News & TipsHow to Unblock a Badly Blocked Drain
There are few household headaches quite as frustrating, or as unpleasant, as a badly blocked drain. Whether it’s your kitchen sink refusing to empty or a shower tray rapidly turning into a foot bath, drainage issues can disrupt daily life and leave you battling bad odours, standing water, and even potential flooding. But Why Do Drains Get Blocked in the first place? Understanding the common causes behind these blockages is the first step to fixing, and preventing, them.
In this comprehensive guide, we’ll explore the causes of serious drain blockages, how to identify the severity of the problem, and step-by-step solutions you can try at home—along with advice on when it’s time to call in the professionals.
Understanding Why Drains Get Blocked
Before you reach for the plunger, it helps to understand what causes drains to clog in the first place. In most UK households, common culprits include:
- Fat, oil and grease (FOG): These substances might go down your kitchen sink as liquids, but they solidify as they cool, sticking to the inside of your pipes like glue.
- Hair and soap scum: A classic combination that builds up over time in shower and bathroom drains.
- Food waste and coffee grounds: Even with a sink strainer, bits of food can sneak through and create obstructions.
- Wet wipes and sanitary products: These should never be flushed, despite what the packaging might suggest.
- Tree roots or pipe collapse: In more severe cases, external drains may become blocked due to root ingress or broken underground pipes.
Signs Your Drain Is Badly Blocked
It’s important to differentiate between a mildly sluggish drain and a serious blockage. Here’s how to tell the difference:
- Water drains away very slowly or not at all.
- Gurgling sounds from plugholes or toilet bowls.
- Unpleasant odours rising from the drains.
- Water backing up into sinks, baths, or toilets.
- Overflowing gullies or external drain covers.
If you’re experiencing more than one of these symptoms at once, you’re likely dealing with a bad blockage—and it’s time to act fast.
Step-by-Step: How to Unblock a Badly Blocked Drain
1. Safety First
Before tackling any drain, put on rubber gloves. If you’re working with chemicals or external drains, safety goggles and a face mask can also be useful.
2. Try Boiling Water
Simple, but surprisingly effective for grease-related blockages. Boil a full kettle of water and slowly pour it down the drain in stages, allowing it to sit for a few seconds between pours.
Note: Avoid this method if your plumbing includes PVC pipes, as boiling water can damage the plastic.
3. Use a Plunger
A proper drain plunger—not a toilet plunger—can help dislodge clogs using suction. Fill the sink or basin with enough water to cover the plunger, then plunge vigorously up and down for about 30 seconds. If successful, you should see the water begin to drain.
4. Try a Drain Snake or Hand Auger
For tougher clogs deeper in the pipe, a drain snake (also known as a plumber’s snake) can reach and break up the blockage. Slowly insert the coil into the drain, twisting as you go. When you hit resistance, rotate the snake to hook or break up the clog, then pull it out slowly.
You might be surprised—or disgusted—by what comes out.
5. Use a Natural Drain Cleaner (Baking Soda & Vinegar)
If you’re trying to avoid harsh chemicals, this method is eco-friendly and safe for most pipes.
- Pour 1/2 cup of baking soda down the drain.
- Follow with 1 cup of white vinegar.
- Let it fizz for 10–15 minutes.
- Flush with hot (not boiling) water.
This combination can help dissolve soap scum, minor grease, and odours.
6. Chemical Drain Cleaners (With Caution)
These can be effective, but should be used sparingly and with care, as they can damage your pipes and are harmful to the environment.
- Always read and follow the manufacturer’s instructions.
- Never mix different chemical cleaners—it can produce toxic fumes.
- Wear protective gear when handling.
7. Check the U-Bend (Trap)
Under the kitchen or bathroom sinks, you’ll find a U-shaped pipe (the trap). It often catches debris before it reaches further into the system.
- Place a bucket underneath to catch water.
- Unscrew the trap (usually hand-tight).
- Clean out any gunk and reassemble.
Make sure all seals are tight before running water again.
How to Deal With External Drain Blockages
If the issue lies outside your home—such as a blocked manhole or gully—extra precautions are needed.
- Lift the drain cover carefully using a suitable tool (gloves and a crowbar or screwdriver).
- Use a rod or jet washer to clear the blockage if visible.
- Be aware of your responsibility: If the blockage is within your property boundary, it’s usually your responsibility to fix. Beyond that, it may be up to your water provider.
If there’s sewage backing up, or a significant blockage you can’t see or reach, do not attempt to fix it yourself. It’s time to call the professionals.
Prevention Tips: Keeping Drains Flowing Freely
Once you’ve cleared a blockage, take steps to prevent the problem from coming back:
- Install drain guards to catch food, hair, and debris.
- Never pour fats or oils down the sink—use a separate container and dispose in the bin.
- Run hot water down the kitchen sink regularly to help melt grease.
- Clean plugholes and gullies weekly.
- Avoid flushing non-flushables—even if they claim to be biodegradable.
When to Call in the Experts
Sometimes, DIY just isn’t enough. If you’ve tried all of the above and the blockage remains—or keeps recurring—it’s time to call a professional drainage service.
Signs you need help:
- Repeated blockages in the same drain.
- Flooding or water damage.
- Foul smells that won’t go away.
- Blocked drains affecting multiple fixtures.
- Signs of rodent activity or collapsed pipework.
Professional Help You Can Trust – Drainage Bristol
If you’re in the Bristol area and battling a drain blockage you just can’t budge, the experienced team at Drainage Bristol is here to help. With state-of-the-art equipment, 24/7 emergency response, and transparent pricing, they’ve earned their reputation as one of the region’s most trusted drainage specialists.
Whether it’s a stubborn sink, overflowing external gully, or a backed-up sewer line, Drainage Bristol offers:
- High-pressure drain jetting
- CCTV drain surveys
- Drain excavation & repair
- Emergency drain clearance
- Preventative maintenance plans
Don’t let a blocked drain turn into a costly disaster. Call Drainage Bristol today and get your home flowing smoothly again.
Available: 24 hours a day, 7 days a week
Final Thoughts
Badly blocked drains aren’t just inconvenient—they can pose health hazards and cause serious damage if left untreated. Fortunately, with the right approach and some know-how, you can resolve many blockages yourself. And when you can’t, trusted professionals like Drainage Bristol are just a phone call away.
