About this decision

The age of our pipes, and a series of recent high profile pipe failures - particularly in the wastewater network - has put the condition of the network in the public spotlight.

For a long time, te Wellington region's three waters network has only had low funding. Wellington Water have recommended to its client councils that an increase in funding is needed over several years.

What's the background to this decision?

The three waters network means our drinking water, wastewater and stormwater infrastructure including:

  • 2653km of pipes
  • 193 pump stations
  • 3 treatment stations
  • 65 reservoirs

The network replacement cost is about $3.9 billion. The Council owns the city's water infrastructure, and Wellington Water Limited (owned by the region's Councils) manages the network and is responsible for providing clean, safe drinking water and efficient wastewater and storm water services.

We know we have some big problems with our very old pipes. We can’t fix our water infrastructure all at once and it’s very expensive. So we need to focus on the most critical parts and main trouble spots first.

The 2020 Mayoral Taskforce on three waters investigated the condition, funding, and management of the network and made recommendations for improvement. The Taskforce's 48 recommendations included accelerating the renewals of old drinking and wastewater pipes, valves and pumps, carbon management, and funding.

The ability of the local contractor market to deliver the work is a concern. Wellington Water is increasing its ability to do things smarter. If the improvement programme can't be delivered as planned, the Council will prioritise renewals work to prevent pipes failure, review the planned upgrade work programme and see if some work can be delayed.


There are three options

Option 1:
Maintain Current Funding Level
Option 2:
Enhanced Investment (preferred)
Option 3:
Accelerated Investment
Option one is continuing the existing level of funding for three waters renewals. With no new investment the Council expects an increasing number of leaks, burst pipes, and more water lost.

There are risks with this option such as:
  • lower in service levels from Wellington Water (dealing with more leaks) and;
  • we won't know significantly more our about the condition of the pipes e.g. which ones might fail
Not getting ahead of replacement of some vulnerable pipes may results in the need to construct more water storage (could cost hundreds of millions).

We don't believe this is what most Wellingtonians want
This option has a substantial increase in the level of three waters investment - well above the last 10-year Plan.

The investment includes:
  • funding to complete Omāroro reservoir
  • improving our knowledge of the condition of pipes to improve the timing of pipe renewals; and
  • an extensive programme of pipe replacements.
We think this will help reduce the recent trend of unpredictable leaks and burst pipes.

However, we do not think this option will fix all of our network problems over night.

The risk is that some Wellington Water service levels may continue to decrease and therefore increase operating costs

Option 3 is a substantial increase in investment over Option 2.

The aim is to significantly speed up:
  • all work programmes across the network
  • investigations into the pipes condition
  • a big pipe replacement programme (more than Option two); and
  • better understand the carbon footprint of the network.
However option three is not our preferred option because:
  • we don't know enough about the condition of pipes to properly cost and direct the investment; and
  • there is significant uncertainty regarding the ability to deliver a large programme of work
Option cost and how much debt?
$552m over 10 years
Option cost and how much debt?
$678m over 10 years
Option cost and how much debt?
$1.5b over 10 years
Rates change:
No impact
Rates change:
2.51% 3 year average increase
Rates change:
5.85% 3 year average increase


Our preferred option

The Council prefers Option 2: Enhanced Investment which focuses on improving the condition and reliability of the network in an affordable and sustainable way. This option includes funding for wastewater laterals (see Decision 2) but does not include the cost of sludge minimisation (Decision 7) that is proposed to be funded externally (not by the Council).

Note: Our external Auditors have made specific comment on the three waters decision in their opinion in the consultation document - see pages 72-74 of the consultation document available at the link below.

Want to know more about our 7 big decisions? Head back to our Long-term Plan homepage or read our full consultation document.