🚫 Blocked Drain? What to Do

A blocked drain is one of the most common plumbing issues, and the good news is many blockages can be cleared quickly. This guide walks you through DIY methods and tells you when to call a professional.

Identify the Type of Blockage

Single drain (e.g., sink, shower) is slow or blocked

• Likely cause: Hair, soap, grease, or debris in the trap
• Difficulty: Easy to clear yourself

Multiple drains (bathroom sink + shower + toilet)

• Likely cause: Blockage in the main drain line (tree roots, grease buildup, collapsed pipe)
• Difficulty: Professional equipment needed

Toilet is blocked (water level stays high)

• Likely cause: Paper/wipes/foreign object
• Difficulty: Usually easy with a plunger

Method 1: The Plunger (5 minutes)

For sinks, showers, and baths:

1. Fill the sink/tub with a few inches of water
2. Block any overflow hole with a wet cloth
3. Place the plunger firmly over the drain opening
4. Push down and pull up vigorously 15–20 times
5. Remove the plunger and check if water drains
6. Repeat if necessary

Success rate: 40–60% for shallow blockages.

Method 2: Remove the Trap (15 minutes)

Most effective for kitchen sinks:

1. Place a bucket under the pipe (water will spill)
2. Unscrew the curved section of pipe (the trap) by hand or with a wrench
3. Empty any water and debris into the bucket
4. Use your hands or a wire hook to pull out hair, soap, or grease buildup
5. Rinse the trap under hot water
6. Screw it back in place
7. Run water to test

Success rate: 80% - most blockages are in the trap.

Method 3: Baking Soda & Vinegar (30 minutes)

Chemical-free and safe:

1. Remove any standing water from the drain
2. Pour half a cup of baking soda down the drain
3. Pour half a cup of white vinegar after it (it will fizz)
4. Cover the drain opening with a plug or cloth
5. Leave for 15 minutes while the fizzing action breaks up debris
6. Boil a kettle of water and pour it down the drain
7. Test if water drains normally

Success rate: 30–50% for light blockages. Good for maintenance.

Method 4: Drain Snake/Auger (20 minutes)

For stubborn blockages:

1. Feed the snake into the drain slowly
2. Turn the handle (if manual) or switch on (if electric) to bore through the blockage
3. Feed more of the snake as you go
4. When you hit resistance, twist and push to break up the blockage
5. Pull the snake back out slowly
6. Run water to flush debris

Success rate: 70–85%. Rental cost: £30–50 from hardware stores.

Manual drain snake (cheapest option)

• Cost: £15–30
• Pro: Reusable, no power needed
• Con: More physical effort, less effective on deep blockages

Electric drain snake (easier)

• Cost: £50–150 to buy, £30–50 to rent
• Pro: Less effort, faster
• Con: Overkill for simple blockages

What NOT to Do

• Don't use strong chemicals (sulfuric acid) - they damage pipes and are hazardous. Reserve for professional use only.
• Don't force blocked toilets with a snake - you'll crack the bowl. Use a plunger or call a specialist.
• Don't ignore standing water - it indicates a blockage you should address soon.
• Don't pour grease down drains - it hardens and causes buildup. Wipe pans with paper towels instead.

When to Call a Professional

• Multiple drains in your home are slow/blocked (main line issue)
• Toilet is blocked and the plunger doesn't work
• Backing up into other fixtures (slow bathtub while sink drains fast = sewer line issue)
• Unpleasant smell coming from drains
• DIY methods didn't work after 2 attempts
• Water is backing up into your property (serious sewer problem)

Professional Drain Clearing Costs

• Standard blocked drain: £150–300
• Drain jetting (high-pressure water): £200–400
• CCTV drain survey (identify tree roots/damage): £250–500
• Emergency call-out (out of hours): +£50–100

Professional drain specialists have motorized equipment and cameras to diagnose issues you can't see. If your DIY methods fail, the cost is worth avoiding further damage.

Prevention Tips

• Use drain screens/hair traps in sinks and showers
• Never pour grease, coffee grounds, or food down drains
• Flush only toilet paper and human waste - not wipes, cotton pads, or feminine hygiene products
• Clean drain traps monthly to prevent buildup
• Have main drains professionally cleaned every 2–3 years if you have tree roots nearby

Why Drains Block in the First Place

Fat and grease are the biggest cause of kitchen drain blockages - they solidify as they cool, gradually narrowing the pipe until water can barely pass. Bathroom blockages are usually hair and soap residue building up in a similar way over time.

Outdoor drains block for different reasons, most commonly silt, leaves and debris washing in, or in older properties, tree roots finding their way into cracked or poorly jointed pipework.

Preventing Future Blockages

Avoid pouring fat and cooking oil down the sink - let it cool and put it in the bin instead. A simple drain guard over plugholes catches hair and food debris before it enters the pipework.

For outdoor drains, an occasional check and clear of leaves and debris from gullies, particularly in autumn, prevents the kind of build-up that leads to a full blockage further down the line.

When DIY Methods Aren't Enough

If a plunger, drain snake or chemical methods haven't cleared the blockage after a reasonable attempt, repeated forcing can risk damaging the pipework - at that point it's worth calling a professional rather than persisting.

Blockages that keep recurring in the same spot, despite regular clearing, usually indicate a structural issue like a cracked pipe or root ingress that DIY methods can't fix, and which a CCTV survey will identify.

Outdoor Drain Maintenance

Outdoor gullies and inspection chambers benefit from an occasional check, particularly after heavy rain or in autumn when leaves and debris are more likely to wash in and build up.

If water is regularly pooling around an outside drain, it's worth having it checked before winter, since a partial blockage that copes fine in dry weather can overflow completely during heavy rain.

Shared Drains and Neighbour Disputes

In terraced and semi-detached properties, drains are often shared between neighbouring homes, which means a blockage affecting your property might actually originate on a neighbour's side, or vice versa. This is worth establishing early, since it affects who's responsible for clearing it.

A CCTV drain survey is the clearest way to establish exactly where a blockage sits and whose responsibility it falls under, which can save a lot of back-and-forth with neighbours or your water company over who should be paying for the fix.

Signs of a Collapsed Drain

A collapsed or severely damaged underground drain shows different signs to a simple blockage - persistent bad smells even after clearing, ground that feels soft or has sunk slightly above the drain run, and blockages that return within days of being cleared are all warning signs worth taking seriously.

This is a more significant repair than a standard blockage clearance, typically involving excavation or pipe relining, and is exactly the kind of issue a CCTV survey is designed to identify clearly before any digging starts, so you know the full scope of work needed upfront.

Quick Questions

Are chemical drain cleaners safe to use regularly? Occasional use is generally fine, but frequent use can damage older pipework over time - mechanical clearing is usually the safer long-term option.

How much does a CCTV drain survey cost? Pricing depends on the length and accessibility of the drain run - we'll confirm this upfront before carrying out any survey.

Most blocked drains can be cleared with the right method and a bit of patience, but knowing when to stop and call a professional saves you time, effort, and the risk of making things worse. If in doubt, a quick call to us costs nothing to ask about, and we'd always rather advise you honestly than have you struggle with something that needs proper equipment.

Key Takeaways

• Most single-drain blockages are in the trap - remove and clean it
• Plungers work 40–60% of the time for sinks and baths
• Drain snakes are effective for stubborn blockages and cost £30–50 to rent
• Multiple blocked drains indicate a main sewer line issue - call a specialist
• Prevention (screens, no grease, proper flushing) is cheaper than emergency clearing