The cities of Mountain View and Sunnyvale each owe $1,178,400 in civil penalties following multiple violations of the national Clean Water Act.
The Clean Water Act, passed in 1972, regulates water quality and makes pollutant discharge illegal in U.S. waters. According to the U.S. Environmental Protection Agency, this law also includes the discharge of oil or other hazardous substances, as well as failure to report said discharge.
In February 2020, the San Francisco Baykeeper, a nonprofit organization supporting environmental advocacy, filed a lawsuit against Sunnyvale and Mountain View for unsafe bacterial discharges into stormwater systems.
According to the SF Gate, the court ruling confirmed that E. coli levels in the water had surpassed the healthy water range, and tests before the ruling showed that the levels had been high for a significant time period.
According to the San Francisco Baykeeper, the two cities attempted to dismiss the case over five times and were denied by the court each time. The case went to trial in June 2025, in which Mountain View and Sunnyvale were found with over 1,200 violations of the Clean Water Act. According to the SF Gate, this conclusion was based on the presence of E. coli in stormwater ways and contamination with wastewater through those systems into nearby creeks.
“Sunnyvale and Mountain View have wasted years and squandered millions of taxpayer dollars fighting our lawsuits when they could have spent that time and money working with experts to fix their broken systems,” Baykeeper executive director Sejal Choksi-Chugh said in a statement. “Cities should be providing their residents with a healthy environment and local creeks that are safe for recreation, not fighting to keep polluting.”
The San Francisco Baykeeper claims that this incident was caused by exfiltration, where water leaks through defects in the sewage system to join the stormwater system. In the same ruling, it was concluded that these issues were a concern to public health, and both Mountain View and Sunnyvale were fined almost $1.2 million for not complying with mandated permit requirements by the Clean Water Act, according to NBC Bay Area.
According to the Los Altos Town Crier, this case is ongoing, and the two cities are attempting to find solutions. A permanent injunction on this issue will likely be determined in the summer.
