Tap water or "sterile" water for sinus irrigations: what are our patients using?

Nasal saline irrigations are a valuable, widely used adjunct for the management of chronic rhinosinusitis. Due to potential concerns regarding infection, patients are commonly recommended to use distilled, bottled, or boiled tap water when mixing these solutions. Anecdotally, patients frequently inform otolaryngologists that they use tap water for irrigation preparation. The purpose of this study was to assess patient adherence to preparation guidelines.

This study was a cross-sectional, anonymous survey of 100 consecutive patients using nasal saline irrigations for chronic rhinosinusitis on the instruction of the senior author. Patients received their instructions in a standardized manner including printed handouts and had been instructed to use distilled, bottled, or boiled tap water.

Patients almost uniformly reported improvement in their symptoms with the use of saline irrigations. No single water preparation was used by a majority of patients. However, tap water was used by 48% and the most common reason cited for using tap water was convenience. Of the patients using bottled, distilled, or boiled tap water, 65% described the process as "mildly" or "moderately" inconvenient. A large majority (70%) of patients report not adhering to cleaning instructions for their sinus rinse bottles.

Despite standardized instructions for the preparation of saline irrigation solutions, many patients use untreated tap water. The extremely rare, but typically fatal, risk of meningoencephalitis from Naegleria fowlerii makes this a potential health hazard.