Yes. Pouring an ordinary household amount of plain white vinegar down a sewer-connected sink is generally safe and should not damage sound PVC or uPVC drainpipes. Run cold or lukewarm water briefly afterwards. Never use a stormwater drain or mix vinegar with bleach, chlorine products or drain cleaners.
Will vinegar damage PVC pipes?
Household white vinegar is dilute acetic acid. PVC chemical-resistance guidance, including Vinidex tables, indicates that sound PVC is resistant to dilute acetic acid at ambient temperatures.
This does not apply to concentrated acetic acid, unidentified liquids, damaged pipework or every pipe material. Read why boiling water can damage a drain rather than using it to flush vinegar or a blockage.
How to dispose of vinegar safely
Plain, uncontaminated old vinegar can be disposed of through a sewer-connected kitchen or laundry sink in an ordinary household quantity. Then run tap water briefly to dilute it and clear the trap. Vinegar and bicarbonate of soda are not a reliable way to unblock a drain.
- Avoid stormwater drains: Do not pour vinegar into gutters, street drains or outdoor stormwater grates. In Sydney, stormwater generally flows to waterways without sewage treatment.
- Check outdoor sinks: An outdoor sink is not necessarily connected to the wastewater system.
- Do not dispose of unknown mixtures: If the bottle is unlabelled, contaminated or contains other substances, do not pour it into any drain.
Never mix vinegar with bleach. Acid reacting with sodium hypochlorite bleach can release toxic chlorine gas. Do not add vinegar to a drain that may contain bleach, chlorine products or drain cleaner, and do not attempt to neutralise chemicals in the drain.
If mixing produces fumes, leave the area and move to fresh air. Call the Poisons Information Centre on 13 11 26 for advice, or 000 if anyone has breathing difficulty or collapses.
For concentrated acetic acid, bulk quantities or unidentified mixtures, keep the container closed and follow its label and current NSW EPA Household Chemical CleanOut or local council guidance.
If a sewer-connected sink is blocked or may contain unknown chemicals, add nothing further. Contact our licensed Sydney blocked sink plumbers and tell them exactly what entered the drain.