national multiple family submetering and allocation billing program ...

110
Average Annual Water Use Per Unit (kgal)
100
90
80
70
60
50
40
30
20
10
0
56.39 52.04 68.21 50.71 55.32 52.85
All Properties,
Pre-conversion
N=46
All Properties,
Post-conversion
N=46
Submetered,
Pre-conversion
N=6
Submetered,
Post-conversion
N=6
RUBS,
Pre-conversion
N=39
RUBS,
Post-conversion
N=39
Figure 5.18 Average annual water use per unit before and after conversion
Table 5.26 shows that among all 46 properties, annual water use per unit decreased 4.4
kgal after conversion compared to water use prior to conversion. However, this difference just
missed being statistically significant at the 0.05 level, as can be seen in Table 5.27 where the
results of a dependent t-test are shown. It was statistically significant at the 93% confidence
level.
Table 5.26 Estimated water use before and after conversion, all converted properties, N=46
Std.
Mean Deviation
Estimated Annual Water Use per Unit Prior to Conversion 56.39 23.75
Estimated Annual Water Use per Unit After Conversion 52.04 21.09
Change in Estimated Annual Water Use Before and After Conversion -4.35 15.90
Percent of Properties That Decreased Annual Water Use per Unit 56.52%
Percent of Properties That Did Not Change Annual Water Use per Unit 6.52%
Percent of Properties That Increased Annual Water Use per Unit 36.96%
173