Sewage and drainage

Last Updated: 3 April 2024

Drainage is the process that allows water and waste water to be carried away from one area to another by either natural or man made channels. Different responsibilities apply to foul drainage depending on if your property has mains drainage or a septic tank.

Road drainage

The drainage of adopted roads (public highways) is the responsibility of the highways team. 

Whilst the gullies on public highways are cleaned out regularly, if you notice that they become blocked they may cause flooding and you should report this to our Highways Team.

Watercourse pollution

If you suspect that a watercourse has become polluted you should report this to the Environment Agency as soon as possible. They can be contacted on 0800 807 060.

Mains drainage

If your property is connected to a mains sewer it will initially drain through a private drain. The private drain will normally remain your responsibility until your property boundary or until someone else’s drain connects into it.

United Utilities are responsible for the mains sewerage network in this area, that is public drains serving more than one property or outside your property boundary. 

United Utilities: Guidance about your pipes
United Utilities: Sewers and drains explained

Septic tanks

In rural areas without mains sewers most properties drain to septic tanks.

The term 'septic tank' is used to describe a number of different types of sewerage treatment system, but all of these require regular maintenance.

How to find out if you have a septic tank

In most situations the title deeds for a property will indicate whether the property drains to a septic tank. Your neighbours may also have knowledge of how your own property is drained.

If you live in a rural area and do not pay Sewerage Charges as part of your Water Rates you will almost certainly drain to a septic tank.

You can also contact the Water Company, United Utilities, who hold records of all main sewers in the area. Telephone: 0845 602 0406.

Responsibilities of the property owners 

If your property drains to a septic tank, you are responsible for the tank, together with any soakaway or outlet from the tank.

In law, the responsibility for emptying and maintaining septic tanks is divided equally between the properties connected to them, unless legal documentation exists to prove otherwise.

The ownership of land does not alter the responsibility for septic tanks, or their outlets, and many home owners/occupiers will be responsible for septic tanks that lie on, or drain under, a neighbours land.

New rules came into force on 1 January 2015 for septic tanks and sewage treatment plants and people have until 1 January 2020 to comply. The rules are known as the General Binding Rules.

The rules apply to existing and new treatment systems and people must use the correct treatment system. There are two basic types of discharge: discharges to surface water and discharges to ground. There are also cesspools which are in effect just storage tanks that are emptied when full.

All treatment systems including drainage fields must meet the correct British Standard unless they were installed before 1983 as the Standards didn’t exist then, however treatment systems must still comply with the general binding rules and be maintained to ensure they continue to comply.

Discharge to surface water

You must use a small sewage treatment plant to treat the sewage if you’re discharging to a surface water such as a river or stream up to a maximum of 5 cubic metres per day. A small sewage treatment plant (also known as a package treatment plant) uses electricity and mechanical parts to treat the liquid so it’s clean enough to go into a river or stream.

Discharges from traditional septic tanks (no electricity and mechanical parts) directly to a surface water are not allowed under the general binding rules from 1 January 2020.

If you have a septic tank that discharges directly to a surface water you will need to replace or upgrade your treatment system by 1 January 2020.

Where you can’t comply for any reason you can apply to the EA for a permit to allow an existing or new discharge to a surface water from a septic tank. However permits may only be granted in exceptional circumstances.

Discharges to ground

You must use a septic tank or small sewage treatment plant to treat the sewage and then discharge the effluent (treated liquid) to ground via a drainage field up to a maximum of 2 cubic metres per day. A septic tank is an underground tank where the solids sink to the bottom, forming a sludge, and the liquid flows out to a drainage field.

A drainage field typically is a series of pipes with holes laid in trenches and arranged so that the effluent can trickle through the ground for further treatment. You cannot use a soakaway (designed for draining rainwater), well or borehole for discharging effluent to ground. Instead you must either upgrade to a drainage field, small sewage treatment plant or apply to the EA for a permit.

Further guidance is available from GOV.UK: Septic tanks and treatment plants: permits and general binding rules.