For this cross-sectional study, we used data from Porter Novelli Public Services and the ENGINE Insights’ PN View 360+ survey (https://styles.porternovelli.com), delivered August 16–18, 2021 (Appendix). Porter Novelli used quota sampling and statistical weighting to make the panel representative of the US population by sex, age, region, race/ethnicity, and education. All analyses were performed using SAS software version 9.4 (SAS Institute Inc., https://www.sas.com), and p<0.05 indicated significance. Survey procedures were used to assess the proportions of response variables by demographics. χ² tests were conducted to test the association of each response variable with each demographic variable. Post hoc Wald F tests from contrast statements and the SurveyReg procedure SAS were used to compare subgroups for demographic variables with >2 levels.

The survey defined tap water as water from faucets and asked participants if they agreed or disagreed with a series of statements (Table 1). One-third (33%, 95% CI 30%‒36%) of respondents incorrectly answered that tap water does not have bacteria or living things present. Men, African American or Black persons, and urban residents were more likely to answer incorrectly. More than half (62%, 95% CI 59%‒66%) of participants said that tap water could be used for rinsing sinuses, 50% (95% CI 47%‒54%) for rinsing contact lenses, and 42% (95% CI 38%‒45%) for respiratory devices. Men and urban residents were more likely to choose >1 of these incorrect answers.

Respondents were asked how they used their household tap water (Table 2). Most persons reported using tap water for drinking, cooking, bathing, and handwashing. Approximately one quarter (24%, 95% CI 21%‒27%) of persons reported filling humidifiers or CPAP machines with tap water, 13% (95% CI 11%‒15%) reported using tap water for nasal rinsing, and 9% (95% CI 7%‒11%) reported using tap water for rinsing contact lenses.

The results of this survey highlight opportunities to reinforce messaging regarding appropriate uses of tap water and recommendations for using water in medical devices at home. Although most persons understand what sterile water is and acknowledge that tap water is not sterile, a large proportion of persons responded that tap water can be used for nasal rinsing devices, contact lens rinsing, and filling respiratory devices. These findings represent an opportunity for public health practitioners and water utilities to continue communicating the value of US tap water and its appropriate use.

Although waterborne opportunistic infections can occur through multiple routes and can depend on a person’s health status, most NTM and Legionella infections are acquired through inhalation (9). In this study, 24% of respondents reported filling respiratory devices with tap water, consistent with a recent study in which 20% of respondents reported filling respiratory devices with tap water (8). Studies have demonstrated measurable concentrations of NTM (9), concentrated minerals (10), and other contaminants in aerosols from humidifiers (11). Water quality affects the quality of aerosolized air emitted from humidifiers, CPAP machines, and vaporizers, underlying the need for sterilized or distilled water to be used in those devices. Healthcare providers and pharmacists are uniquely positioned to share additional recommendations on appropriate waters (i.e., sterile, distilled, or boiled and cooled) for respiratory devices when they are sold or prescribed. Persons should be informed that they can reduce their exposure to waterborne pathogens by using distilled water or water that has been appropriately boiled and cooled and by regularly cleaning and disinfecting all respiratory devices that use water.

Water can be sterilized at home for safe home medical use for respiratory devices and neti pots (containers designed to rinse debris or mucus from the nasal cavity). Ordemann et al. tested water treatment options of UV light treatment, granular activated carbon filtration, and boiling to eliminate Staphylococcus aureus, Pseudomonas aeruginosa, Moraxella catarrhalis, Acinetobacter baumannii, Klebsiella pneumoniae, Legionella pneumophila, and N. fowleri. They reported that sterilization could be achieved by boiling water for 5 minutes then cooling, or by UV treatment (e.g., SteriPEN, https://www.katadyngroup.com) for 45 seconds or following the manufacturer’s instructions (12). The Centers for Disease Control and Prevention also has recommendations for preparing safer water for nasal rinsing, which includes boiling for 1 minute (3 minutes at elevations >6,500 feet) and cooling (13). Focused public health messaging and communications from health departments, pharmacists, and healthcare providers should increase awareness of how best to achieve sterile water at home for those who need it, reducing the number of biofilm-associated waterborne pathogens persons are exposed to when performing home medical activities.

Biofilm-associated waterborne pathogens make up a substantial portion of waterborne disease-related illnesses and deaths in the United States. Our results indicate demographic groups to which future public health and provider efforts should be directed to promote appropriate household tap water management practices when using home medical devices that aerosolize water or irrigate the eyes and nose. Public health messaging and healthcare provider guidance that incorporates risk factors for these device users and aligns with recommendations of the Centers for Disease Control and Prevention (2) are effective risk communication strategies that can influence population behavior change.