2010-10-26_PWETC_AgendaPacket - Laserfiche WebLink

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Data Analysis An aggregate analysis of residential water usage was made to compare household usage before and after the new conservation-based rates was instituted. The focus was placed on summertime usage where household usage was highest and therefore most sensitive to any rate changes. Prior to the new rate structure, the average summertime household use was 23,000 gallons per quarter. After the new rate structure was put in place, average summertime household over the past two years dropped to 22,000 gallons per month - a 4% decrease. Using this simple comparison one might conclude that the conservation rates had an impact and resulted in lower usage. However, the amount of rainfall during these summertime periods increased from 2.3 inches per month in 2008 to an average of 3.9 inches per month in 2009-2010. Arguably, the added rainfall during the past two years played a significant role in the decline in household usage. A secondary analysis was conducted on a subset of the 400 highest residential water users in the City to determine whether those households that were most impacted by the new rate structure changed their consumption behavior. The analysis demonstrated that this subgroup exhibited the same usage patterns as those in the aggregate. Prior to the new rate structure, the average summertime household for this subgroup was 79,000 gallons per month. After the new rate structure was put in place, average summertime household over the past two years dropped to 75,000 gallons per month - a 6% decrease. Like the aggregate group, it is suggested that this subgroup's decline in usage was also influenced by the increased rainfall amounts and not due to the higher rates that accompanied the new rate structure. Clearly this group was not averse to going well beyond the 30,000 gallon mark despite the higher rates. Conclusion while the data is somewhat inconclusive, it is evident that the presence of the current conservation- based rate structure has not had a significant impact on residential water usage. It's conceivable that the water rates could be increased to reach a price point that would change consumer behavior. However, this could disproportionally affect those households that have already exhausted their means of reducing their consumption. It is suggested that there may be equally effective tools such as greater education and awareness or advocating for new societal norms that could achieve the same outcome as higher prices would. 2