Why Chemical Drain Cleaners Hurt Pipes

Why it matters

Most retail drain cleaners are strongly alkaline (lye) or acidic. They generate heat as they react with a clog. In older pipe, that heat and chemistry can soften plastic joints, attack old metal and crack porcelain. When they fail to clear the blockage, a sink full of caustic liquid sits waiting, and a plumber must work carefully around it.

Step by step

1. Try boiling-hot water carefully for soap and light grease in a metal drain, or very hot tap water for plastic.
2. Use a plunger with a good seal. For a double sink, block the other side first.
3. Pull hair from bathroom drains with an inexpensive plastic barbed strip.
4. Clean the trap under the sink by hand over a bucket.
5. Try enzyme treatments as maintenance, not as a fix for a total blockage.
6. Call for a cable if the clog is beyond the trap.

Common mistakes

• Mixing different drain products, which can cause dangerous reactions.
• Plunging after adding a chemical, which can splash it up.
• Using chemicals in a toilet, where they rarely reach the clog.
• Pouring openers into a fully blocked drain where they just sit.

When to call a plumber

Call if two attempts with a plunger fail, if several drains are slow together, or if a chemical has been used and the drain is still blocked. A mechanical cable or jetting clears the line without harm. See kitchen drain cleaning.