Drainage and sewerage

The Council’s Drainage Division is responsible for two essential services, wastewater (including sewage) and stormwater. The Drainage Division maintains over 300km of sewerage pipes, 400km of stormwater pipes and treatment plants in Bluff, Omaui and Clifton.

The treatment section has  information on the Clifton wastewater treatment plan, the bio-solid project, the Bluff plant and Omaui treatment.

Related links:

Blocked drains

Blockages, odour, sewage and stormwater overflow can occur for a number of reasons: extreme weather, children putting sticks and other foreign matter down the toilet system, a missing grate, old or damaged pipes …
Note that sewage overflow is a potential health risk, especially if it enters the water supply, and therefore requires urgent attention.

The Council is responsible for the maintenance of stormwater and sewage pipes which lie beneath the roads and the property owner is responsible for the pipes, drains, ditches and culverts etc on their own property.

If you discover a blocked, damaged or overflowing drain in a public place contact the Council’s Drainage Division or you can email us using the Council’s Request For Service Form.

Property owners should contact a registered plumber if there is a blocked, damaged or overflowing drain on their property or property boundary. If the registered plumber believes that that this is a Council matter, then the plumber should contact the Council on your behalf.


The Council maintains the culverts under the roads and also the headwall structures (the entry and exit points of the culverts). Permission must be sought from the Council if you intend on piping a roadside culvert for property access – the Council can also provide you with information about pipe size, construction standards and location for road safety.

Roadside Ditches

Maintenance of roadside ditches is generally the responsibility of the adjacent landowner – this includes ditches on the landowner’s property and road frontage. In some areas of Makarewa, Myross Bush and Otatara the ratepayers pay a drainage rate and the Council, on the landowners behalf, maintains the ditches. Permission must be sought from the Council if you intend on piping a roadside ditch for property access.

Septic tanks

Property owners of homes not connected to a public drain are required to provide and maintain their own on-site, below ground level, wastewater/sewage treatment system. These systems – septic tanks – should be regularly maintained and cleaned by a registered septic tank cleaning contractor.

Building consent is required by the property owner before a septic tank can be installed. This is to ensure that the tank meets the standards for building, environment and public health and safety.

If your septic tank fails contact a septic tank cleaning contractor in the first instant. If your septic tank fails and also discharges sewage you are required to notify the Council’s Environmental Health Division.


Stormwater can be defined as the water run-off. The Council maintains more than 4,000km of stormwater pipes in the city area. Invercargill and Bluff have urban stormwater systems which lie beneath the roads. At Makarewa, Myross Bush and other parts of Otatara properties are served predominately by a system of ditches for stormwater.

When it is not possible for a property to be connected to a public drain to discharge stormwater, the property owner may apply to the Council for consent to install their own channel connections.

Trade waste

Trade waste is waste from commercial and industrial premises other than domestic sewage and wastewater. Guidelines for all new, existing and potential trade waste dischargers can be found in the Trade Waste Bylaw.

Trade Waste Bylaw
Trade and tankered waste fees

Application and consent
Contact or visit the Council for a trade waste discharge application. It is also important to discuss with Council whether your business requires a trade waste consent, and if so, what specific type. If your business has been approved and a trade waste consent issued, the Council will then visit and inspect your business premises annually to ensure that discharges comply with the conditions of the consent.