Who Pays for a Blocked Drain?

Written by the Farnborough Contracting Services team.
over 20 years on the drains and ground of north Hampshire and west Surrey.

This is the first thing worth establishing, before you ring anybody, because it decides whether the job costs you a few hundred pounds or nothing at all. A lot of drainage firms will not raise it. We would rather you knew.

The short version

Pipes inside your boundary that serve only your property are yours. The pipe running from your boundary to the sewer, and the sewer itself, belong to your water company, and they clear blockages in their own pipes free of charge. If your blockage is out at the boundary or beyond, ring them first, not us.

The three kinds of pipe, and why the words matter

Everyone calls all of it “the drains”, but there are three distinct things and they have three different owners.

What it is	Where it runs	Whose it is
A drain	Inside your boundary, taking waste from your building and anything belonging to it, such as a garage	Yours
A lateral drain	From your boundary to the sewer, usually under the pavement or road	Your water company
A public sewer	Collecting from several properties, normally under the road	Your water company

Citizens Advice puts it the same way: a drain takes water and waste from a building and other buildings belonging with it; a lateral drain is a length of pipe carrying wastewater away from your property to a sewer, usually located outside your property boundary; and a public sewer collects wastewater from several buildings' drains and is maintained by the water company.

What changed in 2011, and why it matters more than people realise

This is the part that catches people out, including some contractors. On 1 October 2011, private sewers and lateral drains that were connected to the public sewerage system transferred to the water and sewerage companies. Pipes that used to be a homeowner's problem, and shared runs that used to be a row between neighbours, became the water company's responsibility overnight.

Two details make a practical difference. First, the transfer happened regardless of condition. A pipe did not have to be in good order to transfer, so the fact that your shared run is in a poor state does not mean it stayed private. Second, private pumping stations followed later, on a separate timetable, transferring by October 2016.

What did not transfer:

pipes inside your boundary serving only your own property
wholly private systems that do not drain to the public sewerage system, so cesspools, septic tanks and soakaway drainage
surface water sewers draining to a soakaway or a watercourse rather than a public sewer
railway sewers, and sewers on Crown land unless the owner opted in

There is a further wrinkle worth knowing if you are trying to establish what you own. When the transfer happened, notices went out to owners without plans attached, because there was no comprehensive mapping of private sewers and lateral drains. Your water company will give you a sewer map on request, and it is required to, but the map may simply not show a pipe that transferred. That is why locating a run with a camera and a sonde is often the only way to settle an argument about it.

Working out which one you have, without paying anyone

You can usually get there yourself with a cover key and ten minutes.

Find out what is affected. One sink or one toilet, and nothing else, is almost always a blockage in that fitting's own pipework, inside your property. Every waste fitting in the house backing up at once points to the main run further downstream.
Lift the covers, starting closest to the house. An empty chamber means the blockage is upstream of it, towards the house. A chamber standing full means the blockage is downstream of it, away from the house.
Keep going towards the boundary. Work outwards chamber by chamber. The last chamber that is empty and the first one that is full tell you which length the blockage is in.
If the full one is the last chamber before the boundary, or if the pavement chamber outside your gate is surcharged, you are almost certainly looking at a lateral drain or the sewer. That is your water company's, and free.
If neighbours have the same problem at the same time, that is a strong sign it is a shared run or the public sewer rather than your own pipework.

Ring your water company first if any of these are true

The chamber at your boundary or in the pavement is full; sewage is coming up outside rather than inside; more than one property is affected at once; or you have no idea and there is a chamber in the road. They will attend, and if it turns out to be your pipework they will tell you, and you have lost nothing but the wait.

Shared drains between neighbours

Terraced and semi-detached streets across Farnborough, Aldershot and Farnham are full of runs that serve several houses. Where such a run is genuinely still private, everyone it serves is jointly responsible for the cost of maintaining it, which in practice means agreeing a split before the work starts rather than after.

Before you get into that conversation, check with your water company whether the run transferred in 2011. A lot of shared drainage did. It is a short phone call and it can turn a four-way argument about a five hundred pound bill into a free visit from the sewerage undertaker.

If a drain is being so badly neglected that it is a nuisance or a health risk, your local authority's environmental health team has powers to require it to be put right. That is a last resort, but it exists.

What about septic tanks and treatment plants?

Entirely yours. Private drainage that does not connect to the public sewerage system did not transfer in 2011 and never will. If you are out in the villages around Alton, Farnham or Bentley, that probably means your whole system, from the house to the drainage field, is your responsibility to maintain, empty and eventually upgrade.

So when should you ring us?

When the blockage is inside your boundary and serves only you, which is most kitchen and bathroom blockages, most gully and manhole blockages close to the house, and anything where the camera shows a defect in your own pipework. Also when you want to know which of these you have and nobody will give you a straight answer.

We will tell you if it is not ours to fix. It costs us a call-out we were not going to be paid for either way, and it is the reason people ring us again.

Questions people ask

Who is responsible for a blocked drain in the UK?

You are responsible for the drains inside your property boundary that serve only your property. Your water company is responsible for the lateral drain, which runs from your boundary to the public sewer, and for the public sewer itself. Water companies clear blockages in their own pipes free of charge.

Do water companies clear blocked drains for free?

Yes, where the blockage is in a lateral drain or a public sewer, which they own and maintain. They will not clear a blockage inside your boundary that serves only your property.

What changed in 2011?

On 1 October 2011 private sewers and lateral drains that were connected to the public sewerage system transferred to the water and sewerage companies, regardless of their condition. Pipes within a property's boundary serving only that property did not transfer, and neither did septic tanks, cesspools or soakaway drainage.

Who pays if a drain is shared with neighbours?

If it is a private shared drain that did not transfer, all the owners it serves are jointly responsible for the cost of maintaining it. Many shared runs did transfer in 2011, so check with your water company before agreeing to split a bill.

Where this comes from

The rules, fees and figures on this page are taken from the sources below. Fees change, so check the current figure before you send anyone money.

This is general information about how the rules work, not advice on your particular property. If something here matters to a purchase or a dispute, get it checked on your own facts.

Is that blocked drain yours, your neighbours' or the water company's?