Why Christchurch Is Spending $2 Billion on Water Infrastructure
Water & Environment | By Harpreet Singh | 9 July 2025 | 13 min read
From earthquake-damaged pipes to estuary health and flood protection -- why water is the biggest item in Christchurch's budget, and what it means for your rates and your tap water.
Water Infrastructure Investment by Type (10-Year LTP)
| Name | Value |
|---|---|
| Pipe Renewals & Replacements | 950 $M |
| Wastewater Treatment | 420 $M |
| Stormwater & Flood Protection | 380 $M |
| Water Supply & Treatment Plants | 250 $M |
Christchurch Water Network at a Glance
| Name | Value |
|---|---|
| Water Mains | 1700 km |
| Wastewater Pipes | 1600 km |
| Stormwater Pipes | 915 km |
Environmental Water Quality Indicators
| Name | Value |
|---|---|
| Drinking Water Compliance | 100 % of target |
| Avon/Otakaro River Health | 55 % of target |
| Heathcote/Opawaho Health | 50 % of target |
| Te Ihutai Estuary Health | 30 % of target |
Thirty-one cents of every dollar you pay in rates goes to water. Not roads. Not parks. Not the stadium. Water.
Over the next decade, Christchurch City Council will spend approximately $2 billion on water infrastructure -- making it by far the largest category in the city's $5.2 billion capital programme. This article explains why the investment is so large, what it is being spent on, and what it means for your rates, your tap water, your rivers, and your estuary.
The Scale of the Network
Before we talk about money, let us talk about what Christchurch's water network actually looks like. The council manages approximately $8 billion worth of water assets, including:
- 1,700+ km of water mains delivering drinking water
- 1,600+ km of wastewater pipes carrying sewage to treatment
- 915 km of stormwater pipes managing rainwater runoff
- 45 stormwater pump stations
- 710 treatment basins and wetlands
- 12 km of stop banks for flood protection
- 7 wastewater schemes (Christchurch, Lyttelton, Governors Bay, Diamond Harbour, Akaroa, Duvauchelle, Wainui/Tikao Bay)
- Multiple water treatment and pumping facilities
If you laid all the pipes end to end, they would stretch from Christchurch to Perth, Australia. Managing, maintaining, and renewing this enormous network is the single biggest responsibility of the council -- and the single biggest cost.
Why So Much Spending? Three Big Reasons
Reason 1: Earthquake Damage
The 2010/11 earthquakes caused catastrophic damage to Christchurch's underground infrastructure. Pipes cracked, broke, and were displaced by liquefaction. Pump stations were damaged. Treatment facilities were compromised.
In the immediate aftermath, emergency repairs kept water flowing and sewage being treated. But many of those repairs were temporary fixes -- patches and workarounds that got the network functioning but did not restore it to full condition.
Fourteen years later, the city is still working through the backlog of permanent repairs and replacements. The earthquake did not just damage pipes -- it accelerated the aging of the entire network. Pipes that might have lasted another 20 years now need replacement. Joints that were fine before the quakes now leak. Ground movement created new stress points throughout the network.
The three waters pipe renewals programme has a budget of $148 million and is focused on replacing the most critical pipes across the network. Priority is given to pipes with the highest failure risk and those serving the most people.
Reason 2: Environmental Compliance
Christchurch's waterways -- the Avon/Ōtākaro, Heathcote/Ōpāwaho, Styx/Pūharakekenui, and the Avon-Heathcote Estuary/Te Ihutai -- face significant environmental pressure. Decades of urban development, combined with earthquake damage to wastewater pipes (causing sewage leaks into groundwater and waterways), have degraded water quality.
The council has consent conditions from Environment Canterbury that require it to progressively improve the quality of its wastewater discharge and stormwater runoff. Meeting these conditions requires massive investment:
Wastewater Treatment Plant Upgrades ($172M): The Bromley wastewater treatment plant is being upgraded with new activated sludge treatment and biogas storage. This is essential to meet discharge consent conditions for the estuary. Without these upgrades, the plant simply cannot treat wastewater to the required standard.
Stormwater Treatment: New filtration devices, treatment wetlands, and rain gardens are being installed across the city to treat stormwater before it enters rivers. Projects like the Addington Brook filtration devices ($5 million, fast-tracked by 5 years) and the Highsted/Styx Mill Reserve wetland ($3.4 million, fast-tracked by 3 years) represent the council's shift toward treating stormwater at source.
Akaroa Wastewater Scheme ($35M): The Akaroa wastewater scheme is replacing the ocean outfall discharge with a new land-based treatment and irrigation system. This stops treated wastewater going into Akaroa Harbour, protecting the marine environment and mahinga kai for tangata whenua.
The environmental imperative is not optional. These are legal requirements backed by resource consent conditions. Failure to meet them would result in enforcement action from Environment Canterbury and potentially the courts. More importantly, it is the right thing to do -- Christchurch's waterways are taonga (treasures) that deserve protection for future generations.
Reason 3: Population Growth
While earthquake recovery and environmental compliance drive the bulk of water spending, population growth adds another layer. Christchurch's population is growing at approximately 1.6% per year, with particularly strong growth in:
- Halswell: 4.5% annual growth rate
- Prestons: 8.5% annual growth rate
- Rolleston (Selwyn District, but connected to CCC water): 6.2% annual growth rate
- Belfast: 3.8% annual growth rate
- Wigram: 3.5% annual growth rate
Each new subdivision needs water supply, wastewater, and stormwater infrastructure. Development contributions from subdividers cover some of this cost, but not all -- particularly for trunk infrastructure (major pipes and pump stations) that serves multiple developments.
The water supply infrastructure upgrades programme ($185 million) includes capacity upgrades to treatment plants and the reticulation network to serve growing areas while maintaining service levels for existing residents.
Explore how your suburb is growing with our neighbourhood explorer.
The Drinking Water Story: Why Christchurch Is Special
Christchurch sits atop one of the most significant groundwater systems in the Southern Hemisphere. Deep artesian aquifers provide naturally pure drinking water that requires minimal treatment -- a rarity in modern cities.
The drinking water supply has a 100% compliance rate with New Zealand Drinking Water Standards. Unlike many cities that need extensive chemical treatment (chlorination, fluoridation, filtration), Christchurch water is drawn from deep wells and distributed with minimal processing. It is among the purest municipal water in the world.
However, this does not mean the water supply system is maintenance-free. The infrastructure that extracts, stores, and distributes water -- wells, pump stations, reservoirs, and 1,700 km of mains -- requires constant renewal. Mains breaks are disruptive, costly, and waste water. An additional $10.8 million has been allocated for mains renewals in the current annual plan.
The chlorination debate is also relevant. Following the Havelock North contamination incident in 2016, the government introduced requirements for all water supplies to either chlorinate or demonstrate secure bore sources. Christchurch has been granted temporary exemptions for its deepest wells but faces ongoing scrutiny. Any requirement to chlorinate the full supply would involve significant capital investment in treatment infrastructure.
The Stormwater Challenge: Flooding and Climate
The June 2025 floods demonstrated exactly why stormwater investment matters. Heavy rainfall overwhelmed parts of the stormwater network, causing surface flooding in several suburbs. While the system generally performed as designed for the rainfall intensity, climate change is increasing the frequency and severity of these events.
The council manages:
- 915 km of underground stormwater pipes
- 45 pump stations
- 710 treatment basins and wetlands
- 12 km of stop banks (flood protection barriers)
The stormwater and flood protection programme ($95 million) focuses on maintaining and upgrading this network. Key priorities include:
- Replacing aging pipes in flood-prone areas
- Expanding treatment wetlands for water quality
- Climate adaptation (designing for higher rainfall intensities)
- Temporary stop bank repairs after flood events
Stormwater renewal is currently at 40% of depreciation -- meaning the council is replacing assets at less than half the rate they are wearing out. This is a deliberate choice to manage costs, but it means a growing maintenance backlog that will eventually need to be addressed.
How the Investment Breaks Down
Over the 10-year Long-Term Plan (2024-2034), the approximately $2 billion water investment breaks down roughly as follows:
Pipe Renewals and Replacements (~$950M)
The largest single category. Includes:
- Three Waters Pipe Renewals -- $148M for the most critical replacements
- Wastewater Pipe Renewals across 7 schemes -- $88M
- Ongoing mains renewals -- additional allocations each year
- Emergency repairs and reactive maintenance
Wastewater Treatment (~$420M)
Includes:
- Bromley Wastewater Treatment Plant upgrades -- $172M
- Akaroa Wastewater Scheme -- $35M
- Pump station upgrades and renewals
- Odour control improvements
Stormwater and Flood Protection (~$380M)
Includes:
- Stormwater & Flood Protection programme -- $95M
- Addington Brook Filtration -- $5M
- Highsted/Styx Mill Wetland -- $3.4M
- Treatment wetlands and rain gardens across the city
- Stop bank maintenance and climate adaptation
Water Supply and Treatment Plants (~$250M)
Includes:
- Water Supply Infrastructure Upgrades -- $185M
- Well renewals and new wells
- Pump station upgrades
- Reservoir maintenance
- Potential chlorination infrastructure (contingency)
What Does This Mean for Your Rates?
Water infrastructure accounts for approximately 31 cents of every rates dollar -- or roughly $26.50 per week for an average property (CV $830,000). That breaks down into:
- Water supply rate: Based on CV, covers drinking water infrastructure
- Sewerage rate: Based on CV, covers wastewater collection and treatment
- Land drainage rate: Based on CV, covers stormwater management
- A portion of the general rate: Covers the operational costs of running the water services
If you want to see exactly how much of your rates goes to water, use our rates calculator which shows each rate component separately.
The significant water investment is a major reason why Christchurch rates have been high in recent years. But it is also why they are projected to moderate -- as the earthquake recovery catch-up is completed, the pressure on rates from water investment will ease.
See the projected rates trajectory in our 10-year outlook tool, which shows increases dropping from 6.6% in 2025/26 to around 2.8% by 2033/34.
The Environmental Scorecard
How is all this investment translating into environmental outcomes? Here is the current scorecard:
Drinking Water Compliance: 100% (Good) Christchurch drinking water meets all NZ Drinking Water Standards. Sourced from deep artesian aquifers, it is among the purest municipal water in New Zealand.
Avon River/Ōtākaro Health: Fair (Moderate) Water quality is improving thanks to stormwater upgrades, but urban runoff and aging pipes still contribute contaminants. Ongoing investment in stormwater filtration is expected to improve conditions over the next 5 years.
Heathcote River/Ōpāwaho Health: Fair (Moderate) The Heathcote has historically had poorer water quality due to industrial catchments. Multiple stormwater projects in Spreydon-Cashmere and Linwood-Heathcote are targeting improvement.
Te Ihutai/Estuary Health: Degraded (Poor) The Avon-Heathcote Estuary continues to face water quality challenges from sediment, nutrients, and treated wastewater discharge. The Bromley wastewater treatment plant upgrades ($172M) are directly aimed at improving estuary health.
Wastewater Overflow Events: Reducing (Moderate) Wet weather overflows are declining as the council invests in pipe renewals and capacity upgrades. The target is to halve median overflow resolution time from 24 hours to 12 hours.
Stormwater Treatment Coverage: Expanding (Moderate) New filtration devices and treatment wetlands are being added across the city. The shift toward treating stormwater at source represents a fundamental change in how the city manages water quality.
The Three Waters Reform: What Happened?
You may remember the government's Three Waters reform programme, which proposed transferring water assets from councils to regional water entities. That reform was scrapped by the incoming government in late 2023.
For Christchurch, this means:
- CCC retains ownership and management of all water assets
- The council continues to fund water investment through rates and borrowing
- There is no central government subsidy or co-funding for water infrastructure (unlike some other sectors)
- The council must meet all regulatory requirements independently
Some advocates argue that a regional or national water entity could have shared costs more efficiently. Others argue that local ownership keeps decision-making closer to ratepayers. Regardless of the politics, the practical reality is that Christchurch ratepayers fund the full cost of the city's water infrastructure through their rates.
Looking Ahead: The Next Decade
The good news is that the most intensive period of water investment is happening now. As the earthquake recovery catch-up progresses and major projects like the Bromley treatment plant upgrades are completed, the annual water capital spend will stabilise and then gradually decline as a proportion of the total capital programme.
Key milestones to watch:
- 2025/26: Akaroa wastewater scheme nearing completion. Addington Brook filtration commencing. Bromley upgrades continuing.
- 2026/27: Bromley activated sludge work rephased. Highsted wetland under construction.
- 2027-29: Biogas storage at Bromley. Continued pipe renewals.
- 2029-34: Focus shifts to growth infrastructure for new suburbs and ongoing renewals at sustainable rates.
The council is also progressively increasing its renewals rating -- adding $2 million per year -- to reduce the need for future borrowing. This is a prudent approach that spreads costs more evenly over time rather than creating boom-bust cycles.
The Bottom Line
Christchurch's $2 billion water investment is driven by three forces: earthquake recovery, environmental compliance, and population growth. It is the single largest category of council spending and the biggest driver of rates.
But it is also the most essential. Without it, pipes fail, sewage leaks into waterways, drinking water quality is at risk, and homes flood. The investment protects public health, the environment, and property values across the city.
At roughly $26.50 per week for an average property, water infrastructure is both the biggest line item on your rates bill and arguably the one that delivers the most direct benefit to every single resident.