Managing Wastewater

Once water has been used in your home, school or business, the wastewater is collected, treated and returned safely to the environment. Council provides connections to reticulated wastewater in most urban areas of Central Otago. Privately owned septic tanks are used in townships and areas without reticulated schemes.


What is Wastewater?

Wastewater is the water that drains into a sewer pipe, each time you flush the toilet, pull the plug from a sink, have a shower or use water on your property. Wastewater is also known as ‘sewage’. Wastewater contains bacteria and waste materials, which are treated or removed to protect public health and the environment.
Most wastewater comes from showers, baths and washing machines. Wastewater is 99 per cent water. The other 1 per cent includes organic matter such as human waste, food scraps, fats, oil and grease, and debris such as sand, grit and plastic. Wastewater can also contain household chemicals, paint and pharmaceuticals, which can be harmful to our health and to waterways. 


Where does Wastewater go?

Reticulated wastewater goes to a wastewater treatment plant. These vary from complex sludge treatment and removal systems to simple, but equally effective, oxidation ponds. Sludge from septic tanks is taken to a wastewater treatment plant.

At the plant, nutrient rich organic solid residues known as bio-solids are removed and the wastewater treated to a standard that protects public health, the local environment and waterways. The treatment standards are set by the Otago Regional Council and are stated in the Resource Consent Council holds to dispose of wastewater. Biosolids from Central Otago wastewater treatment plants are currently trucked to the Victoria Flats Landfill near Queenstown. New options for the treatment and removal of bio-solids are being investigated. 


Who pays to treat Wastewater?

Wastewater treatment is funded by ratepayers connected to reticulated supplies. An annual uniform charge on the rates account funds the maintenance and development of wastewater storage, pipes, pumps, and treatment plant and processes.


Problems with your Wastewater System?

If you have a blockage in your wastewater system you need to call your plumber.

If the blockage is in your private plumbing, your plumber will need to fix it. If your plumber decides the blockage may be Council’s responsibility, your plumber must contact Council to determine who is responsible for repairing the problem. If the blockage is a Council problem it will be fixed at Council’s cost.

A blockage in the lateral that services your property, whether it is on your property or crossing another property is usually your responsibility to correct. If the lateral is blocked because of a pipe failure outside your property boundary, Council will usually replace the pipe. If the problem is caused by tree roots, the problem is the property owners’ responsibility. For more on this issue see the advice in this Consumer website article.


Odour Complaints

Council takes all complaints about odour from the wastewater system seriously. Council will act promptly to address the problem. Odour issues should be reported as soon as possible so that these can be properly investigated.


Emptying Septic Tanks

Maintenance of septic tanks is the responsibility of the property owner. Three private operators currently hold licenses with the Central Otago District Council to dump septage (waste content from a septic tank) and wastewater. 

  • S J Allen 027 435 6954
  • Wastech  03 445 8082


      Septage may only be disposed of at the Cromwell and Ranfurly Wastewater Treatment Plants. A disposal charge applies per each 1000 litres of septage pumped into the wastewater system. 


      Managing & Monitoring Wastewater

      Council’s approach to managing wastewater is detailed in the current Annual Plan and Long Term Plan


      More Reading

      The Story of Your Septic Tank System (NZ Water & Wastes Association)

      Page reviewed: 21 Jun 2017 2:52pm