Wastewater System - Mount Elgin

The Mount Elgin Wastewater Treatment Plant (WWTP) provides wastewater treatment for residential, commercial, and industrial users in the Village of Mount Elgin. Within the wastewater collection system, individual properties are serviced by septic tanks where sewage is pretreated to remove solids and grease before discharge to a small diameter variable grade sewer. The small diameter collection mains direct the primary treated effluent to a sewage pumping station, to be conveyed to the WWTP.

Inventory

The replacement cost valuation for the linear assets in this portfolio are based on current tender prices, where available. The replacement cost valuation for wastewater vertical is based on the latest information available, which includes current replacement costs, insurance valuations, inflation, and valuations from studies and assessments completed in prior years.

Condition

The percentage of assets in poor or critical condition has increased from 17% as reported in the 2024AMP to 18%. The percentage of assets in good or excellent condition has decreased from 81% as reported in the 2022 AMP to 78%. As assets continue to age their condition rating will decline until lifecycle strategies are triggered and completed.

Key Performance

It is intended that all wastewater assets will be maintained, rehabilitated, and replaced to perform the same function and manage the same capacity as they are currently designed to do. To ensure levels of service are maintained, staff monitor impacts from changes to capacity demands to plan for changes to current practices and budget requirements.

Proposed Levels of Service Review

Information on the scenarios reviewed is contained within the AMP document. As the system’s reserve balance and proposed funding under all scenarios are sufficient to fund the short-term needs, the average expected condition of the portfolio is the same under all scenarios for approximately 8 years, which aligns with the 2025 Budget Survey responses where 61% of respondents indicated that the service level related to municipal water and wastewater services in South-West Oxford should be maintained. 

Based on the analysis, staff are recommending Scenario C. The proposed level of service target is to fund the system at 60% of overall lifecycle needs. The use of PVC pipes for linear started becoming popular in the 1970’s; their useful life of 90 years is theoretical as this material has not been in use long enough to confirm the lifespan. Staff also identified an improvement area in 2024, to look at the lifecycle strategies for process assets as it may be beneficial in the long-term to incorporate various strategies and not anticipate a run-to-failure strategy on some of these assets. Once incorporated this may result in reductions to the annual investment required, as such staff feel it is not prudent to target the fully funded scenario at this time. Staff will continue monitoring asset conditions and risks to ensure the proposed service level does not negatively impact on the overall health and safety of residents through the operations of this service.

Funding Gap Analysis

Planned Investment Level

An estimated inflationary rate is used in the table below as the inflation rate used for the 2026 Budget is based on the rate as of June 30, 2025. An estimated capital contribution resulting from growth has been included in the table as growth will play a significant roll in meeting the funding requirements for the Mount Elgin wastewater system. Based on recent market fluctuations it is difficult to ascertain how quickly growth may happen, and thus when the additional rate revenue will be available for use towards the system’s operating and capital requirements. Slow or delayed growth may require additional rate increases for short-term sustainability. The impacts of growth and sustainability of the system will be monitored.

Proposed Investment Change

In addition to the planned investment level changes, an increase in the contribution to the Wastewater – Mt Elgin reserve of approximately 2% is proposed for 2026 through 2035. Although this only amounts to approximately $3,000 in 2026, the result is an estimated $0.86 increase in the monthly fixed charge for the average residential user or $10.32 annually. The Wastewater – Mt Elgin system has a higher fixed rate within Oxford County; as such it would not be prudent to propose a higher increase at this time given the unknowns around growth.

Comparison of required investment to proposed investment (millions)