Regarding potential bacterial risks associated with irrigation devices, we are aware of two issues that receive public attention from time to time:
1. The extremely rare presence of a dangerous amoeba, Naegleria fowleri, in the water used to create the irrigant. To avoid exposure, the US FDA advises using filtered, distilled, or previously boiled water for nasal irrigation, and the US CDC provides detailed information about boiling, filtering, and disinfecting water for nasal irrigation at www.cdc.gov.
2. The buildup of bacteria and viruses in nasal irrigation devices caused by the failure to properly clean the device after use. The underlying problem is that viruses and bacteria from your nose may be transferred to the device, under the right circumstances of temperature and humidity, the germs may colonize and then be reintroduced into the nose upon subsequent use. If you use the device daily and rinse it thoroughly before and after use, the risk is quite small. If the device is properly cleaned after use, the risk can be eliminated completely.