Why Your Kitchen Drain Keeps Smelling

Food scraps are the biggest culprit behind a smelly kitchen sink drain. Even when rinsing plates, small bits of food can cling to the pipe walls or get caught in the U-bend. Over time, they rot and release a foul odour while contributing to a blocked kitchen drain.

Tips to Fix It:

• Pour boiling water down the drain to loosen residue.
• Add 1 cup of vinegar and 1 cup of baking soda to break down food build-up.
• Wait 10–15 minutes and rinse again with boiling water.
• Clean your sink strainer daily to prevent food from entering the drain.
• If odours persist, call a professional plumber Melbourne to check for a deeper blocked drain Melbourne.

When grease and fats are poured down the sink, they may appear to flow away easily, but they harden as they cool. This creates a sticky layer that traps food, bacteria, and grime, leading to odours and slow drainage.

Tips to Prevent It:

• Avoid pouring grease or oil down the sink at all times.
• Wipe pans and plates with a paper towel before washing.
• Collect used cooking oil in a jar or can and throw it away once solidified.
• Once a week, flush your kitchen sink drain with hot water to help melt and move small grease deposits.

The P-trap (or S-trap) under your sink holds a small amount of water that prevents sewer gases from escaping. If that water evaporates, those gases travel up through the kitchen sink drain, causing an unmistakable rotten smell. This often happens in sinks that aren’t used regularly.

Tips to Fix It:

• Run water through the sink for 30–60 seconds to refill the trap.
• Pour a cup of water down unused sinks once a week.
• If the smell remains, check for leaks or cracks in the trap pipe.
• Use your kitchen sink regularly to keep the trap from drying out.

A sticky bacterial layer called biofilm often builds up inside the kitchen sink drain. It forms from leftover food, soap residue, and grease, and is one of the most common causes of persistent bad smells.

Tips to Clean Kitchen Sink Drain Effectively:

• Pour 1 cup of baking soda followed by 1 cup of vinegar into the drain.
• Let the mixture fizz for 10–15 minutes to break down the biofilm.
• Flush with boiling water to rinse everything away.
• Repeat the process weekly to keep the drain clean and fresh.
• For strong or recurring odours, ask a plumber to perform a professional drain clean.

If cleaning doesn’t solve the smell, there might be a blocked drain Melbourne deeper in your plumbing. These hidden clogs often occur in the main line or where multiple pipes meet, trapping wastewater that begins to smell over time.

Signs of a Hidden Blockage:

• Water drains slowly or pools in the sink.
• Gurgling or bubbling sounds come from the drain.
• Bad smells return quickly after cleaning.

Tips to Handle It:

• Avoid chemical drain cleaners; they can damage your pipes.
• Try using a plunger to move surface-level clogs.
• Call a plumber for a CCTV drain inspection to locate and clear the blockage.

If you have a garbage disposal, leftover food can get trapped inside, decay, and release unpleasant odours. Even without a disposal, residue in the waste trap under the sink can create similar problems.

Tips to Keep It Clean:

• Run cold water and a few ice cubes through the disposal for 60 seconds.
• Add lemon peels or a spoon of baking soda for a natural deodoriser.
• Avoid grinding fibrous foods like celery, corn husks, or onion skins.
• Clean your waste trap every 3–6 months if you don’t have a disposal.

A smelly kitchen sink drain may sometimes be caused by poor ventilation rather than buildup. If your plumbing vent is blocked or damaged, sewer gases can be pushed back into your home, creating a sharp, unpleasant smell that no cleaning can fix.

Tips to Resolve It:

• Check that your plumbing vents (often on the roof) are clear of debris or nesting animals.
• Listen for gurgling noises when draining, they often signal vent issues.
• Call a licensed plumber to inspect vent pipes and seals for damage or misalignment.

If the smell keeps coming back, even after multiple cleanings, it may be a sign of a serious plumbing issue. Persistent smells often mean wastewater isn’t draining properly due to hidden leaks, corrosion, or faulty installations.

Possible Causes:

• Damaged or corroded pipes leaking wastewater.
• Incorrectly installed traps or venting systems.
• Blocked main drains or full septic systems.

What to Do:

• Avoid masking the smell, it needs fixing, not covering.
• Book a professional inspection to identify and repair the problem.

Once your kitchen sink drain is clean, maintaining it regularly will stop bad smells from coming back. These small habits make a big difference in keeping your plumbing fresh and functioning.

Tips for Ongoing Maintenance:

• Run hot water after every use to flush away debris.
• Use vinegar and baking soda once a week to deodorise.
• Avoid pouring grease, coffee grounds, or starchy foods down the drain.
• Clean your sink plug, strainer, and overflow openings regularly.
• Flush boiling water through the drain every few days.
• Book a professional drain clean once or twice a year.

Sometimes, no matter how many DIY methods you try, the odour remains. That’s when a plumber should step in to assess the problem professionally. Persistent smells usually indicate a deeper issue that simple cleaning can’t fix.

When to Call for Help:

• Constant foul smells from the kitchen sink drain.
• Water draining slowly or backing up.
• Gurgling noises from pipes or drains.
• Leaks or moisture under the sink.

A professional plumber can use hydro-jetting or CCTV drain inspection to identify and clear the source of the problem safely and efficiently.

A smelly kitchen sink drain isn’t just unpleasant, it’s often a warning sign that your plumbing needs attention. Regular cleaning, good habits, and timely professional maintenance can keep your kitchen sink drain free from odours and blockages.

If you’re in Melbourne and dealing with a persistent blocked drain, Flowsafe Plumbing can help. Our plumbers provide expert drain cleaning, repairs, and inspections to keep your kitchen clean, safe, and smelling fresh. Call us today at 0489 982 138 or book us online for a free quote and get your kitchen smelling fresh again!