You should never pour hot water down your kitchen sink for the following reasons, both for plumbing engineering and long-term safety:
🔧 1. It Can Damage the Pipes (especially PVC)
- Boiling water (100°C or 212°F) can warp, soften, or crack plastic pipes like PVC or PEX.
- Pipe joints sealed with adhesive or rubber rings can loosen or degrade over time.
- Repeated exposure can lead to leaks, hidden water damage, and costly repairs.
🧈 2. Melts Grease Temporarily – Then Causes Worse Clogs
- Hot water temporarily melts grease and fat stuck inside pipes.
- But as the water travels farther down, it cools, causing the grease to solidify again, sticking to the inner walls.
- Over time, it forms thick, waxy clogs mixed with food debris, leading to serious blockages.
🔥 3. Disrupts the Drain Trap (P-Trap/U-Trap)
- The trap under your sink holds water to block sewer gases from coming up.
- Boiling water can cause that water to evaporate, letting bad odors rise into your kitchen.
- It may also crack the trap if it’s made of plastic.
🧯 4. Risk of Splatter or Injury
- Pouring boiling water into a cold metal sink or near food scraps may cause sudden steam or splashes.
- This can result in burns to your hands or face.
- In enclosed spaces, the steam can also feel suffocating if inhaled suddenly.
✅ Safe Alternatives:
- Let hot water cool before pouring it down the drain.
- To clean your drain naturally: use a mix of warm water + dish soap + baking soda + vinegar.
- For greasy pans: wipe off grease with paper towels and discard in the trash before washing.