Why Is My Drain Blocked? Common Causes and Fixes for Norwich Homes (2026)

The Quick Answer

Most blocked drains in Norwich homes are caused by one of six things: fat and grease buildup, hair and soap scum, foreign objects, tree root intrusion, collapsed or damaged pipes, or a blockage in the main sewer connection. Some of these you can clear yourself with basic tools. Others require professional drainage equipment and expertise.

This guide explains how to identify what is causing your blocked drain, what you can safely fix yourself, and when the problem needs a professional drainage contractor - particularly relevant for Norwich's older properties with original Victorian and Edwardian drainage.

The 6 Most Common Causes of Blocked Drains in Norwich

1. Fat, Oil, and Grease Buildup (FOG)

The single most common cause of kitchen drain blockages. When you pour cooking fat, oil, or grease down the sink, it solidifies as it cools and coats the inside of your pipes. Over time, this buildup narrows the pipe until water can no longer pass.

In Norwich's older properties with original cast iron or clay drainage pipes, the rougher interior surface gives fat more to cling to, accelerating buildup compared to modern smooth plastic pipes.

Signs it is FOG: Slow-draining kitchen sink, gurgling sounds, and a blockage that gets gradually worse over weeks rather than appearing suddenly.

2. Hair and Soap Scum

The most common cause of bathroom drain blockages. Hair washed down shower and bath drains combine with soap scum to form dense clumps that catch everything else flowing past. Bathroom sinks, shower drains, and bath drains are all vulnerable.

Signs it is hair and soap: Slow-draining shower or bath, water pooling around your feet in the shower, and a blockage in the bathroom rather than the kitchen.

3. Foreign Objects

Items that should never go down a drain but frequently do: wet wipes (even "flushable" ones), sanitary products, cotton buds, dental floss, children's toys, and excessive toilet paper. These do not break down and create blockages, often in the toilet or the main soil pipe.

"Flushable" wet wipes are a particularly common culprit in 2026. Despite the marketing, they do not break down like toilet paper and are a leading cause of blockages in both household drains and the wider sewer network.

Signs it is a foreign object: A sudden complete blockage rather than a gradual slowdown, often in the toilet, sometimes after a specific event.

4. Tree Root Intrusion

A significant cause of blocked drains in Norwich's established residential areas with mature trees - parts of Thorpe Hamlet, Eaton, and the older suburbs with Victorian and Edwardian housing.

Tree roots are drawn to the moisture and nutrients in drainage pipes. They enter through tiny cracks or joints in older pipes, then grow inside the pipe, eventually forming a dense mass that blocks flow and catches debris. Clay pipes common in older Norwich properties are particularly vulnerable because their jointed construction provides entry points.

Signs it is tree roots: Recurring blockages that return after clearing, multiple drains affected, blockages in a property with mature trees nearby, and gurgling from drains when using water elsewhere in the house.

5. Collapsed or Damaged Pipes

Older drainage pipes degrade over time. Clay pipes crack, cast iron corrodes, and ground movement can shift or fracture pipe sections. A collapsed or significantly damaged pipe creates a blockage that cannot be cleared by conventional rodding because the pipe structure itself is the problem.

Norwich has significant numbers of properties with original Victorian and Edwardian drainage that is now well over a century old. At this age, pipe degradation is a genuine and common cause of drainage problems.

Signs it is a damaged pipe: Persistent blockages that return immediately after clearing, multiple drainage points affected, damp patches or sinkholes in the garden above the drain line, and rat activity (rats often enter properties through broken drains).

6. Main Sewer or Shared Drain Blockage

Sometimes the blockage is not in your private drainage but in the shared or main sewer connection. If multiple properties are affected, or if the blockage is downstream of where your private drainage meets the main sewer, the responsibility may lie with Anglian Water rather than you as the homeowner.

Signs it is the main sewer: Multiple drains in your property backing up simultaneously, neighbours experiencing similar problems, and sewage backing up into the lowest drainage points (ground floor toilets, gullies).

What You Can Fix Yourself

Some blocked drains are genuinely DIY-fixable. Here is what you can safely attempt before calling a professional.

For slow kitchen sinks (FOG buildup):

Boiling water is the first thing to try. Pour a kettle of boiling water down the drain in two or three stages, allowing it to work between pours. This can melt and clear early-stage fat buildup.

A mixture of bicarbonate of soda and white vinegar can help with minor grease blockages. Pour half a cup of bicarbonate of soda down the drain, followed by half a cup of white vinegar. Leave for 30 minutes, then flush with boiling water. This is a mild approach that works on minor buildup but will not clear a fully blocked pipe.

A plunger creates pressure that can dislodge blockages close to the drain opening. Ensure there is enough water in the sink to cover the plunger head, and plunge firmly several times.

For bathroom drains (hair and soap):

A drain snake or even a straightened wire coat hanger with a small hook bent into the end can physically pull out hair clumps near the drain opening. This is often the most effective approach for shower and bath drains.

Remove and clean the drain trap if accessible. The U-bend under sinks catches debris and can be unscrewed, emptied, and cleaned - though have a bucket ready for the water it contains.

What to avoid:

Chemical drain cleaners should be used sparingly if at all. They can damage older pipes - a real concern in Norwich properties with original drainage - and are harmful to the environment. Repeated use of caustic chemical cleaners can accelerate the degradation of older cast iron and clay pipes.

Do not attempt to clear a blockage by forcing high-pressure water into a drain you suspect may be damaged or collapsed. This can worsen the damage.

DIY not working? KiKK clears blocked drains across Norwich - professional drainage equipment, CCTV drain surveys, and honest advice. Get a Free Quote →

When to Call a Professional Drainage Contractor

Some blocked drains need professional equipment and expertise. Call a drainage professional when:

The blockage keeps coming back. A blockage that returns within days or weeks of clearing indicates an underlying problem - tree roots, a damaged pipe, or a partial collapse - that DIY clearing cannot resolve. The recurring nature is the signal that the problem is structural rather than a simple buildup.

Multiple drains are affected. If sinks, toilets, and gullies are all backing up, the blockage is in the main drainage run rather than an individual fixture. This requires professional location and clearing.

You suspect a collapsed or damaged pipe. Damp patches in the garden, sinkholes above the drain line, rat activity, or persistent blockages that resist clearing all suggest pipe damage. This needs a CCTV drain survey to diagnose and professional repair to fix.

Sewage is backing up. Sewage backing up into your property is a health hazard and requires immediate professional attention. Do not attempt to clear this yourself.

The blockage is in an inaccessible location. Blockages deep in the drainage run, in the main soil pipe, or in underground sections that you cannot reach safely need professional drainage rods and high-pressure jetting equipment.

You have an older Norwich property with original drainage. Properties with Victorian or Edwardian clay and cast iron drainage are more prone to structural problems. If you have an older Norwich home with recurring drainage issues, a professional CCTV survey can identify whether the underlying drainage needs repair or replacement rather than repeated clearing.

How Professional Drain Clearing Works

Understanding what a professional drainage contractor does helps you know what to expect and what you are paying for.

CCTV drain survey

A camera on a flexible rod is fed into the drainage system to visually inspect the inside of the pipes. This identifies exactly what is causing the blockage and where it is located - whether it is a simple buildup, tree roots, a crack, or a collapse. The survey eliminates guesswork and means the right repair is carried out rather than a temporary clear.

For Norwich properties with older drainage, a CCTV survey is particularly valuable because it reveals the actual condition of pipes that may be over a century old.

High-pressure water jetting

Professional jetting equipment uses high-pressure water to clear blockages and clean the inside of pipes. It is significantly more effective than domestic methods for FOG buildup, scale, and debris. Jetting clears the pipe back to its full diameter rather than just punching a hole through the blockage.

Drain rodding

Flexible rods with various attachments are fed into the drain to physically break up and clear blockages. Effective for many blockage types and often used in combination with jetting.

Root cutting

For tree root intrusion, specialist cutting equipment removes the roots from inside the pipe. Note that root cutting clears the immediate blockage but the roots will regrow unless the pipe entry point is repaired - which is why diagnosis of the underlying cause matters.

Pipe repair and relining

Where the underlying problem is a damaged or collapsed pipe, the repair options include excavation and replacement of the damaged section, or no-dig pipe relining where a new pipe lining is installed inside the existing pipe. The right approach depends on the extent and location of the damage, which the CCTV survey identifies.

Preventing Blocked Drains in Your Norwich Home

Prevention is cheaper than repair. These habits significantly reduce the risk of blocked drains.

In the kitchen: Never pour fat, oil, or grease down the sink. Let it cool and solidify, then scrape it into the bin. Wipe greasy pans with kitchen paper before washing. Use a sink strainer to catch food debris.

In the bathroom: Use drain guards to catch hair in showers and baths. Clean them regularly. Do not flush wet wipes, cotton buds, sanitary products, or anything other than toilet paper - regardless of "flushable" labelling.

For tree roots: If you have mature trees near your drainage and an older property, consider a periodic CCTV survey to catch root intrusion early before it causes a major blockage. Early detection allows root removal and pipe repair before a collapse occurs.

For older properties: If you have a Norwich property with original Victorian or Edwardian drainage, a one-off CCTV survey gives you a baseline understanding of your drainage condition. Knowing the state of your pipes lets you plan repairs proactively rather than reacting to emergencies.

General: Run hot water down kitchen drains regularly to keep fat from accumulating. Address slow drains promptly rather than waiting for a complete blockage - a slow drain is an early warning.

Who Is Responsible for a Blocked Drain in Norwich?

Drainage responsibility can be confusing. Here is the general position.

Your responsibility: Drains within the boundary of your property that serve only your property are your responsibility as the homeowner. This includes the drainage from your sinks, toilets, and gullies up to the point where it connects to a shared or public sewer.

Anglian Water's responsibility: The public sewer network and, since 2011, most shared drains and lateral drains that serve multiple properties. If your blockage is in a shared drain or the main sewer, Anglian Water is typically responsible for clearing it.

Shared drains: Drains that serve more than one property are usually the responsibility of the water company (Anglian Water in Norwich) following the 2011 transfer of private sewers. If you share drainage with neighbours and the blockage is in the shared section, contact Anglian Water.

The practical approach: If you are unsure whether a blockage is your responsibility or Anglian Water's, a professional drainage contractor can identify the location of the blockage and advise on responsibility. If it turns out to be Anglian Water's, they will tell you - and a reputable contractor will not charge you to clear a blockage that is the water company's responsibility.

FAQ

Why does my drain keep blocking?

A drain that repeatedly blocks usually has an underlying structural problem - tree root intrusion, a damaged or partially collapsed pipe, or a section where the pipe has sagged and collects debris. DIY clearing addresses the symptom but not the cause, which is why the blockage returns. A CCTV drain survey identifies the underlying problem so it can be properly fixed.

Can I clear a blocked drain myself?

Minor blockages near the drain opening - early FOG buildup, hair clumps in bathroom drains - can often be cleared with boiling water, a plunger, or a drain snake. Blockages that are deep in the system, recurring, affecting multiple drains, or involving sewage backup need professional equipment and should not be attempted yourself.

How much does it cost to clear a blocked drain in Norwich?

Costs vary depending on the blockage location and severity. A straightforward blockage clearance is typically less expensive than a job requiring CCTV survey and structural repair. KiKK provides clear quotes after assessing the specific problem - contact us for a quote for your situation.

Are chemical drain cleaners safe for my pipes?

Chemical drain cleaners can damage older pipes, which is a real concern in Norwich properties with original cast iron and clay drainage. Repeated use accelerates pipe degradation. They are also harmful to the environment. For older properties especially, mechanical clearing (plunging, snaking, professional rodding and jetting) is safer than chemical cleaners.

My whole house has slow drains - what does that mean?

When multiple drains throughout the property are slow or backing up, the problem is usually in the main drainage run rather than an individual fixture. This often indicates a blockage or damage in the main soil pipe or the connection to the sewer, and needs professional diagnosis.

Do I need a CCTV drain survey?

A CCTV survey is worthwhile when you have recurring blockages, suspect pipe damage, are buying an older property, or want to understand the condition of original Victorian or Edwardian drainage. It eliminates guesswork and ensures the right repair is carried out. For a one-off slow drain that clears easily, a survey is not necessary.

Who do I call for a blocked drain in Norwich?

For blockages that are your responsibility as a homeowner, a local drainage contractor like KiKK can clear and repair them. For blockages in shared drains or the main sewer, contact Anglian Water. If you are unsure, a contractor can identify the blockage location and advise on responsibility.

Why are wet wipes a problem if they say flushable?

"Flushable" wet wipes do not break down like toilet paper. They retain their structure in the drainage system and catch other debris, forming blockages. They are a leading cause of household and sewer blockages despite the flushable labelling. Dispose of all wet wipes in the bin, not the toilet.

Can tree roots really block my drain?

Yes. Tree roots are drawn to the moisture in drainage pipes and enter through cracks and joints, particularly in older clay pipes. They grow inside the pipe, forming a dense mass that blocks flow. This is a common cause of recurring blockages in Norwich's established residential areas with mature trees. Clearing the roots provides temporary relief, but the pipe entry point needs repair to prevent regrowth.

Get Help With Your Blocked Drain in Norwich

If you have a blocked drain that DIY methods have not cleared, or a recurring problem that suggests an underlying issue, KiKK provides professional drainage services in Norwich and across Norfolk.

We diagnose the actual cause - using CCTV surveys where needed rather than guessing - and carry out the right repair. For older Norwich properties with original drainage, we have the experience to identify whether you need a simple clear or a more substantial repair, and we give you honest advice either way.

Kallan responds to all enquiries within 24 hours. We provide clear quotes after assessing the problem, with no obligation.

Blocked drain in Norwich? Get it diagnosed properly, not just cleared temporarily. KiKK provides professional drainage services with CCTV surveys and honest advice. Call 01603 381016 or use the form. Get a Free Quote →

KiKK Groundworks provides drainage, blocked drain clearing, CCTV surveys, driveways, block paving, and groundworks across Norwich and Norfolk. NRSWA accredited, fully insured, owner-led.