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Sewerage services

Northern Ireland Water aims to provide a reliable and efficient service for collecting, treating and disposing of wastewater, and to ensure that any problems that occur with sewerage system are dealt with efficiently and without unnecessary delay.

The sewerage system

The system of pipes used to collect and carry rain, waste water and trade waste away for treatment and disposal is called the sewerage or the waste water system.

There are three types of sewerage systems:

  • foul sewers – carry waste water, for example waste from toilets and from trade premises to our wastewater treatment works
  • surface water, or storm sewers – carry rainwater from roofs, paved areas, pavements and roads and generally flow into streams, rivers or watercourses
  • combined sewers – this is a single pipe system which carries both wastewater and surface water to wastewater treatment works. These are often found in older town centre systems and are no longer designed or constructed

It is an offence to discharge foul sewage to a sewer designated for surface water or surface water into a sewer designated for foul sewage.

All new sewerage systems should be designed on separate foul and surface water (storm sewers) systems.

Sewage treatment

Sewers carry both domestic and industrial waste water to wastewater treatment works, where it is treated and safely disposed of in accordance with statutory requirements. After treatment, the cleaned water goes to a nearby watercourse or the sea and must comply with statutory conditions set by the Environment and Heritage Service (EHS).

The sewage sludge which is produced as a by-product of the sewage treatment process is further treated and disposed off through incineration and landfill, again in accordance with statutory requirements and approval by EHS. If you have a problem you should contact NI Water:

You can use the link below to report a leak online:

Responsibility for sewerage pipes

The pipework which makes up the sewerage system can be categorised in three ways:

  • public sewers – Northern Ireland Water owns, operates and is responsible for maintaining a network of over 13,000 kilometres of public sewers which are designed to take away waste and rain water to our wastewater treatment works
  • drains - a drain is a pipe which carries waste water (from sinks, baths and toilets) and trade waste from one property to a sewer. Responsibility for the drain within the boundary of the property lies with the owner of the property.
  • private sewers - a private sewer is a pipe which collects and carriers waste and waste water from several properties. A private sewer may connect to a public sewer or private wastewater treatment works. Responsibility for a private sewer lies jointly with the owners of the properties which it serves

Access to sewerage pipework

In most cases sewers are situated in roads or public open places, however, they may run through private gardens, in which case NI Water has a right of access for maintenance.

Work on public roads

Many watermains and sewers are laid in public roads and footpaths and consequently there will be occasions when there is a need to carry out maintenance work on them.

There are other occasions when NI Water will need to carry out work on a larger scale to either extend or replace existing watermains or sewers and where they carry out work of this nature they undertake to:

  • carry out the work in a manner which causes the minimum disruption or inconvenience to both road users and residents
  • ensure public safety at all times
  • reinstate the road or footpath to the standard required by Roads Service

Work on private land

There will be occasions when NI Water has to enter your property to lay new services, maintain existing services or inspect your water or sewerage system. On those occasions and in cases of emergency they will make every effort to notify you before entering your land. However, if there is an emergency, they have power of entry to your land without notice but will make every effort to consult with you before doing so.

In either event they will endeavour to cause as little inconvenience and damage as possible and on completion of any work carried out, will make good to a reasonable standard.

Getting connected to the public water supply or sewerage system

NI Water is responsible for the provision of services associated with all aspects of development including first time service appraisal, diversions, extensions to the watermain distribution system and sewer network, watermains in new development and adoption of sewerage systems.

Customer Care Register (including Critical Care)

NI Water provides essential services for all customers throughout Northern Ireland. for older consumers, those who have a serious medical condition or need extra help for any other reason.

You need to join the Customer Care Register to get the extra free services you or anyone in your household would like to receive:

More useful links