The short answer
It depends where the problem is. A plumber handles the pipework inside your home — taps, traps, waste pipes, toilets, leaks and slow sinks — and can clear most blockages up to the point where waste leaves the building. A drainage company specialises in the underground drains and sewers beyond the property, with high-pressure jetting, CCTV survey cameras, root cutters and the kit to deal with collapses, root ingress and recurring blockages. For a single blocked sink or toilet, a plumber is usually fine and often cheaper. For a blockage in an outside drain or manhole, a smell or backing-up that affects several fittings, or anything needing a camera survey or jetting, a specialist drainage company is better equipped. Many firms do both, so describing the symptoms clearly when you call gets the right trade to your door.
Plumbers and drainage companies overlap, but they are tooled for different jobs. The deciding factor is usually whether the trouble is inside the house or out in the underground drains. Here is how to tell.
Plumber vs drainage firm
- PlumberInternal pipework and fittings
- Drainage companyUnderground drains and sewers
- Plumber kitPlunger, hand snake, rods
- Drainage kitJetter, CCTV, root cutters
- Call drainage forManholes, recurring, smells, surveys
What each trade covers
A general plumber works on the water and waste systems within the property: supply pipes, taps and valves, traps under sinks and basins, toilet mechanisms, internal waste runs and leaks. Plumbers routinely clear blocked sinks, basins, baths, showers and toilets, and carry plungers, hand augers and basic rods. If the blockage is in the trap or a short internal waste pipe, a plumber will usually sort it on the first visit.
A drainage company focuses on the drains that carry waste away underground — the pipework from the property boundary to the public sewer, plus inspection chambers and manholes. Their vans carry high-pressure water jetters, CCTV cameras for surveys, electro-mechanical root cutters and the equipment for relining or excavation. When a blockage is beyond the building, affects multiple fittings, or keeps coming back, that specialist kit is what clears it and identifies the cause.
| Factor | Plumber | Drainage company |
|---|---|---|
| Focus | Inside the property | Underground drains and sewers |
| Typical jobs | Sinks, toilets, traps, leaks | Manholes, blocked outside drains |
| Equipment | Plunger, hand snake, rods | Jetter, CCTV camera, root cutters |
| Recurring blockages | Limited tools | Jetting and surveys |
| Investigates cause | Surface only | CCTV survey identifies cause |
| Repairs pipe damage | Internal pipework | Relining, excavation, patch repair |
Indicative split for guidance. Many firms offer both plumbing and drainage.
How to decide who to call
Use the symptoms as your guide. A single slow or blocked sink, basin, bath or toilet — with everything else draining normally — is an internal problem and a plumber is the natural first call. If you have already tried a plunger and a hand snake without luck, a plumber has slightly heavier tools and the experience to clear it.
Call a drainage company when the signs point underground: water backing up out of a gully or manhole, a foul smell outside, more than one fitting draining slowly at once, gurgling toilets, or a blockage that returns within days or weeks of being cleared. These suggest the problem is in the underground run and needs jetting or a camera to find and fix it. A drainage firm is also the right choice when you suspect root ingress, a collapsed pipe or a soakaway problem, because diagnosing those needs a CCTV survey.
Cost, credentials and getting it right
For straightforward internal blockages a plumber is often the cheaper option, charged by the hour or as a fixed call-out, because the job is quick and needs no specialist machinery. Drainage work that involves jetting, a CCTV survey or excavation costs more because of the equipment and time involved, but it is the appropriate spend when the cause is underground — paying a plumber repeatedly to clear a drain that keeps blocking usually works out dearer than one drainage visit that finds and fixes the root cause.
Whichever trade you call, check credentials and reviews. Look for membership of a recognised body or a verified listing on a platform such as Checkatrade, confirm whether the quote is fixed or hourly and what it includes, and ask whether a CCTV survey is recommended for a recurring problem so you are diagnosing rather than just clearing. Describe the symptoms accurately on the phone — which fittings are affected, whether water backs up outside, and how often it recurs — so the right trade arrives with the right equipment.
Reading the symptoms before you call
A few minutes of observation before you phone anyone helps you describe the problem and reach the right trade. Note exactly which fixtures are affected: a single slow basin points inside to a plumber, whereas the kitchen sink, downstairs toilet and washing machine all draining slowly together points to the shared underground run and a drainage company. Listen for gurgling, which suggests trapped air from a blockage further down, and check outside whether any gully or inspection chamber is holding water or overflowing — a strong sign the problem is in the underground drain rather than the internal pipework.
Lifting the nearest inspection chamber cover, if you can do so safely, is genuinely informative. If the chamber is full of standing water, the blockage is downstream of it, toward the public sewer, and is a drainage job. If the chamber is empty but a fixture upstream is blocked, the problem is in the internal or branch pipework, where a plumber is the right call. Never enter a chamber or reach into one, and replace the cover securely afterwards, but a simple look tells you and the tradesperson a great deal about where the trouble lies.
Knowing this also protects you from paying the wrong trade twice. Calling a plumber for a problem that is plainly in the underground drain, or a drainage firm for a simple basin trap, can mean a wasted visit and a second call-out. Many firms cover both plumbing and drainage, but even then, describing the symptoms accurately means they send a van equipped for the actual job — rods, a jetter and a camera for an underground blockage, or hand tools for an internal one.
Frequently asked questions
Is a drainage company more expensive than a plumber?
For a single internal blockage, usually yes, because drainage firms carry jetting and survey equipment that a quick sink clearance does not need. But for underground or recurring blockages a drainage company is more cost-effective overall, because it fixes the cause rather than repeatedly clearing a symptom.
Can a normal plumber clear an outside drain?
Some can, with rods, but most plumbers are not equipped with high-pressure jetting, CCTV cameras or root cutters. For a blocked manhole, a recurring outside-drain problem or anything needing a survey, a specialist drainage company has the right kit and is more likely to clear and diagnose it in one visit.
Who pays if the blocked drain is outside my property?
Often the water and sewerage company. Blockages in the lateral drain beyond your boundary or in a shared sewer are usually their responsibility and may be cleared free of charge. Check who is responsible before paying a private firm for work outside your property line.
Sources & further reading
Figures on this page are typical UK ranges drawn from published cost guides and are intended as guidance, not a quotation.