Blocked drains are a headache no one wants to deal with. Whether it’s water pooling in your sink, unpleasant odours in the bathroom, or your garden drain overflowing after rain, these Causes of Blocked Drains issues rarely fix themselves and can quickly turn into a bigger and messier problem. Understanding what causes drain blockages in the first place can help you prevent them, saving time, money, and stress. At Drainage Warrington, we’ve seen it all—and we’re here to help you avoid the most common culprits.
1. Grease, Fat, and Cooking Oil
One of the top culprits behind blocked kitchen drains is grease. When you wash up after cooking, the oils, fats, and grease might look like they’re going down the plughole just fine. But once they cool down, they solidify and stick to the inside of your pipes. Over time, this sticky build-up narrows the drain passage, eventually causing a full blockage. Causes of Blocked Drains. Even hot water doesn’t always fix it—it might temporarily shift the grease, but it reforms further down the pipe.
Tip: Always wipe greasy pans with kitchen roll before washing and use a fat trap or container for used oil.
2. Hair and Soap Scum
Hair may seem harmless, but when it mixes with soap, shampoo, or toothpaste residue, it forms a tangled mess that clogs bathroom drains. This usually builds up in shower or bath plugholes and slowly causes water to drain more slowly, until it stops completely.
Tip: Use a hair catcher over the drain and clean it regularly to stop build-up.
3. Wet Wipes and Sanitary Products
Even if the packet says “flushable,” wet wipes don’t break down in the same way toilet paper does. These items get caught in the pipes and quickly create blockages, especially when mixed with fats or hair. Sanitary products, cotton buds, and nappies should never be flushed, as they absorb water, expand, and can block even large drainage pipes.
Tip: Always bin these items instead of flushing them down the toilet.
4. Food Waste: Causes of Blocked Drains
Even with a sink strainer, bits of food can slip through. Coffee grounds, rice, pasta, eggshells, and vegetable peels are common offenders. They don’t always break down quickly and tend to settle in U-bends or pipe joints. Combined with grease, these can lead to stubborn blockages that need professional attention.
Tip: Scrape plates into the bin and avoid disposing of food waste down the sink.
5. Tree Roots: Causes of Blocked Drains
Outdoors, one of the biggest hidden dangers to your drainage system is tree roots. Roots naturally seek moisture and can grow into pipe joints or cracks, causing blockages and even structural damage. This issue isn’t visible until your drain starts overflowing or draining slowly, and usually requires a CCTV survey to diagnose.
Tip: Keep trees planted away from underground drainage systems and monitor old pipework for recurring issues.
6. Leaves and Outdoor Debris
In autumn especially, leaves, twigs, and mud can clog external drains and gullies. When these blockages happen, they often cause rainwater to back up into the driveway or garden. It may seem minor at first, but it can lead to damp problems if the overflow reaches your home.
Tip: Regularly clean outdoor drains and use grates or guards to trap debris before it enters the system.
7. Poor Pipe Installation or Structural Issues
Sometimes, the problem isn’t what goes down the drain—it’s the pipework itself. Misaligned joints, broken pipes, or poor installation can create weak spots where waste accumulates. Over time, these areas become prone to repeated blockages and may even collapse if left unchecked.
Tip: If you’re constantly unblocking the same drain, get a professional inspection done to check the condition of your pipes. At Drainage Warrington, we offer full drain surveys to find and fix the root of the problem.
8. Soap Residue and Limescale
In areas with hard water, soap and minerals from the water can combine to form limescale inside your pipes. This crusty build-up reduces water flow and traps debris, making clogs more likely over time.
Tip: Consider using water softeners or switching to soap-free cleansers to reduce residue in your pipes.
How to Spot a Blocked Drain Early: Causes of Blocked Drains
Here are the signs to look out for:
- Gurgling noises from plugholes
- Bad smells around sinks or drains
- Water is draining slowly or backing up
- Overflowing drains outside
- The toilet water is rising higher than usual
The earlier you catch the problem, the easier—and cheaper—it is to fix.
When to Call a Professional
While minor clogs can often be cleared with DIY methods like plungers or natural cleaners, recurring or stubborn blockages usually need a professional solution. Drainage Warrington uses high-pressure jetting, CCTV inspections, and specialist techniques to identify and clear the problem safely and effectively.
Final Thoughts
Blocked drains are never pleasant, but they’re also rarely a surprise. With a little prevention and an understanding of the most common causes, you can keep your home’s drainage system running smoothly.
Avoid flushing the wrong things, watch what goes down your sink, and keep an eye on outdoor drains—and if you do run into trouble, don’t wait. Contact Drainage Warrington for fast, expert help before a small issue becomes a major one.
