There is a decent guide by the FDA here: https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm316375.htm https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm316

There is a decent guide by the FDA here: https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm316375.htm https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm316375.h... You might have heard about certain amoebas being a risk of dipping ones head underwater in warmer bodies of fresh water: https://en.wikipedia.org/wiki/Naegleria_fowleri https://en.wikipedia.org/wiki/Naegleria_fowleri You probably won't find Naegleria fowleri in your common tap but there are a host of other protozoans and bacteria that can be dangerous to your health. Contrary to common belief, they probably won't kill you right away - and may not even cause an infection. But you are taking a risk and taxing your body's immune system and that particular area's sensitivity and inflammatory response. It's really not worth the risk considering the price of generic, sanitized, saline bottles that are less than a few dollars a gallon. The risk is small but it could end you due to the area we are discussing: https://en.wikipedia.org/wiki/Danger_triangle_of_the_face https://en.wikipedia.org/wiki/Danger_triangle_of_the_face I used aerosol saline sprays after I had deviated septum correction surgery. They are pressurized so there's no risk of internal contents becoming contaminated. This alone is worth the peace of mind. Plus the pressure helps in a way a normal neti pot or drip system cannot. I used large Neilmed bottles from Walmart but I did a quick search for you and found a 3-pack of Arm n Hammer saline aerosol for $12 which seems to be a solid price: https://amzn.to/2RMiseS https://amzn.to/2RMiseS Hope this helps. Good luck with your health, take care of yourself!