Americans underestimate household water usage

A survey conducted by Indiana University researcher Shahzeen Attari has found that many Americans are confused about the best ways to conserve water around the home. Her results have been published in the journal Proceedings of the National Academy of Sciences.

The survey of 1020 people first asked respondents what actions they felt would be most effective to conserve water for themselves and other Americans. They then estimated water use in 17 household activities and finally ranked four food items (rice, coffee, sugar and cheese) according to the amount of water they believed was required to produce the item.

Experts say the best strategy for conserving water is to focus on efficiency improvements such as replacing toilets and retrofitting washing machines. However, nearly 43% of participants cited taking shorter showers as the best measure, while very few participants cited replacing toilets or flushing less, even though toilets use the most volume of water daily. Interestingly, some respondents listed curtailment actions for themselves but efficiency actions for other Americans.

“People may be focusing on curtailment or cutting back rather than efficiency improvements because of the up-front costs involved,” Attari suggested. “It is also surprising how few participants mentioned retrofitting their toilets.”

When estimating the water used in household activities, participants on average underestimated water use by a factor of two, with severe underestimates for activities that use a lot of water. The respondents furthermore ranked the four food items about the same according to water requirements for production, even though the actual water requirements varied greatly.

The survey found that people from certain demographics appeared to have better perception of water use, including those with high numeracy, older age and of the male sex. However, underestimation was still significant.

“Given that we will need to adapt to more uncertain fresh-water supplies, a problem that the state of California is currently grappling with, we need to find ways to correct misperceptions to help people adapt to temporary or long-term decreases in fresh-water supply,” Attari said.