3 Steps to Clear a Blocked Outside Drain (And When to Call a Pro)
Are you seeing standing water in the garden or sewage backing up? Don’t panic – we’ll explain clearly what to do if your outside drain is blocked. For over 20 years, Drainflow has been the go-to expert for drain clearance across Bedfordshire, Hertfordshire and Buckinghamshire. We have seen every type of blocked drain outside, so we know exactly how to tackle them.
While we are always ready to send our drain clearance team if things get messy, we want to save you the call-out if possible. We’ve drawn up a simple action plan to help you clear the blockage yourself, along with guidance as to when you should stop and call the pros.
Quick Guide – 3 Steps to Clear Your Drain
- Diagnosis (is it the private or public drain?)
- Hot Water Flush (for grease and fat)
- Rodding (for solid debris)
The DIY Action Plan – How to Clear Your Drain Safely
Here is the exact process we recommend homeowners follow before calling for backup.
Step 1 – Check Who is Responsible
First, let’s save you some effort. Is the drain shared with a neighbour? If so, stop. In the UK, shared “lateral drains” are the water company’s job to fix. But if the drain sits inside your garden and serves only your house, it’s down to you.
Step 2 – Dissolve the Grease
If the blockage is soft and looks like fat, heat is the best way to tackle it. Carefully pour a kettle of boiled water down the drain This will start to liquefy the grease, allowing it to flush away.
Add soda crystals followed by hot water for extra cleaning power. If the water drains away, keep flushing with hot water to clear the drain pipe.
Step 3 – Use Drain Rods for Hard Blockages
If the water doesn’t work, it’s likely that you have a solid obstruction like leaves, wet wipes, or silt. In which case you will need drain rods – these are available at most hardware shops or online.
Insert the rods and use a firm plunging action to break up the solid mass. Rotate them clockwise as this tightens the screw connections. Rotating the other way will lose your equipment down the drain.
Warning – Never force the rods if they hit something rock hard. This could be a tree root or a collapsed pipe. Forcing it could crack the pipework.
Action Plan Failed? Here’s Why You Need to Stop
If you have followed our 3-step plan and the water level still hasn’t dropped, then you’re dealing with a complex blockage that’s probably beyond DIY methods. Continuing to force drain rods against an obstruction that won’t move is dangerous – it can fracture pipes or result in the rods snapping off underground.
The Hidden Causes of Stubborn Blockages
DIY tools are designed for soft blockages. They’re just not made to tackle structural issues. If your drain is still blocked, it’s probably because of:
- Tree Root Ingress – Roots love drains because of the moisture they provide. They will make their way in via a crack and can crush or fill a pipe. Rods cannot cut through them.
- Scale & Fatbergs – Over years, scale builds up like concrete. This requires high-pressure drain jetting to scour the pipe walls clean.
- Collapsed Pipe – If the ground has shifted, the pipe may be broken. Pushing a rod will only push soil into the pipe.
When to Call Drainflow
If DIY methods fail, the blockage seems deep, or you face any of these scenarios, it’s time for professional help:
- Suspected tree root intrusion.
- Persistent unpleasant smells.
- Signs of damaged pipes.
Drainflow’s drain clearance team has the tools and expertise to diagnose and fix stubborn drain blockages, leaving you confident that you have a free-flowing drainage system. Drainflow will normally use two approaches when an outside drain is blocked:
- CCTV Drain Survey – A remote-controlled CCTV camera is inserted into your drains, providing a real-time video feed that allows us to pinpoint any issues like cracks, blockages, or structural damage. This detailed inspection ensures accurate diagnosis and targeted solutions for any drainage problems.
- Drain Jetting – High-pressure water jets are directed into the pipes to dislodge and clear debris, grease, tree roots, and other obstructions. This restores the flow to your drainage system and helps prevent future blockages.
Case Study – Clearing a Severe Foul Drain Blockage in Hemel Hempstead
When a drain emergency hits, you need a team with the right heavy-duty kit. The Drainflow team recently handled an urgent call from a customer in Hemel Hempstead; their foul drain had backed up completely, threatening a residential site with raw sewage.
The Situation
The customer was facing a major foul blockage. When this kind of thing happens, acting fast is essential in order to prevent property damage and risks to health.
Our Response:
- Arrival & Containment – We arrived promptly with a high-capacity vacuum tanker to immediately pump out the standing sewage, making the area safe and accessible.
- Fast Diagnosis – A secondary van contained the equipment for a CCTV drain survey, allowing us to pinpoint the exact location and nature of the blockage in the drain.
- High-Pressure Solution – We used high-pressure drain jetting to blast through the blockage. This scours the pipe walls clean, removing the fats and built-up limescale that cause repeat issues.
The Result
In under an hour, the drain was free flowing. We provided the customer with CCTV footage as visual proof that the structural integrity of the pipe was sound, and that the blockage was 100% gone.
Blocked Outside Drains FAQs
If you have a blocked outside drain, you probably have lots of questions. Here are some answers to the questions we hear most regularly from our customers.
A blockage will show itself with a slow build-up of water. Collapsed pipes cause sinkholes to appear in your garden, or cracks in brickwork nearby. This is a problem that needs immediate specialist attention to prevent the subsoil from washing away and destabilising your property.
Standard policies cover “accidental damage” to underground pipes, such as root intrusion or a pipe collapse, but they rarely cover general maintenance or blockages caused by waste. Check your insurance policy for ‘Home Emergency Cover, which often provides a specific allowance for rapid drain clearance.
If we clear roots using high-pressure jetting, they will eventually return unless the pipe is repaired. Roots enter through tiny cracks seeking moisture. To solve this permanently, we recommend a patch lining, which seals the pipe from the inside and prevents roots from finding a way back in.
No. It can also indicate a failed ‘P-trap’ or a perished seal on a valve. If the water is flowing freely but the smell doesn’t shift, the system may be venting sewer gases incorrectly. We’ll be able to tell you what the cause is.
If sewage is backing up into your baths or showers, or if multiple toilets won’t flush at the same time, your foul drain has failed. That is an emergency. Likewise, if you see foul water pooling near your house foundations or an electrical box, stop using all water and call us immediately. If the waste is coming in instead of going out, you need to move fast to avoid property damage.
Drainflow Solves Drainage Problems
We hope this guide has helped you to solve your drain blockage yourself. If your DIY efforts haven’t worked, don’t risk damaging your pipework by forcing it. Allow Drainflow to solve the problem cleanly and efficiently with the latest CCTV and high-pressure jetting technology which with tackle the most stubborn external blockages.
Ready to clear the blockage? If you need professional backup, we are ready to help. We don’t charge a call-out fee, so it costs nothing to get an expert opinion and no obligation quote – 01525 718500