national multiple family submetering and allocation billing program ...

of a property as a senior citizen/retirement community is closely associated with the presence of
a food service facility or restaurant. These factors can be said to covary. In subsequent
multivariate modeling, once the classification of a property as a senior citizen/retirement
community had been taken into consideration, the presence of food service facility or restaurant
was no longer statistically significant, indicating it no longer added unique information. This
analysis shows that senior citizen/retirement communities use about 12 kgal per unit per year less
than standard multi-family housing – a 23% reduction.
Similarly, dividing properties into categories of age based on year of construction (1994
and earlier or 1995 and later) proved to be the most powerful measure of non-efficient vs.
efficient water fixtures in the analysis. The federal Energy Policy Act (EPACT) of 1992
mandated the exclusive manufacture of ULF toilet, LF showerheads and LF faucet fixtures.
Hence by 1995 all construction in the United States included these efficient fixtures. Newer
properties equipped with efficient fixtures used 42.9 kgal per unit per year on average vs. 52.6
kgal per unit per year for older properties, a reduction of 9.7 kgal per unit per year (18%). It is
likely that this reduction is primarily due to the presence of high efficiency fixtures (toilet,
faucets, showerheads, and some high efficiency clothes washers) in the newer properties.
Reported replacement of toilets, faucets, showerheads, and clothes washers were less
significant predictors of water use than property age. This was perhaps due to inaccurate
reporting of fixture replacement rates on the manager survey. Discrepancies in the proportion of
fixtures estimated to be “low-flow” were found over 30% of the time for showerheads and toilets
and 50% of the time for faucets on the properties inspected on a site visit. However, the site visit
protocol had auditors testing actual flow from the fixtures while the manager survey asked
property owners or managers whether fixtures had been replaced since 1995. Although fixture
replacement and presence of efficient toilets, faucets, and clothes washers was statistically
significant in the preliminary ANOVA (Table 5.12), most of the difference in water use was
accounted for by the new (post-1994) properties. If these new properties were removed from the
analysis then the reported fixture replacement was no longer statistically significant. This clearly
points out some of the problems with self-reported fixture replacement information from survey
respondents, which was why the sponsoring utilities for this study insisted upon site visits to
verify some manager survey information.
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