Many people routinely pour boiling water down the sink after cooking, assuming it helps flush out grease and clean their pipes. However, this common habit can actually harm your plumbing. Most modern residential plumbing systems use PVC pipes, which are durable but not designed for extreme heat. Pouring boiling water—especially at temperatures around 200°F—can weaken these pipes over time, especially at the joints, shortening their lifespan significantly and increasing the risk of leaks and expensive repairs.

In addition to weakening pipes, boiling water can cause warping and cracking, especially in plastic systems. These issues often go unnoticed until they lead to major damage under cabinets or inside walls. Many people believe that boiling water helps dissolve grease, but this is misleading. While it may temporarily melt the grease, it doesn’t eliminate it—it simply pushes it further into the plumbing, where it eventually hardens again, creating stubborn clogs and drainage issues.

To avoid these problems, it’s important to adopt safer kitchen habits. Always wipe grease off cookware with a paper towel before washing it. This small step reduces how much grease goes into your pipes. You should also use drain cleaners occasionally—but choose ones that are gentle on PVC and designed to break down grease. These can help maintain a clean, odor-free sink without causing additional damage.

Those with garbage disposals should be especially cautious. Grease can stick to the disposal’s blades and walls, reducing performance and contributing to future clogs. Regardless of whether you have a disposal, it’s best to keep grease and boiling water out of your plumbing. Safer alternatives include letting hot water cool before disposing of it, reusing vegetable water for plants, or pouring it out slowly while running cold water to minimize thermal shock.

Ultimately, avoiding the habit of pouring boiling water down the sink is a small but powerful step in home care. Preventive actions like these save money and prevent stress. Taking the time to protect your pipes is not just about maintenance—it’s about peace of mind and preserving the comfort of your home for years to come.