Current Alerts and Notices (View all)

Road conditions(2) Swimming pools notice(1)

Dunedin City Council – Kaunihera-a-rohe o Otepoti
Green pattern.

Dunedin water supply system

The system includes 21,000 hectares of water catchment, 6 treatment stations, 35 pumping stations, 57 reservoirs (raw and treated water) and 1450 km of pipes.

Water supply infrastructure diagram

Where does our water come from?

We hold permits to take water from various rivers around Dunedin and manage many of our catchments to improve the quality and quantity of our water supply. The best catchment land is covered in natural bush or tussock to reduce the impact from stock, pests and other land use. Tussock plants collect  and retain water, so having them in a catchment increases the water yield.

Dunedin’s water supply is sourced mainly from Deep Creek and Deep Stream, tributaries of the Taieri River. The Silverstream, Water of Leith catchment, Sawyers Bay and Port Chalmers catchments, Waikouaiti River and Waipori River supply outlying areas and supplement Dunedin’s supply when needed.

How do we get water to the treatment plants?

A 174km network of pipes carries raw water to treatment plants or to reservoirs for storage.

Storing raw water in reservoirs helps make sure we have enough water when there has been little or no rain in the catchments. Seven dams at Mount Grand, Southern, Cedar Farm, Rossville, Ross Creek, Sullivans and West Taieri hold up to 942,000m³ of raw water –  enough to supply the city for  21 days at average demand.

The Deep Stream and Deep Creek pipelines, 58km and 64km respectively, use gravity to take water to the Mount Grand reservoir.

The Silverstream intakes feed the Southern reservoir via the Silverstream pumping station and pipeline. The pipeline from the infiltration gallery in the sediments next to the Taieri at Outram can also supply the Southern reservoir.

Water for the Port Chalmers, Waikouaiti, Outram and West Taieri water treatment plants is piped a short distance from source.

How do we treat water?

The two largest water treatment plants, Mount Grand and Southern, supply most Dunedin customers. The Port Chalmers water treatment plant supplements the water supply during the cruise ship season (October to April). Waikouaiti, Outram and West Taieri also have small treatment plants.

At the plants, water is treated to meet national drinking water standards. For more information on our water treatment methods page in the related information section.

How do we get treated water to you?

Treated water is carried from the plants to reservoirs around the city via a network of large mains, pumps and valves to maintain or reduce pressure.

From the reservoirs, 726km of pipes bring water to properties, with DCC responsibility ending at the ‘point of supply’ which is either a toby (small cast-iron round lid) or a manifold unit (blue plastic or metal lid) in the footpath.

What should I do to maintain my water quality?

Water can dissolve heavy metals from plumbing fittings, including lead, nickel, cadmium, copper and antimony. It’s a good idea to flush your taps if they haven’t been used for six hours or longer. This reduces the chance of increased concentrations of leached metals in the water.

Soft, slightly acidic water dissolve metals most readily. To reduce this problem, the final step at Mount Grand and Southern water treatment plants is to correct the pH to reduce acidity and harden the water. Even so, water that has been standing in plumbing fittings for a long time, such as overnight,  can leach metals. To make sure your water is safe, flush about half a litre through your taps before drinking, cooking or brushing your teeth.

Still didn't find what you were looking for?