Where our water comes from

The L'Aube Hill water treatment plant provides the water supply for Akaroa and Takamatua.

Water for the Akaroa water supply scheme is taken from four streams (Aylmers, Grehan, Balguerie and Takamatua) and two wells, one at Settlers Hill Road (41 metres deep) and one at Aylmers Valley (138 metres deep).

The treatment process includes coagulation, flocculation, membrane filtration, chlorination and pH correction. The new L'Aube Hill treatment plant replaces three treatment plants, which were at L'Aube Hill, Aylmers Valley and Takamatua.

New pipelines were constructed to connect Takamatua to the Akaroa system, to bring untreated water from Takamatua Stream to the treatment plant, and to pipe treated water to Takamatua.  A new treated water reservoir was built on Old Coach Road at the highest point of the pipeline to provide storage for Takamatua. 

There are two other main treated water reservoirs, one at the treatment plant site on L'Aube Hill and the other at the former treatment plant site at Aylmers Valley.  There are also four smaller reservoirs.  As well as storing treated water, these reservoirs supply pressure for the network and most properties in Akaroa are supplied by gravity from these reservoirs.  In addition, there are four small pump stations to provide water for properties higher up the hill.

The Akaroa water supply scheme provides water to more than 1000 properties in Akaroa and approximately 130 properties in Takamatua.

Water for the Birdlings Flat water supply is sourced from a well located on Jones Road and is pumped through a pipeline to the treatment plant, which is located between Baileys Road and Poranui Beach Road.

Untreated water from the well is stored in above-ground tanks and is disinfected with UV light and dosed with chlorine using a temporary chlorination unit. The treated water is then pumped into the reticulation network.

The Birdlings Flat water supply is a restricted water supply. Each property is required to have a private storage tank and can receive up to 1,000 litres of water per day. There are currently 200 connections in the Birdlings Flat supply.

An upgrade project is currently underway to install cartridge filtration and a permanent chlorination system at the treatment plant. This will make the plant compliant with the Drinking Water Quality Assurance Rules.

In addition, a treated water reservoir will be installed at the treatment plant to provide additional resilience to the supply in the event of a power outage. All works will be completed by the end of 2025.

The Council has a consent from the regional council, Environment Canterbury, to take water from wells within the city, sunk down into the aquifers. There are 53 locations around the city where water is pumped into the pipe network. At each of these extraction sites there is at least one, and sometimes up to six, wells. These wells are typically 200mm and 300mm in diameter and are drilled down to depths ranging from 22–220 metres.

There are five layers of confined aquifers, with about 25 per cent of Christchurch’s water supply being sourced from the shallowest aquifer.  A programme is underway in the northwest of the city to replace some shallow wells with deeper wells, and once this is complete only 15 per cent of the city's water will come from the shallowest aquifer.  The water in these confined aquifers is under pressure, giving rise to artesian wells that in some locations flow freely at the surface.  

In Christchurch, water is delivered into water mains by electrically driven pumps keeping the mains pressurised and charged. The pressure forces water out when you turn on a tap in your house.

Where reservoirs or large tanks are sited on hill areas, water pressure is maintained by continually supplying water to the level of the reservoir. In areas where there are no nearby hills to put tanks on, pumps are kept running to ensure a continuous water pressure 24 hours a day.

Although Christchurch appears flat, there is actually a significant difference in land elevation from the east to the west of the city. Up to five pressure zones are needed, depending on the height of residential development. In addition, there is also a small public water supply at Brooklands and Kainga.

The water supply network is controlled from a central control room. As the pressure in the system falls and rises around the district, pumps are switched on and off by a combination of automatic and manual controls.

Pipe network

A vast network of pipes cover all urban parts of the city. This underground infrastructure spans from Belfast in the north to the hill suburbs in the south, and from Templeton in the west to Taylors Mistake in the east.  More than 1,700 kilometres of main pipes are laid - enough pipes to run from Christchurch to Whangarei. The total length of underground pipework, including submains, is 3,300 kilometres.

This network of pipes ensures that when a section of pipe has to be isolated for replacement or repairs, the number of households affected by stopped water supply is minimal. The main distribution pipes are made from fibrolite, PVC, polyethylene and cast iron. The pipes distribute all of the water and provide water for Council-maintained fire hydrants on the main pipes.

Water for the Duvauchelle water supply is sourced from Pipers Stream. Surface water abstracted from the stream passes by gravity to the treatment plant located on Okains Bay Road. 

At the treatment plant, this water passes through a mixed media filter and cartridge filter before being disinfected with UV light and dosed with chlorine. Treated water then passes into the treated water reservoir where it flows by gravity into the township or is pumped up to the Ngaio Point subdivision. There are currently 272 connections in the Duvauchelle supply.

The current treatment plant is unable to effectively treat raw water with high levels of turbidity and organics. This is an issue during periods of high rainfall. When this occurs, the plant is unable to operate, and water is tankered in from another Council supply.

An upgrade project is currently underway to replace the current treatment plant with a membrane filtration plant. This new plant will be able to treat water with high turbidity and levels of organics. It is expected that this plant will be commissioned by the end of 2026.

Water for the Little River water supply comes from two sources.

Surface water is abstracted from Police Creek, where it passes through a settlement tank before flowing by gravity down to the treatment plant. It is then treated by slow sand filtration and UV disinfection before being dosed with chlorine using a temporary chlorination unit and passing into the treated water reservoir.

During periods of heavy rain, the turbidity of the surface water abstracted from Police Creek can rise above the level that the sand filters can treat. At these times, groundwater is sourced from a 115-meter-deep well located at the bottom of Council Hill Road.

This water is then pumped up to the treatment plant where it is treated by UV disinfection before being dosed by chlorine using a temporary chlorination unit and passing into the treated water reservoir.

Water then flows out of the treated water reservoir by gravity into the reticulation network. There is a booster pump station located at the bottom of Council Hill Road that pumps water out to the Cooptown settlement.

The Little River water supply is a restricted water supply. Each property is required to have a private storage tank and can receive up to 1,000 litres of water per day. There are currently 94 connections in the Little River supply.

A series of upgrade projects are currently underway at the treatment plant to make it compliant with the requirements of the Drinking Water Quality Assurance Rules.

These projects include installing a permanent chlorine dosing system, the addition of continuous monitoring equipment for the UV treatment system, and alterations to the pipework in the treated water reservoir. The sand in the slow sand filters is also due for replacement. All works will be completed by the end of 2025.

Water for the Pigeon Bay supply is sourced from a spring above Dick Stream and passes through four settlement tanks before flowing by gravity to the treatment plant on Pigeon Bay Road.

At the treatment plant, the raw water passes through a cartridge filter before being disinfected with UV light and dosed with chlorine using a temporary chlorination unit. It then enters the reticulation network. Treated water is stored in three reservoirs.

The Pigeon Bay water supply is a restricted water supply. Each property is required to have a private storage tank and can receive up to 1,000 litres of water per day. There are currently 17 connections in the Pigeon Bay supply. 

An upgrade project is currently underway which will install a permanent chlorination system at the Pigeon Bay treatment plant. This will make the plant compliant with the Drinking Water Quality Assurance Rules. This will be completed by the end of 2025.

Water for the Wainui water supply is sourced from a 92-metre deep well located on Wainui Valley Road. Water pumped from the well is chlorinated using a temporary chlorination unit at the treatment plant before entering the reticulation network. Treated water is stored at two treated water reservoir sites.

The Wainui water supply is a restricted water supply. Each property is required to have a private storage tank and can receive up to 1,000 litres of water per day. There are currently 210 connections in the Wainui supply. 

An upgrade project is currently underway which will install cartridge filtration, UV Treatment, and a permanent chlorination system at the treatment plant. This will make the plant compliant with the Drinking Water Quality Assurance Rules.

In addition, a generator will be installed at the treatment plant to provide additional resilience to the supply in the event of a power outage. All works will be completed by the end of 2025.