Does anyone have scientific data on the water savings achieved by retrofitting faucets in schools from traditional to hands-free? 

We've researched Amy's book, LEED, Energy Star, BEAM, FEMP, and FEMP Watergy without success.

One study recalled by a colleague says there were no savings, and that, in fact, water use increased.  Some of us think that might be because students were more willing to wash hands (hygiene factor) under a hands-free faucet than a traditional one.  However, to calculate cost benefit analyses of savings, we need real data.

We would appreciate any help in getting this data in the next few weeks.  Thanks.

Liz Gardener,

Denver Water

Do sensor-activated commercial faucets save water?

In the past several years, the commercial side of faucets has been a topic of much conversation, if not research. Most water efficiency practitioners readily acknowledge that sensor-operated flush valves (for commercial toilet and urinal fixtures) save no water. In fact, they would quickly say that these devices waste water by flushing more frequently than necessary! But, what about faucets?

Millenium Dome Report on Water Efficiency-“Watercycle” (2002)

Thames Water’s “Watercycle” project at the Millennium Dome in London was one of the largest in-building recycling schemes in Europe, designed to supply up to 130,000 gallons per day (491.96 m3) of reclaimed water for WC and urinal flushing. It catered to over 6 million visitors in the year 2000. Overall, 55% of the water demand at the Dome was met by reclaimed water. The Dome was also the site of one of the most comprehensive studies ever carried out of water conservation in a public environment, evaluating a range of water efficient appliances and researching visitor perceptions of reclaimed water.

Of particular interest is Figure 6 in the report which shows washroom water use for handwashing and compares infrared sensor-operated faucets with “push top” (cycling) faucets and conventional swivel top faucets. It confirms that infrared sensors on the faucets create a waste of water when compared to conventional fixtures.

Hills, S. et. al. (2002) The Millenium Dome Watercycle Experiment - to Evaluate Water Efficiency

ASHRAE Field Study

Another study that compared manually operated faucets with sensor-activated faucets was published in 2002 by ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.). While not the main focus of the study, titled “Field Test of a Photovoltaic Water Heater”, Tables 3 and 4 provide data needed for the comparisons.

Fanney, A.H. (2002) Field Test of a Photovoltaic Water Heater

I cannot find any reputable study that found water savings from sensor faucets.  There might be improvements in hygiene with sensor faucets, but I do not think there is data to support water conservation claims.

I was involved in a school retrofit project for a foreign country where we retrofited with self-closing metered faucets. With only three weeks of data, we found about 18% reduction, but this is not a scientific study.  We had the metering set for 5 second flow per activation.  There was very low water pressure so the flow rate was about 7 ounces of water per activation.