I have read you use tap water to irrigate NG tube, but have also read you should use sterile water. However, I took my ATI practice test and it reads this, "0.9% sodium chloride - rationale: 0.9% sodium chloride is an isotonic solution that would be least likely to cause electrolyte imbalance" sterile water and tap water, neither is not isotonic and can lead to electrolyte imbalance. I found this interesting and wondered what everyone else has learned, read, or is actually practicing in the real world of nursing.