BOM National Performance Report 2020-21:
A wastewater snapshot
Each year the Australian Bureau of Meteorology releases the National Performance Report for urban water utilities, the 2020-21 report is available for public download here: http://www.bom.gov.au/water/npr/
This annual report aims to provide benchmarking of pricing and service quality for urban water utilities. The report is helpful for utilities to monitor annual trends within their own organisations, as well as look at whether their key metrics sit within the typical range in a broader national context. Utilities are grouped within four size categories (small, medium, large, major). This reflects that revenue base and population density can be a factor in both the cost required to provide water and sewer to customers as well as the level of service that is appropriate or sustainable.
Running to 128 pages, this is a comprehensive report that lists metrics across 166 categories from 86 utilities. Dependent on your area of expertise or interest, there is interesting information for everyone.
This article summary focuses on some of the key metrics that relate to gravity sewer mains and wastewater expenditure.
Sewer Main Breaks and Chokes
To enable comparative analysis, many of the metrics are reported as ‘per 100km of asset’, this is the case for ‘sewer mains breaks and chokes’.1 This last year has seen improvements for many locations with 57% of utilities reporting a decrease in breaks and chokes compared to the previous reporting year with Clarence Valley Council, Gippsland Water, and Gladstone Regional Council all seeing reductions of > 75%.
Utilities reporting the lowest instance of breaks and chokes in each utility group size is listed in the table below.
Table 1: Number of sewer mains breaks and chokes per 100 km (Indicator A14)
|Small (10,000 – 20,000 properties)||Water Corporation – Geraldton (WA)||3.4|
|Medium (20,000 – 50,000 properties)||Tweed Shire Council (NSW)||1|
|Large (50,000 – 100,000 properties)||Gippsland Water (VIC)||1.5|
|Major (100,000+ properties)||City of Gold Coast (QLD)||3.8|
Major utilities saw the largest improvement for this metric. However, reductions were not the norm for small-sized utilities with the median increasing from 13.7/year to 15.6/year, and the average increasing from 25.3/year to 35.5/year.
Capital Expenditure per Property (Wastewater)
The report notes that the national median per property capital expenditure on wastewater services decreased by 11% from 2019-20 to 2020-21.
Utilities reporting the lowest wastewater expenditure per property in each utility group size is listed in the table below.
Table 2: Capital expenditure per property – wastewater (Indicator F29)
|Small (10,000 – 20,000 properties)||Gympie Regional Council (QLD)||$88.90|
|Medium (20,000 – 50,000 properties)||Dubbo Regional Council (NSW)||$3.65|
|Large (50,000 – 100,000 properties)||Power and Water Corporation – Darwin (NT)||$146.72|
|Major (100,000+ properties)||City West Water Corporation (VIC)||$143.57|
Looking more closely at the data split by utility size, the average annual capital expenditure on wastewater is surprisingly similar across all utility sizes; in the region of $275 to $300 per property. The reported figures over the last decade do indicate that small and medium sized utilities may be investing less, on average, on wastewater infrastructure.
While there may be a variety of reasons for this, it will be of some concern if a trend of reduced investment is reflected in a similar reduction in wastewater service level KPIs (including sewer main breaks and chokes).
Despite the significant reported drop in per property wastewater expenditure over the last year (11%); the overall reported capital expenditure on wastewater has remained reasonably stable since 2017 at around $2.7 billion dollars per year – with a drop of 2.9% from 2019-20 to 2020-21 based on reported figures.
Wastewater Operating Cost per Property
The report saw 66 of 86 utilities submit data on operating cost per property to supply wastewater services. The following utilities in each category reported operating their networks at the lowest cost:
Table 3: Wastewater operating cost per property (Indicator F14)
|Small (10,000 – 20,000 properties)||City of Kalgoorlie-Boulder (NT)||$168.96|
|Medium (20,000 – 50,000 properties)||Rockhampton Regional Council (QLD)||$294.59|
|Large (50,000 – 100,000 properties)||Toowoomba Regional Council (QLD)||$243.35|
|Major (100,000+ properties)||South Australian Water Corporation (SA)||$231.92|
Residential Wastewater Bill
The cost to provide services is impacted by a wide range of factors, including but not limited to: age of assets, condition of assets, density of population, climate and topography. The table below lists the lowest residential wastewater bill in each category for the 20/21 period.
Table 4: Typical residential wastewater bill (Indicator P14)
|Small (10,000 – 20,000 properties)||Armidale Regional Council (NSW)||$465|
|Medium (20,000 – 50,000 properties)||Lower Murray Water (VIC)||$491.84|
|Large (50,000 – 100,000 properties)||North East Region Water Corporation (VIC)||$239.16|
|Major (100,000+ properties)||City West Water Corporation (VIC)||$347.92|
The report indicates 57% of utilities had a reduction in the typical residential wastewater bill with Central Coast Council seeing the largest change (-24%). However nationally, the overall trend was only marginal (<1% decrease).
1 Wastewater mains breaks and chokes is intended to include:
- Gravity sewer mains
- Rising (pumped) mains
- Low pressure mains
- Vacuum system mains
- Property connections
- Treated effluent mains
- Recycled water mains
It can be questioned whether failures on pumped rising mains and chokes within gravity sewer networks should fall under the same metric. While these asset types are intrinsically connected to form the majority of a sewer network, they operate under very different conditions and the mode and cause of failure are often quite distinct.
The information and data for this snapshot is sourced from Part A and Part B of the National performance report 2020–21: urban water utilities. It has been used under the Creative Commons Attribution 3.0 Australian License.
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