Wastewater System - Woodstock

The County maintains a diverse portfolio of assets that are required to provide City of Woodstock residents and businesses with the safe collection and treatment of wastewater. The Woodstock Wastewater Treatment Plant (WWTP) provides wastewater treatment for residential, commercial, industrial, and institutional users in the City of Woodstock, as well as for the communities of Embro and Innerkip. It also provides treatment for septic tank waste, hauled waste, and holding tank waste from within the County.

The wastewater collection network consists of a mix of gravity mains, low pressure mains and forcemains. Wastewater flows by gravity wherever possible or by the use of sewage pumping stations (SPS) where changing elevations require. Other specialized structures such as maintenance holes, valve vaults, meter stations, diversion structures and siphons are required to convey wastewater 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. Quantity changes are attributed to refinements and updates made to the inventory, ensuring more accurate and current data.

Condition

The percentage of assets in poor or critical condition has increased from 37% as reported in the 2024 AMP to 38%. The percentage of assets in good or excellent condition has decreased from 36% as reported in the 2024 AMP to 34%. As assets continue to age their condition rating will decline until lifecycle strategies are triggered and completed.

Key Performance

The wastewater network collects and treats the wastewater from homes, businesses, institutions, and industry. Wastewater travels through the sanitary sewer system to the WWTP for treatment. 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 investment levels.

Proposed Levels of Service Review

Information on the scenarios reviewed is contained within the AMP document. 72% of respondents through the 2025 Budget Survey indicated that the service level related to municipal water and wastewater services in Woodstock should be maintained. An overall decline in condition as assets age is planned and represents an efficient and cost-effective way to manage assets.

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.

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. As the payment for debt obligations declines those funds are re-invested and are included in the planned investment level in the table below. Although interest rates are declining, the reserve balance will continue to earn interest and contribute to the
planned investment. 

Proposed Investment Change
In addition to the planned investment level changes, an increase in the contribution to the Wastewater – Woodstock reserve of approximately 5% is proposed for 2026 through 2028, reducing to 2.5% for 2029 through 2035. Although this is a 5% increase in the reserve contribution, the result for 2026 is an estimated $0.50 increase in the monthly fixed charge for the average residential user or $6.00 annually.

Comparison of required investment to proposed investment (millions)