A recent study from Johns Hopkins Hospital looks at whether or not automatic faucets can really help prevent potentially dangerous microorganisms from spreading compared to traditional faucets. With automatic faucets a person can start and stop the flow of water without touching the faucet with soiled hands. This means that the surface of the faucet is less likely to be contaminated with bacteria that can spread to the next person who touches the faucet.
However, the doctors of Johns Hopkins Hostpital have found that automatic faucets contain complex mechanisms that harbor microbes like Legionella pneumophila. Water samples were taken from the hospital’s automatic faucets, and around 50 percent of them contained these harmful bacteria. In contrast, only about 15 percent of the samples from traditional manual faucets were found to harbor Legionella pneumophila. The automatic faucets overall had twice the bacterial load of the manual faucets.
This bacteria is responsible for legionellosis, a respiratory infection that people with underlying illnesses or compromised immune systems are prone to. For most people, Legionella pneumophila is not particularly dangerous. In Illinois there 25 to 50 cases of leginellosis every year and between 5 and 30 percent of these cases are fatal.
It’s not clear that this study has much application outside of hospital settings where there are people who are particularly vulnerable to certain infections. The researchers did not compare the water samples’ bacterial loads to those of the handles in manual faucets. The study does not really address this issue.