Hot tap water (120°F–130°F) is almost always sufficient to clean a drain. Boiling water is a weapon of last resort. While one pot likely won't destroy your pipes, doing this weekly will gradually degrade your plumbing system. Treat your drains gently, and they will last a lifetime.
Boiling water is generally safe if you have older, heavy-duty plumbing systems, specifically: boiling water down drain
Standard PVC pipes are usually rated for temperatures up to 140°F (60°C) . The Boiling Point: Water boils at 212°F (100°C) . Hot tap water (120°F–130°F) is almost always sufficient
If your drain is clogged with soap scum or animal fats, boiling water is a fantastic, chemical-free first strike. Treat your drains gently, and they will last a lifetime
Pouring boiling water down a drain is a common "quick fix" for clogs, but modern plumbing experts generally advise against it. While it may seem like a natural way to dissolve grease or soap scum, it can lead to severe structural damage depending on your home's pipe materials.
For deeper clogs, a manual snake can physically break through the obstruction without risking the integrity of the pipe walls. The Bottom Line