Using a neti pot with tap water may be dangerous or deadly if the water is contaminated. Experts recommend distilled or boiled and cooled water.
Remember: Tap Water Is Not Sterile
Man dies of brain-eating amoeba possibly after rinsing sinuses with tap water : NPR
Neti pots provide sinus relief without much danger when used correctly - Grand Forks Herald
Ritual Nasal Rinsing & Ablution, Naegleria fowleri
Tap Water for Medical Uses at Home - Rhino Clear Sprint
How to Use a Neti Pot Safely
Tap water in neti pots cause fatal risk
Don't use a neti pot until you've read what can go wrong
Neti Pot Sinus Rinse Bottle with 100 Nasal Wash Salt Packets Nose Wash Cleaner Pressure Rinse Nasal Irrigation for Adult & Kid BPA Free 300 ML with Sticker Thermometer(Blue) : Health
Should You Use a Neti Pot or Another Type of Nasal Irrigation?
VERIFY: Can using tap water in a neti pot lead to a deadly infection?