The City Council approved two important plans at the last meeting that will likely become the largest project in King City’s history. These include an updated Master Plan for the City’s wastewater collection system and a Facility Plan for the wastewater treatment plant, which are challenging projects for a small community to undertake.

Both plans were prepared by Carollo Engineers, a leader in designing wastewater treatment facilities. City staff has worked hard to develop the most cost effective approach to this effort, and there does not appear to be any way to avoid the need to confront this issue at this time.

Both the City’s collection system and treatment plant are outdated and beyond their anticipated life span. The treatment plant does not have sufficient capacity to serve the City’s projected buildout population or even all projects that have been permitted. The Regional Water Quality Control Board will not approve expansion of the current plant without significant upgrades. The Board has also indicated King City’s plant would be identified for enforcement action if the City were not pursuing this planning effort because it does not meet their existing standards. 

At a minimum, the City will be required to upgrade the plant to a “secondary treatment” level. However, it would be ideal to upgrade it to what is referred to as “tertiary treatment” because that is probably what will be required by the State in the future and it would provide usable recycled water. A recycled water system could reduce groundwater pumping and expand the City’s water supply, particularly during drought conditions.

To reduce costs to the City’s wastewater customers, it is proposed to establish a partnership with California Water Service (Cal Water) since they are the water purveyor in King City. Under this concept, the City would pay for costs to upgrade the facility to secondary treatment. Cal Water would then be responsible for the additional cost for tertiary treatment, as well as the cost for the recycled water distribution system. In exchange, Cal Water would be able to sell the recycled water, which would generate revenue and help protect the overall potable water supply. The City is also working on strategies to fund a significant portion of the project costs from a number of grants, which will be critical to making the project feasible.

It is proposed to accomplish the project in phases based on when the capacity is needed. The projected costs to the City for Phase I include approximately $32 million for construction and an annual increase of $350,000 for maintenance. In addition, the Wastewater Collection System Master Plan recommends replacing deficient pipes on an ongoing annual basis for the next 20 years, which will result in an estimated $240,000 annually.

Now that the City has accurate projections of future costs, it has the data needed to prepare a comprehensive study to determine appropriate rates for the future. Therefore, the next steps will be to prepare a recycled water study and a wastewater rate study. The goal will be to develop an overall revenue plan that can be implemented over a five-year period, which is the projected timeframe for the wastewater treatment plant project. The City has received a number of requests to change residential rates to a more volume based approach so rate structure options will also be prepared for the City Council to consider.

Please feel free to contact City Hall at 385-3281 if you have questions. Copies of the full Wastewater Collection System Master Plan and Wastewater Treatment Plant Facility Plan can be found on the City’s website at under Documents and Forms, Public Works Department.

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A staff member wrote, edited or posted this article, which may include information provided by one or more third parties.


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