Is Hot Water Required at Handwashing-Only Lavatories and Wash Stations?

John Parks, CPD, a Senior Mechanical Designer with ZRHD PC in Oklahoma City, recently posed a theoretical question on ASPE Connect: Should we, as an industry, look at whether hot water is really needed at handwashing-only locations? The 2018 International Plumbing Code (IPC) requires tempered water to be delivered from lavatories and group wash fixtures located in public toilet facilities provided for customers, patrons, and visitors, but is it really necessary? You could reduce energy usage and minimize costs for construction, maintenance, and utilities, all while maintaining the same level of health and sanitation.

John’s question sparked much debate on the ASPE Connect Open Forum, and here’s a taste of what our experts said. If you would like to read the full discussion or contribute your thoughts, visit ASPE Connect.

The Comfort Factor

Especially during winter in colder climates, the availability of tempered or hot water encourages handwashing, whereas cold (only) water does not. Warm water will encourage people to wash their hands simply because it is more comfortable than only cold, and particularly where the cold water temperature is below 70°F.

Fighting Germs

Providing hot or tempered water for handwashing is also an important part of sanitation. One expert personally witnessed people who didn’t wash after going to the toilet, and many times they said it was directly attributed to water temperature. It is a question of how long someone will keep their hands within the water stream. If the water is too cold, most people will not wash their hands for the suggested amount of time to cleanse them in combination with the soap solution.

Don’t Forget Our Furry Friends

What about buildings with pet spas? After taking hot water to such sinks, one expert received kickback from the architect, who said dogs didn’t need hot water in Florida. She replied that there also is a person washing that dog, so hot water is required.

Another expert recommends always providing hot water to animal bathing facilities, especially for mammals. Biologically, thermal shock affects them the same as it affects humans.

What About the Energy Factor?

With all of the above, those responsible for providing warm water for handwashing, particularly by code requirement, should do their utmost to deliver it in the best manner and performance possible.

Reducing non-circulating pipe lengths to save energy and water can contribute to higher levels of sanitation by minimizing the opportunity for stagnant water and the growth of biofilm and bacteria. Designers can also elect to provide more water heaters within buildings closer to the end-user points, eliminating excessively long runs for the hot water distribution systems. You also could consider point-of-use (POU) water heaters at lavatories to meet the demand of heating water from 55°F to 75°F.

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