Oak Hill Municipal Well Project


Project Description

The Oak Hill Well, as part of the the Well Construction Program, will expand the City’s groundwater well network, creating a new reserve water source for use in emergencies and times of severe drought when other sources are diminished or not available. Ultimately, the goal of the Well Construction Program is to help our City utilities infrastructure (and the community with it) become more flexible and more durable to withstand water supply and climate stresses.

Currently, most of Petaluma’s groundwater wells are located on the City’s east side. The Oak Hill Well site was selected as a priority due to its proximity to the water distribution system and location within a high-yield groundwater aquifer.

Please review the list of frequently asked questions located at the bottom of this webpage to learn more.

Project Update

You last heard from us in November when we shared plans to push our Oak Hill Well construction start date until after the holidays. We are now crossing the final items off of our pre-construction checklist and anticipate construction of the well to begin in early April.

Well construction is expected to last 4 to 6 weeks. Actual drilling should only take approximately 5 days (drilling will occur for a couple of days, then pause to fine tune final placement, then resume for a couple of days until finished).

We have updated our site plan to include sound walls around the complete construction site, rather than the smaller sections that were originally planned. This will help reduce construction noise and ensure the least disturbance to park goers and residents.

If you have additional questions, feedback, or concerns, please call or email project manager, Dan Herrera: [email protected], 707-778-4589.

Thank you for your patience as we check off the final items on our pre-construction checklist and move forward with this important project.

What’s next?

The City will offer more opportunities to learn about the project and give input. Stay tuned to this webpage and sign up to receive updates to hear about upcoming events.

Community Input

Thank you to everyone who has expressed interest in the Oak Hill Well project. Please sign up using the form below to receive project updates on information about upcoming community input opportunities.

On-Site Walking Tour - November 2023

We hosted an on-site walking tour to discuss the project November 2, 2023. Thank you to all who joined us!

3rd Community Meeting - October 2023

We held our 3rd community meeting on Zoom October 30, 2023 to review the project and construction schedule. Thanks to everyone who took the time to attend. We appreciate the thoughtful questions and input received.

Missed the meeting? No problem! Click HERE to view a recording.

2nd Community Meeting - June 2023

On June 1, 2023 we held our second community meeting (this time virtually via Zoom) to review the project construction schedule, discuss visual elements of the well, explore next steps for the Oak Hill area, and address questions/concerns. Thank you to the 14 community members who joined us.

CLICK HERE to view the PowerPoint presentation.

CLICK HERE to view a recording of the meeting.

1st Community Meeting - August 2022

Thank you to everyone who attended the community meeting on August 11, 2022 to learn more about the proposed Oak Hill Well project. To view the presentation posters referenced during the meeting, CLICK HERE. The frequently asked questions answered at the bottom of this webpage have been updated based on the the meeting's discussion.

Project Location

35 Park Avenue, Petaluma

Traffic Impacts & Benefits

Access to walkways around the Oak Hill reservoir may be impacted or restricted during construction. Walkways will reopen after construction is complete.

Timeline/Project Status

City Council unanimously approved the Oak Hill Well project at the September 12, 2022 meeting.

The California Environmental Quality Act (CEQA) compliance and design has been completed. A mitigated negative declaration/Initial Study was approved by City Council at the September 12, 2022 meeting. It can be viewed here: Oak Hill Municipal Well Project Initial Study / Mitigated Negative Declaration (IS/MND).

The project was paused briefly as the County of Sonoma, in an effort to conserve water during extreme drought, instituted a moratorium on the creation of new wells. This moratorium is expected to expire in May 2023, at which time City staff will begin the bidding process for the well construction project.

We are currently reviewing proposals from contractors and working to ensure those we are considering meet all our requirements. Construction of the well is expected to begin in late fall of 2023 and anticipated to be completed by spring of 2024.

Community outreach will continue throughout the design and construction phases to update and inform the neighborhood. Please sign up using the form on this webpage to receive project updates and information about upcoming community input opportunities.


Water Enterprise Funds

Bid Details


Oak Hill Municipal Well Project MAP (1)

Sign Up to Receive Project Updates

Oak Hill Tank Replacement Project

Oak Hill Tank is an important part of the Petaluma’s water distribution and pressure system, including fire protection, for the downtown area. The tank was decommissioned in 2015 due to required maintenance and upgrades. We look forward to working with our community to create a new tank that better serves the needs of Petaluma.

Learn more and sign up to receive updates on the Oak Hill Tank Replacement project webpage: cityofpetaluma.org/oakhilltank

Located at 35 Park Avenue, this project will install a new municipal groundwater well to provide local water to Petaluma residents. This project will provide water generated from a well located in the western portion of the City.

The City of Petaluma is working to enhance our ability to supplement our water supply with local groundwater when needed. Some short- and long-term situations that can limit our supply of water or require more water than we typically receive include: 

  • Infrastructure failures such as broken pipes 
  • Extreme drought 
  • Large-scale disasters such as wildfires 
  • Several situations occurring at different locations throughout the City at the same time (such as fires, infrastructure failures) which would increase demand beyond our capacity to maintain sufficient flow rates and pressures.  

The City is working to be able to provide more of our water from local sources so that we can supply our needs when necessary.  Currently, our city is mostly reliant on surface water purchased and imported from the Russian River system from our water supplier, Sonoma Water. The proposed well at Oak Hill is one of several ways we plan to achieve our goal of increasing our local water supply. 

The new groundwater well at Oak Hill would: 

  • Provide an additional water supply and pressure point for fire protection in the western portion in the city.    
  • Provide an additional groundwater supply well to our existing municipal well field  
  • Strengthen the City’s local water supply on the west side of Petaluma within Zone 1 of the City’s distribution system.  Currently, most city-owned groundwater wells are located on the north and east sides of town.  

Our region is currently experiencing extreme drought conditions that are expected to continue into the foreseeable future.  Water Conservation has become a way of life for California residents, including for us in Petaluma, and our community has demonstrated outstanding efforts to conserve water through the drought. The proposed well at Oak Hill will increase our local water supply, make us more resilient in the face of water adversity, and assist in meeting our allotment restrictions from our water supplier during periods of drought.  

The City of Petaluma, through its agreement with Sonoma Water, is committed to providing at least 40% of our water needs locally. CLICK HERE for additional information about the need for and benefits of this project. 

The overall project should take approximately three to four months for completion, with the drilling of the well being a portion of that time. The well itself will be underground with only a small vault structure or decorative well cap at ground level for access and maintenance activities. In the current plans, a small well building (12×14 feet in size) will be constructed to house equipment to pump and treat the water. We plan to construct the well building in such a way as to retain a walking path around the reservoir. When and if the design of the project moves forward, we will seek input and feedback from the community on the aesthetics of the well building.

Yes, a diluted chlorine solution (similar to household bleach) used to treat the water will be stored in the well building. A dedicated drainage system on-site is designed to contain any spillage or waste from the site.

Oak Hill has historically been a water storage location in Petaluma. As such, needed land, existing utilities, and connections to the distribution system are already in place to support a well. In addition, the Oak Hill site is the only site connected to the city’s Zone 1 distribution system, which encompasses the majority of the City and has the highest water demand. Thus, Oak Hill was selected as the best location to extract water to support the City’s water needs.

Currently, we are in the planning stage of the project, which includes confirming that the project meets the requirements of the California Environmental Quality Act (CEQA). An Initial Study has been completed and it has been determined that, through mitigation measures, this project would not negatively impact the environment.   

As we continue to work through the planning stage, our next steps include involving the community, specifically residents who reside or spend time in the area around Oak Hill Park, in discussions about the project. We are planning on hosting a community meeting at the project site on August 11, 2022, from 6 pm to 8 pm. Stay tuned to our City website, Community Update emails, and the project webpage, cityofpetaluma.org/oakhillwell, for more information about upcoming meeting and opportunities to get involved.

A location on Paula Lane and on Magnolia Open Space were considered. These locations lack the needed infrastructure to connect to our current water system.  These sites are connected to the city’s Zone 2 of the City’s water distribution system, which is much smaller and has lower demand than Zone 1. However, these locations may be the sites for future additional wells as needed to support city needs, and to meet local supply goals. A siting study was completed in 2019 to help determine potential well locations. CLICK HERE to view the staff report that summarizes the study.

When the City Council considers an action related to how a project will affect the environment, the noticing and public meeting requirements are tailored to the size and impact of the project. The City will be hosting a community meeting at the project site on August 11, 2022 from 6 pm to 8 pm. The community meeting will provide an opportunity to further discuss the project, proposed improvements, environmental considerations, and public input. The City also intends to host additional community meeting(s) during the design phase of the project.

The noticing requirements are based on what the study identifies in terms of possible environmental impacts – the more significant the impacts, the more noticing required. In the case of this project, several notices were required and completed. Notifications were sent to:

  • Tribal representatives of California Native American tribes 
  • The Public
  • Responsible trustee agencies  regulatory agencies and stakeholders, etc.)
  • Sonoma County Clerk
  • State Clearinghouse

The CEQA document was circulated for 30 days, from April 28, 2022, to May 27, 2022, to allow the public and agencies the opportunity to review and comment on the document.

The Initial Study and Mitigated Negative Declaration completed for this project determined that with implementation of mitigation measures, the project would not have significant environmental impacts. Therefore, staff did not hold a community meeting.

Because this project did not have significant impacts, direct notices were not sent to neighbors. Instead, the typical public noticing requirements CEQA guidelines was completed as noted in the FAQ that discusses noticing requirements.

Anyone can review the Initial Study and Mitigated Negative Declaration to learn more about the project and how it was determined to not have significant environmental impacts through mitigation measures. The CEQA document is available for public review online at https://cityofpetaluma.org/capital-improvements-program/. The public is also invited to a community meeting that will be held at the project site on August 11, 2022, from 6 pm to 8 pm to further discuss the project, proposed improvements, environmental considerations, and public input. Also, Dan Herrera, the project manager can answer questions.

CEQA requires public agencies to “look before they leap” and consider the environmental consequences of their discretionary actions. CEQA is intended to inform government decisionmakers and the public about the potential environmental effects of proposed activities, to identify ways environmental effects can be avoided or reduced, and to disclose an agency’s decision-making process and to prevent significant, avoidable environmental damage.

An Initial Study is a preliminary analysis prepared by the lead agency to determine whether the project may cause a significant environmental impact and weather an environmental impact report (EIR) or negative declaration (ND) must be prepared.

An Initial Study facilitates environmental review early in the design of a project, enables mitigating adverse impacts, and provides a basis for determining what type of environmental document to prepare.  A Mitigated Negative Declaration is a finding that a lead agency makes when the initial study shows that the impacts of a project can be reduced to less than significant with mitigation.

The proposed well has several design considerations that will alleviate concerns regarding groundwater depletion and impacts to nearby building foundations. First, the well will be drilled to a depth of approximately 500 feet and pull water from an aquafer this is located in a deep, hard rock formation. Second, the well will be lined with a 100-foot deep concreate sanitary seal. Finally, the well construction will include foundation supports. All these design elements will assure that the well will not cause surface soil to subside in the area as a result of the well itself.

The Initial Study completed for the project did not identify significant unavoidable environmental impacts that would warrant a more comprehensive study such as an Environmental Impact Report. The Initial Study determines the appropriate level of compliance document, and in this case, a Mitigated Negative Declaration was deemed the appropriate document.

No, this project will not change the way water drains from the site. There will only be minimal disturbance to soil during construction. Drainage patterns at the project site would remain essentially the same as they currently exist. The project would result in only a minor increase in impermeable surfaces associated with the well treatment shed (approximately 250 square feet) and the well vault. Construction and operation of the project would not substantially alter drainage patterns or increase runoff, and erosion or siltation is not anticipated.

Yes. Groundwater generated during the well development, pumping tests, and start up events can be captured and repurposed if need.

Yes, in some cases, the water that comes from the well has mineral levels that need to be treated before it can be discharged in the sewer system. We don’t believe that this is a likely outcome, but we will continue to monitor during construction to be sure the well water quality is safe. Future water from the well will be analyzed and only discharged to the sewer if it is safe.

The only way to test the water would be to drill a well. We will test the water as the well is drilled. However, to inform our project, we did review the water quality of a well located near this site. That water quality review indicates that there is a low likelihood that we will have water quality issues at this site.

Any situation that disrupts the ability to deliver water or meet the needs of the community would be considered an emergency. The residents in the immediate vicinity of Oak Hill will benefit from the supply and pressure from the well, but ultimately, the well can be used by the entire community of Petaluma.

There are general known formations described as “Wilson Grove Formations” and “Fractured Bedrock”. The exact formations and types of soil that will be encountered during the drilling process and depths are variable.

The pump is a submersible type of pump and will be located hundreds of feet below the ground. The well will be virtually silent. The minimal sound being generated will most likely come from the electrical equipment in the well house.

The City has an aquifer storage recovery study in the planning stages, which will evaluate using wells for injection to later be used as a potable water supply source.

It is possible that restrictions from Sonoma Water, the City’s main water supply source, will cause the City to need to use more local supply throughout the year. The CEQA document limits the amount of water able to be produced from the well at a little over 200 AFY.

The well will be located in the general vicinity of the labyrinth, but the exact location is not known. The location will be finalized to facilitate construction activities, equipment, and materials.

Yes. The City is currently delivering recycled water to golf courses, City parks, schools, and other landscaping areas. The City is actively expanding the recycled water service area.

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