County officials approve new groundwater well drilling after failed casing repair

The Planning Commission meeting held on June 23, 2025, in Sunnyvale, Santa Clara County, focused on critical discussions regarding the rehabilitation and replacement of a failed well, as well as safety measures for water treatment processes.

The meeting commenced with an update on the well casing failure, which necessitated the abandonment of the existing well due to deterioration. Officials explained that attempts to rehabilitate the well were unsuccessful, leading to the decision to drill a new well approximately 1,000 feet deep. This new source is essential to restore water supply capabilities, especially in light of recent environmental challenges such as fires and changing weather patterns. The goal is to achieve a flow rate of between 1,200 to 2,000 gallons per minute (GPM) from the new well.

Safety protocols for the water treatment process were also a significant topic of discussion. The commission addressed the use of sodium hypochlorite and ammonia in the treatment facility, which, when combined, create chloramines for disinfecting water. Officials assured that stringent safety measures are in place, including double containment systems and alarms to detect any chemical leaks or failures. Daily monitoring is conducted to ensure the integrity of the system.

Commissioner Serna raised concerns regarding potential contamination of the water supply. In response, officials confirmed that water samples would be tested according to California's Title 22 regulations during the drilling and completion of the new well. They emphasized that any contamination would be identified through these tests, and the well would not be put into service if contamination were detected.

The discussion also touched on the consideration of desalination as an alternative water source. However, it was noted that this option was rejected during the environmental review process due to concerns about its environmental impact and its inability to meet project objectives.

In conclusion, the meeting underscored the urgency of addressing the well failure and the importance of maintaining safe water supply standards. The commission plans to proceed with the drilling of the new well while ensuring that all safety and environmental regulations are strictly followed.