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• Drainage - help and advice
• When is a Main Sewer not a Public Sewer

What is the difference between a drain and a sewer?

Drains

Drains take effluent from a single curtilage.

Curtilage

The legal definition of a curtilage is quite complex, but is usually accepted as meaning a boundary around land and buildings/structures that were built or occupied for a common purpose. This is usually the same as the property boundary. However, sometimes a curtilage will contain more than one dwelling. Examples of this would include:

• A property that was built as a single house but was then converted into flats (as in Figure 1).
• A group of cottages built and used for worker accommodation.

Sewers

Sewers take effluent from more than one curtilage.

Who is responsible for clearance, maintenance, and repair of drainage systems?

Public sewers

These are usually the main sewers found running beneath roads or pavements, and are generally larger in diameter (at least 6”) than private sewers or drains. Responsibility for public sewers lies with the Sewerage Undertakers and therefore you should contact them if you notice a problem with a public sewer, for example, sewage overflowing from a manhole in the road.

Sewerage Undertakers:

Anglian Water (covers most of Central Bedfordshire) - Tel: 0800 145 145

Thames Water (covers the southern part of Central Bedfordshire) - Tel: 0845 9200 800

Exceptions - Please use the following link for an explanation of when the above definition of a public sewer is not the case, and for information on getting existing sewers adopted. When is a Main Sewer not a Public Sewer?

Section 24 sewers

Some sewers which at first glance look like they may be private sewers due to their size and location (under gardens etc), may in fact be known as "Section 24 sewers". Section 24 sewers are sewers that were constructed pre 1937 and were known to connect to a public sewer at this time. Section 24 sewers are in fact public sewers and are therefore the responsibility of the Sewerage Undertakers.

Private sewers

Private sewers connect drains to public sewers. Responsibility for the removal of blockages and repair of defects in private sewers (and drains) lies with the owners or occupiers of those properties served by the affected pipework (i.e. those upstream of the blockage or defect).

How do blockages occur?

Blockages can occur for a number of reasons, including:

• Inappropriate items such as nappies, sanitary products, baby wipes, incontinence products etc. being flushed down toilets.

• Fat and grease from cooking which solidifies once it has been poured down the sink leaving thick coats around the inner surface of pipework, thereby reducing the bore and thus the effectiveness of the drains and sewers.

• Tree and shrub roots penetrating drains and sewers.

• Structural defects such as fractured pipework, miss-aligned pipework joints, undulating pipework, insufficient gradient of the pipework, or pitch-fibre pipework that has become squashed over time.

What do I do if a drain or sewer I am responsible for blocks?

When blockages in drains/private sewers occur it is up to those upstream to get together and arrange for the blockage to be removed. If someone has a set of drainage rods then this will usually do the trick, however, if rods are not available or the blockage is so severe that high pressure water jetting is required, residents will need to contact a suitable contractor from the phone book and split the bill.

What action can the Council take to ensure blockages in private sewers and drains are cleared?

In some situations such as where neighbours do not get on with each other, individuals are reluctant to organise clearance in case other residents do not contribute to the cost of the work. If this occurs the Council will get involved. An officer will visit to establish what the problem is and who is responsible. They will then be able to serve notice (Section 35 of the Local Government Miscellaneous Provisions Act 1976 for sewers, or Section 17 of the Public Health Act 1961 for drains) on those residents upstream of the blockage requiring them to remove the blockage within a minimum period of 48 hours. If the residents fail to comply with this notice then we will arrange for contractors to carry out the necessary work, and will then recover the cost plus a 20% administration fee from the residents. This is the only way we can ensure that everyone pays their fair share.

If there are Housing Association properties upstream of the blockage will the Housing Association arrange clearance?

The drain/sewer I am responsible for regularly blocks does this mean that there is a defect?

Regular blockages in the same place may indicate that a structural defect exists at that point. In order to determine the exact position and nature of the defect it is often necessary to carry out a CCTV survey of the drain/sewer.

Insurance policies

It may be a good idea to contact your insurers at this point to check whether any buildings policy that you may have would cover repairs to defective drains or sewers, as sometimes insurers will carry out the CCTV survey and then arrange for any defects found to be repaired. Whether your policy covers the repair of the drain or sewer depends on where the defect is located and how your policy is worded.

For instance, if the defect lies outside the boundary of your property but you are responsible for it by virtue of being upstream then a policy which states that it covers "pipework within the boundary of your property" will probably not cover the necessary repairs, whilst a policy which states that it covers "all pipework which you are legally responsible for" probably will, unless the nature of the defect means that it is not covered.

The nature of the defect will have a bearing on whether the repairs are covered by a policy, as if the insurance relates to accidental damage it may not cover repairs to defects which exist due to the system being initially constructed incorrectly (e.g. insufficient gradient of the pipework).

What action can the Council take to ensure that defective private sewers and drains are repaired/replaced?

We can serve notices (Building Act 1984 - S.59) on the owners of those properties upstream of a defect requiring remedial works to be carried out if the homeowners are unable to arrange (with or without their insurers help) it between themselves. The minimum timescale that we can specify on these notices is 21 days although more time may be given if the officer feels that it is appropriate. If the notices are not complied within the specified timescales then we will arrange for contractors to carry out the works in default and recover the cost plus a 20% administration fee from the homeowners.

Arranging a CCTV survey (including a video) of the affected section of sewer may be helpful as you could then forward a copy to us so that we can identify the nature and location of the defect, and specify the most appropriate remedial works in the aforementioned notices.

What can the Council do with regards to overflowing cesspits and septic tanks?

We can serve notice under Section 50 of the Public Health Act 1936 on the occupiers of premises that drain into cesspits and septic tanks if they are overflowing. If the notices are not complied with within the specified timescales then we will arrange for contractors to carry out the works in default and recover the cost plus a 20% administration fee from the homeowners.

Do you have any advice for septic tank users?

Do

• Put all the waste water (except rainwater from roofs etc) into the system. Any of these waters may contain disease-causing microbes or environmental pollutants.
• Use bleaches, disinfectants, sterilisers or germicides sparingly, as they could kill the bacteria in your septic tank which help to digest the waste. Domestic cleaners are biodegradable and should not harm the tank in normal use.
• Inspect the system at least once a month, including water levels in the distribution chamber and the drainage field.
• Check the tank regularly and desludge/empty as required. The frequency of this will depend upon the capacity of the tank and the number of households deriving benefit from the system.
• Act immediately if you find a blockage or any sign of pollution. Do not allow effluent to collect on the ground surface.
• Keep records of inspections (e.g. water levels), desludging activities and any maintenance undertaken.
• Ensure that all covers can be secured, but removed when necessary.
• Ensure that air vents are not blocked.
• Ensure that the drainage field is protected. Do not dig in it, drive over it, plant anything over or near except grass, or cover it with a hard surface such as concrete or asphalt.

Don't

• Use your toilet or kitchen sink as a rubbish bin. Use compost bins where possible.
• Dispose of rags, nappies, sanitary items, plastic or other large solids. They will cause blockage and backing up.
• Pour paints, solvents, hazardous chemicals, pesticides, fats, oils or heavy grease and sump oil down the drain. These should be kept in their original containers and recycled. Some of these substances may be taken to the Household Waste Recycling Centres in Central Bedfordshire.
• Empty chemical toilets into drains or septic tanks.
• Use caustic solutions to unblock drains. Use boiling water or drain rods instead.
• Allow rainwater to drain into the tank or surface water to flood the drainage field. Flooding will sweep solids through the tank and inhibit treatment in the drainage field.
• Ever enter a septic tank. Toxic gases are produced by the natural treatment processes.

Indicators of problems with your system:

• Slowly draining sinks, toilets, baths etc.
• Tank covers lifted by overflowing solids.
• Backing up of sewage at the inlet.
• Surface flooding downstream of the tank.
• Nettles and vigorous plant growth downstream.
• Ground movement near the tank or drainage field.
• Polluted water in a ditch or watercourse.
• A smell of sewage in the area.