The average single-family home in the East Bay Municipal Utility District used 135 gallons of water per person per day last year.

But it's hard to know just where that water went. Water meters are generally read every other month, and water districts don't typically have great software capabilities to give granular insight into their residential customers' water use.

Now WaterSmart Software, a small startup in San Francisco, is working with local water districts in California and other states to transform meter data into easy-to-understand home water reports that are mailed directly to homeowners or made accessible via the Web and mobile devices.

Watersmart offers subscibers a "WaterScore" in a monthly home water report.
Watersmart offers subscibers a "WaterScore" in a monthly home water report. ( WATERSMART )

WaterSmart now has 15 water district customers in four states, and several more pending. Clients include the cities of Palo Alto, Cotati and Sacramento, the Soquel Creek Water District, and the East Bay Municipal Utility District, or EBMUD. The San Jose Water Company is not currently a customer.

The company helps households compare their personal water use to that of neighborhood averages, a technique known as "behavioral water efficiency" that seems to be effective at driving conservation and savings. WaterSmart has been described as Oower, but for water; Opower is the software-as-a-service company for the electric utility industry that celebrated its $116 million IPO earlier this month.

California water utilities are being asked to reduce their per capita water use 20 percent by 2020, and many water districts are eager to think of new, creative ways to encourage consumers to conserve water.

"We know that people regularly underestimate how much water they use," said Andrea Pook of EBMUD. "And the water bill isn't a hugely effective way for people to understand their use. The home water reports allow us to really target information."

EBMUD used WaterSmart Software with 10,000 residential customers during a one-year pilot. Residential customers were provided personal water use reports that compared their water use to similar sized homes in the area and made recommendations on ways to save water.

EBMUD was hoping for a 2 percent increase in conservation, but the pilot drove a 5 percent reduction in residential water use and was so successful that EBMUD is now expanding it to 100,000 customers.

In Palo Alto, about 75 percent of the city's residential customers are currently receiving quarterly Home Water reports. Residents living in single-family homes can also log on to WaterSmart's WaterInsight portal through any Web browser and mobile device to view more detailed water use history. City of Palo Alto Utilities staff can access customer data, track water savings citywide, and run analytics in WaterSmart's Water Efficiency Dashboard.

"The residents of Palo Alto have led the nation in innovation for decades, and we are extremely proud to help them move toward a water efficient way of life with our own innovation," Peter Yolles, Founder and CEO of WaterSmart, said in a statement.

As customers receive printed home water reports, they can update their profile on WaterSmart's website so that all information, from how many bathrooms they have to how many people live in the house, is current. That information helps WaterSmart customize conservation recommendations and encourage consumers to "pledge" to make specific changes, like investing in a more efficient toilet, replacing a shower head or replacing a grass lawn with drought tolerant plants.

"As customers pledge to take specific conservation measures on the website, engagement levels go way up," said Jeff Lipton, WaterSmart Software's marketing director. "And as we convert customers to digital, costs go down, because the utility no longer has to mail reports."

The City of Palo Alto has seen a significant increase in the number of calls and emails about water use and conservation from customers since it began working with WaterSmart last fall.

"People have been telling us 'these reports are incredible, can you tell me more?'" said Catherine Elvert of the City of Palo Alto. "People are really drilling down into their water use."

Contact Dana Hull at 408-920-2706. Follow her at Twitter.com/danahull.