Stanislaus County OKs $10.8M project to upgrade neighborhood with well contamination
Stanislaus County supervisors last week approved a construction contract for improvements to Riverdale Park Tract, another urban pocket that’s benefitting from American Rescue Plan Act funds.
The $10.8 million project was awarded to Mozingo Construction of Oakdale to improve the unincorporated pocket in southwest Modesto with sidewalks, curbs and storm drainage, as well as water mains to deal with well contamination. Ghirardelli Associates will handle construction management.
The county has used federal ARPA funding to upgrade several urban pockets that don’t have modern infrastructure. Riverdale Park is an enclave of homes near the Tuolumne River along Parkdale Drive and West Hatch Road.
Some improvements are expected to reduce localized flooding in the neighborhood and provide sidewalks for pedestrians.
Mozingo was the lowest bidder among six contractors in the competitive bid process. The company submitted a base bid of $7.3 million for the county’s ARPA-funded improvements and an alternate bid of $3.5 million for the city of Modesto’s drinking water improvements, which are funded through the state.
Construction is expected to begin this month and will be completed next winter. The city and county have a cost-sharing agreement for the project, because both entities had plans for improvements of Riverdale Park Tract.
Modesto was able to obtain funds from the State Water Resources Control Board. The city has worked with the Riverdale Park Community Services District to upgrade the district’s water system serving about 200 homes.
A district well has been contaminated with traces of perfluorooctonic acid and a related chemical. State regulators have concerns that exposure to the chemicals over certain levels in tap water may result in adverse health effects such as thyroid toxicity, reproductive problems and cancer.
Neighborhood residents, owners of the nearby Bonzi Sanitation Landfill (which is closed) and the state have battled in court over who’s responsible for contamination of Riverdale’s water.
This story was originally published March 24, 2026 at 5:30 PM.
