I have been washing out my sinuses since I was about 11 years of age. A wonderful Ear, Nose and Throat doctor in Princeton, NJ, who came highly recommended to us by my sister who at the time was the Director of the Speech and Hearing Division at the Princeton Medical Center, taught me how to do it. His technique was to use a small syringe, filled with warm salty water. Did I like it? NO! That warm blast of water up my nose was miserable. Did it work? YES! The amount of nasty looking mucous from my sinuses was proof positive it worked. Why did I need it? I was a constant ear infection kid. Tonsils and adenoids from repeated sore throat infections, were removed at age 2, and tubes in the ears (myringotomy) several times from age 7 and up. This led my parents to finding an ENT that understood that the prevention of the infection early was a clear path to reducing the number of times I had to be placed on antibiotics.
As an adult, I switched to a neti pot and LOVE it! But have to admit I have been a tap water user....not anymore! Distilled it shall be from this point forward. And from what I read, make sure those pots are cleaned out routinely as well. It was suggested that purchasing a new one every couple months is a good idea as well.
They are still not sure if the problem came from the water in the neti pot, or swimming in local ponds, but better to err on the side of caution. After all, no water treatment facility can remove every contaminant from our water. And well water is not as pure as many like to think it is. In fact if you have not done so recently, send away for a water test kit and do it yourself. Even if you have city water, a town well or well water, it is a good idea to check your water once every year or so. With the number of people using pesticides and fertilizers, rodent repellent products, weed killer and more on their shrubs, lawns, and flowers it all has to go somewhere. All this gets washed out by rain water and soaked into the ground water. Even if you are the green one in your neighborhood, using only the most organic of products on your lawn, many of your surrounding neighbors are not, so have it checked.