Why Is Your Kitchen Sink Always Clogging? Find Out the Causes & Solutions

A kitchen sink that is constantly clogging can cause a great deal of frustration. You might clear the blockage and everything seems fine until it happens again a few days later. There could be a slow flow or some water sitting in the sink. Whilst this might seem like a simple issue caused by food matter and oil, it could be an underlying problem within your plumbing system.
Buildup of oil, food particles stuck in the drain, soap scum, broken pipes or an underlying blockage within the drain can all cause issues with your kitchen sink drain repair and replacement. To help you figure out what exactly is causing the problem, professional drainage cleaning and repair can be used.

7 Common Causes of a Kitchen Sink Clogging

Kitchen sinks are very busy places. With lots of washing up, vegetable rinsing and cleaning of oily cookware, there is a lot to go down the drain. Over time, some of this can build up along the piping. Here are 7 common causes:

1. Grease/Oil/Fat:

One of the most common causes of blockages in kitchen sinks is buildup of oil. When cooking with oily pans or pouring leftover oil down the sink, some of it will go down the drain. Liquid oil may pass through the pipes, it will begin to cool and stick to the inside. This will then create a sticky build up which causes food to get stuck. This can narrow the inside of the pipes. Hot water can help to melt some of the oil, but it will not clean it away. Once the water has gone cold, the oil can build up further down the pipe.

2. Food Matter Build Up:

Small food particles can cause a real issue with a clogged kitchen sink. Rice, Coffee grounds, Vegetable matter, pasta and other leftover food can all build up in your sink drain. Some foods can soak up water and expand. Others can get stuck in bends and narrowed areas. This can cause dense blockages when combined with oil. Using a sink strainer can help to stop most solid food from going into your plumbing.

3. Soap Scum & Mineral Buildup:

Whilst dish soap helps to remove oily buildup from your cookware, it can cause issues. This can combine with leftover oil and food to create deposits. Over time, mineral buildup can cause issues. Older plumbing systems can suffer from mineral deposits in the pipes. Hard water contains minerals which can leave scale forming on the inside of your pipes. If you are experiencing slow draining from your kitchen sink regularly, you may be suffering from buildup or scale. A professional can inspect to see if drainage cleaning is needed.

4. Clogged P Trap:

Located under your kitchen sink, the P trap is a curved pipe which contains a small amount of water to stop sewer gases from coming into your home. This curve can cause issues with buildup. Grease, food and soap can all get trapped in the P trap, causing a reduction in water flow. A partially blocked P trap may allow water to flow, but it can cause issues again as more buildup occurs. You may also experience bad odours. Some localized blockages can be cleared by cleaning the P trap. However, if the problem persists, further down the drain line may be the issue.

5. Incorrect Garbage Disposal Use:

If you have a garbage disposal in your kitchen, incorrect use can cause issues. Too much food waste can cause the disposal to become overwhelmed. Fibrous vegetables, coffee grounds, large amounts of starchy food and some other items can cause issues depending on the type of disposal. Eggshells and fibrous matter are commonly mentioned, but always follow the manufacturer’s guidelines on what you can put through. If you don’t run enough water through the disposal, it can cause issues getting food waste through.

6. Damaged/Corroded/Aged Pipes:

Sometimes the issue isn’t what you are putting down your kitchen sink but the pipes themselves. Older metal pipes can cause corrosion. This can cause a rough texture to form inside the pipe, causing oil to build up. Cracks, loose connections and misaligned pipes can also cause issues. Sometimes there may be a dip in the pipe causing wastewater and solid waste to pool. Whilst this can be cleaned, it won’t fix the structural issue. If the same section keeps getting blocked, a plumber may recommend drainage repairs.

7. Underlying Blockage:

Sometimes the blockage isn’t directly under your kitchen sink but further down the branch drain or main sewer line. Oily buildup, tree roots and other blockages can cause issues further down the drain line, causing slow drainage from your kitchen sink. Even if you clean the local drain. Look out for other signs. If you are experiencing bubbling, recurring backups or multiple slow drains, there may be an issue. A professional can inspect to find the blockage. This can then determine if drainage cleaning or plumbing repairs are needed.

Signs of a Recurring Drain Issue

Your kitchen sink won’t always become completely blocked. Often, small signs will occur.
Slow Draining Water: If you are constantly experiencing water pooling in your sink, there may be buildup or a partial blockage.
Bad Odours: Food waste, oil and other organic matter can cause a bad odour if it gets stuck in your drain or P trap.
Bubbling: If there are bubbling sounds after running water, there may be air trapped due to a partial blockage. Drainage or venting issues can cause odd sounds.
Back up: If you are experiencing backup there could be a major blockage. Don’t try to use your sink until you have found out what is causing it.
Same Sink Always Clogging: If you are constantly experiencing blockage, this means the original issue may not have been completely fixed. There could be an issue further down the drain line or it could be an issue with your plumbing.

How To Avoid Kitchen Sink Clogs

Simple habits can help to reduce the amount of waste going down your kitchen drain.

Don’t Put Oily Matter Down Your Drain:

Allow your oil and grease to cool and dispose of into the correct waste bin. Don’t rely on hot water or dish soap to flush it through your plumbing.

Sink Strainer

Fit a sink strainer to stop food, vegetable matter and other solid waste going down the drain. This should be emptied regularly.

Run Water Through Garbage Disposal

Follow the manufacturer’s guidelines on how much water to run through and how long to run. This will help to push food waste through.

Regularly Clean Sink Drain

Remove any visible food matter and residue. Check your sink strainer regularly.

Don’t Flush Large Food Matter

Fibrous vegetables, large food matter and excess starchy waste should be disposed of in the correct bin or compost. Your garbage disposal won’t be able to deal with all kitchen waste.

Whilst these habits can help improve your drain they won’t prevent all plumbing issues. Older pipes and underlying issues may need a professional.

Professional Drain Cleaning Solutions

If your home remedies aren’t working a professional drain company can help to clear your kitchen sink. The correct solution will depend on where the blockage is, the condition of your pipes and if it is an issue with your sink assembly or further down the drain.
Professional Drain Snake: A professional drain snake or auger can be used to reach blockages in your drain pipes. This uses a flexible cable to break through or retrieve buildup in your pipes, which wouldn’t be possible with basic plungers. This can help to clear compacted food waste, oil blockages and other stubborn matter.
Professional Drain Cleaning: Oily matter and food waste can build up along the inside of your drain pipes. Simply clearing the middle may not be enough if there is a large amount of residue.
Professional drain cleaning can help to clear any build up using the correct tools. Depending on the condition of your pipes and blockage a plumber may recommend mechanical cleaning.
P Trap Cleaning: If the blockage is in your P trap cleaning the curved pipes can help. A plumber can inspect your trap and clear any build up. They can also check the connections around the trap. They can also identify any loose connections, damaged seals, corrosion or leaks. If there are any worn or damaged parts, they can be repaired or replaced to help prevent this issue.
Drain Camera: If you are constantly having issues with your kitchen sink clogging it may be time to look further down the drain. A drain camera can be used to inspect the inside of accessible drain pipes. This can help identify any oily buildup, hidden blockage, damage to the pipes and other drainage issues. This will give the plumber a better idea of what is going on and if cleaning, repair or replacement is the best option.

Kitchen Sink Drain Replacement

Sometimes cleaning won’t be enough as the drain parts may be too damaged.
Cracked pipes, extreme corrosion, misaligned pipes and worn connections may need replacing. Continuing to clean a damaged drain won’t help with the structural issues.
A professional plumber can identify what parts need replacing. They can then remove the damaged parts and fit the correct new connections. This will help to prevent any leaks, improve drainage and give a more reliable connection to your kitchen plumbing.

When To Call A Professional Plumber

A single slow drain may not be a big issue, but if you are experiencing recurring blockages, you should contact a professional plumber. If you are experiencing any of the following issues:
Recurring Blockage: This means there is likely buildup in your drain or an underlying plumbing issue.
Multiple Slow Drains: If your kitchen sink, bathroom sink and other fixtures are all draining slowly, it could be an issue with a shared drain or main sewer.
Constant Bad Smell & Back Up: If you are experiencing constant bad smells and backups, it could be an underlying issue.
Visible Leaks & Damaged Pipes: If you are seeing water underneath your sink, corroded connections or damaged drain connections, you should have them checked.

Why Choose Rosedale Plumbing?

If your kitchen sink is constantly blocked, you will need a plumber who can find the cause and recommend the correct solution.
Rosedale Plumbing offers plumbing services to both residential and commercial clients across Toronto and the GTA. We can also help with plumbing in other areas of Ontario. Our plumbing team can help with blockages, cleaning, inspections and repairs.
We aim to find the cause of the issue and use the correct tools. If you need professional drainage cleaning, P trap repairs or further inspections we can help.