Upcoming challenges for our stormwater, wastewater and water supply systems

Seventy councils recently contributed to a survey to improve understanding of New Zealand's stormwater, wastewater and water supply systems.  Councils can use the results of this survey (called the National Information Survey) to assess how their approach compares to other councils facing similar circumstances, to learn what others are doing and to identify any opportunities for improvements.
Local Government New Zealand (LGNZ) identified three main challenges facing a number of councils:

1. Investing to replace and renew existing assets (which have a replacement value of $35.7 billion).

2. Investing to meet rising standards and increasing expectations (eg Drinking Water Standards, and compliance with wastewater and stormwater discharge consent conditions).

3. Providing end users with the right incentives to use water infrastructure and services efficiently (most councils use rates to charge for three waters services).
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Issue 1 – Replacing and renewing existing assets
The wastewater network has the highest replacement value at around $15.8 billion, followed by drinking water assets at $11.3 billion and stormwater at $8.6 billion.

Approximately one quarter of New Zealand’s assets in the water, wastewater and stormwater sectors are more than 50 years old and it’s likely that between 10-20 per cent requires renewal.

In addition to only being able to spread the costs over a small population, rural councils face higher renewal costs per property connection (more than twice the cost compared to metro council areas) for water infrastructure.

Issue 2 - Investing to meet rising standards and increasing expectations
These include the Drinking Water Standards, the National Policy Statement for Freshwater Management (as expressed through changes to water take and discharge consent conditions), and increased public expectations to be protected from stormwater flooding during storm events, which are becoming more intense and more frequent.

Issue 3 - Providing end users with the right incentives to use water infrastructure and services efficiently
Most councils do not incentivise water customers to save water through prices, as revenue to manage water primarily comes from rates. However, Tauranga observed a 30 per cent fall in peak demand for water following the introduction of water meters and volumetric charging. A similar reduction in demand was observed in Carterton when it introduced similar schemes. The savings generated by Tauranga’s metering and charging system have been estimated at around $4.7 million per year over a 30 year period of analysis.
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The LGNZ paper identifies that metering will provide benefits for councils that have one or more of the following conditions:

• Increasing demand
• Limited knowledge of network performance (information from metering can assist with targeted programmes, such as leak reduction initiatives)
• Scarce water supply
• High treatment costs.
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This information was sourced from the LGNZ publication ‘Exploring the issues facing New Zealand’s water, wastewater and storm water sector’. LGNZ is publishing a follow up paper in early 2015 which will evaluate options to address these issues.