An article on Cleanlink reports:

The sustainable and efficient use of resources continues to be an area of emphasis for companies’ environmental responsibility initiatives. Many organizations are striving to reduce their environmental impact, and in the process save money, by reducing their use of energy and natural resources—including water.
 
An area that companies tend to overlook when assessing their environmental impact is the restroom, which accounts for about 37 percent of water usage in the average office, according to the EPA.
 
Beyond fixing dripping faucets and installing low-flow toilets, companies should consider the hand hygiene products used in their offices or facilities, which can have a significant impact on the total water consumption.
 
Wall-mounted, non-aerosol foam hand wash systems are an alternative to traditional liquid soaps. In these systems, an integrated pump in the cartridge mixes a special formula liquid soap with air to increase its volume by 10 times and provide an instant lather for hand washing.
 
Using foam soap rather than a liquid soap results in considerable reduced water usage, according to independent research conducted in the UK in 2009.
 
Researchers asked 150 people to dirty their hands to a moderate level and then wash their hands — once with traditional liquid/lotion soap and once with foaming soap. Participants used their handwashing method of choice without specific instruction. Researchers measured the water flow rate for each faucet. They also rotated which product was tested first to avoid order effects, and all the participants used liquid/lotion or foam soaps on a day-to-day basis.
 
Within the controlled study, participants used an average of 1,758ml (0.464 gallons) of water with the faucet on for 21.8 seconds when testing the lotion soap. For foam soap, the amount of water used was reduced to 1,475ml (0.390 gallons) of water with the faucet on for 19.7 seconds — representing a 16 percent water savings.
 
Presuming people wash their hands three times a day at work, an office of 100 people currently using lotion soap would save approximately 20,000 liters, or about 5,283 gallons, of water per year simply by changing to foam soap.
 
Changing hand hygiene products to a foam soap and educating employees on the preferred hand-washing method could result in significant water reduction — making it an environmentally and fiscally responsible choice. –

See more at: http://www.cleanlink.com/news/article/STUDY-Foam-Soap-May-Aid-Water-Conservation-Efforts–17259#sthash.taw1KJoW.dpuf