rates and faucet replacement rates that were close to
being statistically significant in both 2001 and 2002 were utilized in subsequent modeling, but
were never found to improve the overall fit of the model and hence were eventually excluded.
Continuous Variables that Were Not Associated with Water Use
The following list of factors were found not to have any statistically significant impact on
water use in this sample of multi-family properties.
! Percent of property that is irrigated
! Number of residential buildings on property
! Average rent per unit
! Number of units in property
! Acreage of property
! Reported water and wastewater rate (from the manager survey)
! Vacancy rate
! Percent of units with clothes washers
It is not surprising that factors related to outdoor use and irrigation (acreage and percent
irrigated) showed no statistical significance since indoor and outdoor use were explicitly
separated for this analysis as described in Chapter 3. Similarly, all water use was calculated on a
per unit basis hence the number of units in the property should not be an important factor.
Interestingly, factors that are often considered important to water use such as average rent and
vacancy rates were not statistically significant in this sample (although average rent per bedroom
was statistically significant).
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