The Council has obligations under specific acts and bylaws to safeguard the health of the community and the environment. The main regulations governing the collection, treatment, and discharge of wastewater are the Resource Management Act 1991, the Local Government Act 1974, the Building Act 1991 and the Council's own Trade Wastes Bylaw. Monitoring of levels of certain chemicals takes place. In some instances particular substances are either prohibited, e.g. asbestos or organochlorine pesticides, or are allowed into the sewer only in limited quantities, as is the case with chromium, nickel and cadmium.
Because of the need to provide for such a valuable asset, the Christchurch City Council has an asset management plan in place to manage the wastewater pipeline assets. The plan provides a strategy to meet the demands of expected city growth well into the 21st century to maintain the pipe assets and to upgrade the level of service where appropriate.
One advantage that the Christchurch sewage system has is the high quality of its pipe infrastructure, due to the high level of asset investment in past years. Without such a high standard of early piping, the city may well have run into difficulties as the city has a high water table and draws its drinking water from underground aquifers. Most pipes laid in the city are below groundwater and pipe imperfections could cause groundwater infiltration as well as overflows.
Existing pipelines under the city are a mixture of old brick, ceramic, cast iron, newer concrete, and plastic. For optimum performance the pipes need to be regularly maintained and upgraded where necessary. The pipes have an average economic life of at least 90 years, with older pipes being renewed as needed. Until recently, the only way of knowing the condition of underground pipes was when they blocked or failed, leaving a depression in the road. With the introduction of closed circuit television monitoring, the condition of the pipes can be regularly checked to prioritise their renewal.
Property owner's responsibility
All structural damage to sewer laterals or pipes inside the property boundary is the owner's responsibility.
The owner is also responsible for all blockages to sewer laterals caused by inappropriate items being flushed down the sewer system up to the council sewer main in the road. It also includes tree roots.
If a drainlayer is sure that the cause of blockage is a Council responsibility, contact the Customer Contact Centre, phone (03) 941 8830 .
The Council's responsibility
Structural damage such as cracks or breaks in the sewer system in the footpath or road and on Council-owned properties are repaired and maintained by the Council.
Pipelines on private properties are often protected by way of easement in favour of the Council. This means that Council has legal access to the pipelines.