CCW is frequently contacted by consumers for advice and guidance on drains and sewers.

This fact sheet explains ownership, responsibility and liability for a number of issues commonly associated with the sewerage system.

What are drains and sewers, and who owns them?

Ownership depends on whether the pipe is a drain, a lateral drain or a sewer.


A drain is a pipe that carries foul sewerage and/or surface water away from a single property. It serves only that property and sits within the boundary of the property (known as ‘curtilage’ in the regulations).

The property owner is responsible for maintaining and repairing drains up to the boundary of their property. Some properties – like blocks of flats – have shared drains. Owners of these properties are jointly responsible for their drains.

Lateral Drains

Lateral drains eventually connect to the public sewer and serve just one property but lay outside the property boundary. Lateral drains may lie under private or public land, including highways.

As of 1 October 2011, sewerage companies became responsible for all lateral drains that existed at that time.

In England, anything built after October 2011 will need to be legally adopted by the sewerage company or it will be the responsibility of the owner until it meets the sewer.

In Wales, lateral drains will have been automatically adopted by the sewerage company as part of the different ‘secondary adoption legislation’ as long as the developer has followed the correct procedure.


A sewer carries waste water and serves two or more properties.

If a property shares a sewer pipe with adjacent properties, then responsibility for its maintenance falls to the sewerage company, even if it is within the boundary of the property (and as long as it was built before October 2011).

There are foul sewers, which carry only the waste water away from properties, or there are (usually older) properties that are served by combined sewers, which carry both waste water and surface water away.

In recent times, sewerage companies try to have separate surface water systems where possible. This is because surface water can add a lot of volume and pressure on sewerage systems when it rains and can cause sewers to overflow


What happens if your drains are blocked?

Customers might complain of their toilet backing up or if sinks or baths are draining slowly.

This may be due to a blockage. Blockages can occur for a number of reasons.

Common causes include a build-up of paper, face wipes or sanitary products, damage from tree roots, or the hardening of cooking fat or other foods poured down drains. Very occasionally, a drain or sewer can collapse.

If you are unsure about the location of the blockage, check if your neighbours are affected. If they are, it may indicate a problem further down the system. If you remain unsure about whose responsibility it is, contact your sewerage provider and keep a record of your contact. This will help you later if the company tells you the blockage is private and you later learn it was not.

Householders of properties built before 2011 are only responsible for drains that serve their property alone, and are within their boundary.

The sewerage company is responsible for the public sewerage system. So, if the blockage is in the lateral drain or the main sewer then the sewerage company will be responsible for clearing it.

What happens if the sewer overflows and floods your property, either internally or externally?

We know that sewer flooding can be one of the most distressing and unpleasant problems that customers can face.

If the problem is related to something in your private drain, you will need to hire a drainage contractor to clear this.

If you are unsure where the problem has occurred, always contact your sewerage provider in the first instance and keep a record of your contact.

If there is a problem with the public lateral drain or sewer, contact the sewerage provider straight away.

If sewage has entered your property from a public sewer, the company should send someone out to visit you as soon as possible. The time it takes for the company to respond may be affected by severe storms and how widespread the flooding is.

It is important to understand that if the flooding has been caused by the public sewer, the sewerage provider are responsible for fixing the problem but not necessarily responsible for any damage caused. This is because sewerage companies have no control over what is placed in the sewer and so the regulations state they are not responsible unless negligence can be proved.

Different companies offer different levels of service in flooding situations, including clean up assistance. Ask your company what specific help it can offer you. This should also be set out in its Code of Practice, which you can ask it to send you or look for on its website. To claim for damages to property or goods, you will need to contact your home insurer. If appropriate, they will make a claim on your behalf to the company.

Can you claim compensation if you are flooded?

There is a statutory Guaranteed Standards Scheme (GSS) that means your company must pay you compensation if your property is flooded inside or outside. In both instances, you must contact the company to claim this within three months of the incident. You can find a copy of the GSS guidance on Ofwat’s website (pdf).

For internal flooding, compensation is equal to refunding your yearly sewerage bill (with a minimum of £150 up to a maximum of £1,000) for each time flooding happens. For external flooding, compensation is equal to 50% of your sewerage charges (with a minimum of £75 up to a maximum of £500) for each occurrence, however, the regulations say you must have been ‘materially affected’. To decide if you have been ‘materially affected’, GSS guidance says companies must consider:

  • what parts of the land or property the effluent entered;
  • the duration of the flooding;
  • whether the flooding restricted access to the land or property;
  • whether the flooding restricted the use of the land or property; and
  • any other relevant considerations of which the company is aware.

The flooding must have been reported and witnessed at the time by the company so always contact it and report each flooding incident.

Reporting every incident also helps to identify if there are any underlying issues in the area that might need fixing or regular maintenance.

If the flooding was caused by exceptional weather, the company does not have to make any payment. It is important to understand that no company can reasonably build sewers that can cope with every eventuality. Under regulation, sewers should be able to cope with normal rainfall. Anything above a ‘1 in 30’ storm is classified as ‘exceptional weather’ under the GSS guidelines.[1] Your company will tell you if this is the case.

Sometimes a permanent fix to sewer flooding requires significant investment, such as when a sewer needs replacing. Sewerage companies will prioritise any investment based on the number of customers affected as well as the seriousness and frequency of any flooding. However, if a permanent solution cannot be quickly put in place, your company should be able to offer mitigation in the meantime.

[1] Classification by the Met Office. A “1 in 30 storm” means that the storm was of a strength likely to only occur once every 30 years.

Other Sewer Issues

Sewer Odours

CCW understands that persistent odours from sewers or pumping stations can affect those living or working nearby. We can help you bring your concerns about odours to your sewerage company if you have exhausted its complaints procedure yet have not had a satisfactory reply. CCW can help to ensure your company addresses your concerns and tries to find a long term solution if required.

If the odour is coming from sewers, the company may take preventative action, such as regularly flushing a section of sewer that is likely to block. It may also take action such as writing to all residents to inform them what they should or should not flush away in order to minimise the chance of blockages.

If the odour is coming from a pumping station, your company may need to fix a defect or add chemicals to minimise the odours.

It is always helpful to keep a diary of the dates and times you are experiencing any issue. It can often be worse in hot, dry weather where there is less surface water in the pipes, so waste is not being flushed through effectively enough.

You may also wish to contact your local Environmental Health Officer (EHO). The odour may be classed as a public health nuisance and the EHO does have powers to take action against the companies if they do nothing to resolve the matter.

Location of Sewers and/or Building over Sewers

All water and sewerage companies have a duty to maintain accurate maps of their network and assets.

However, many were networks were inherited from previous incumbents (local councils) or drawn up before there were accurate or digital records. Therefore, all maps carry a disclaimer that says further investigation is needed to be sure of precise locations.

In October 2011, sewerage companies were required to adopt private sewers. None of these laterals drains and sewers were on existing maps. There is no duty on companies to proactively map all these; however they should add them to their maps when they come across them.

Most companies will not allow people to build within three metres of a sewer. This is because they need access to them if anything goes wrong. Building over a sewer can also add a risk of collapse.

However, there are times when some companies may allow people to build near or over a sewer. This is at the sewerage company’s discretion. Where they do allow this, they usually require a customer to enter into a legally binding ‘Build over sewer agreement’. This is a process the customer has to pay for and ensures that if access is needed it must be granted.

If the company will not allow a build over, the customer may be given an option to request a sewer diversion. A customer can pay the company to divert the sewer to allow construction (this is something developers might choose to do).

Rat Infestation

It is an unfortunate and unpleasant fact of life that rats do sometimes live or travel through drains and sewers. Sewers are not sealed units, unlike water pipes, and can make a perfect habitat.

Customers experiencing issues with rats should contact their local Environmental Health Department. If the Environmental Health Department confirms that the sewer is causing the issue then contact your company, which should work with you and the local authority to resolve the problem. They may carry out CCTV surveillance to see if there are any significant gaps or defects that need to be fixed, or they may lay bait or install rat traps.