Uses of Caustic Soda in Drain Cleaning

How to safely use NaOH to unclog pipes.
How to Safely Use Sodium Hydroxide (NaOH) for Drain Cleaning
Sodium hydroxide (NaOH), or caustic soda, is highly effective at breaking down
grease, hair, and organic matter in clogged pipes. However, it must be handled
with caution to avoid burns or pipe damage.
1. Safety Precautions
✅ Wear Protective Gear – Gloves, goggles, and long sleeves.
✅ Work in a Ventilated Area – NaOH can release fumes when mixed with water.
✅ Use a Plastic or Glass Container – Avoid aluminum or reactive metals.
❌ Never Mix with Other Cleaners – Especially acids (e.g., vinegar, bleach), as it
can create toxic gases.
2. Preparing the NaOH Solution
For a Mild Clog:
• 1–2 tablespoons of NaOH
• 500ml (2 cups) of cold water
For a Severe Clog:
• ½ cup (about 100g) of NaOH
• 1 liter (4 cups) of cold water
Mixing Steps:
1. 2. 3. Slowly add NaOH to the water (never the reverse) while stirring.
The solution will heat up as NaOH dissolves. Let it sit for a minute.
Carefully pour the solution into the drain.
3. Letting the Solution Work
• For light clogs: Let sit for 15–30 minutes.
• For tough clogs: Leave for 1–2 hours, or overnight if necessary.
4. Flushing the Drain
• Slowly pour boiling water (1-2 liters) down the drain to flush out the dissolved
material.
• If the clog remains, repeat the process or use a plunger before trying again.
5. When to Avoid NaOH for Drain Cleaning
❌ If your pipes are aluminum – NaOH corrodes aluminum.
❌ If there’s standing water in the sink – Use a plunger first to allow the solution to
reach the clog.
❌ For septic tanks – Excess NaOH can disrupt the bacteria that break down
waste.
Alternative Natural Method (If You Want a Gentler Option)
• Pour ½ cup baking soda into the drain.
• Add 1 cup of vinegar.
• Let sit for 30 minutes, then flush with hot water.