Eric Tynan, general manager of Castroville Community Services District, often calls Castroville’s water supply challenges “the canary in the coal mine” for the northern Salinas Valley. Castroville CSD has three wells in the 400-foot aquifer. One had to be shut down in March 2021 because it became too salty, and the other two remain in constant danger of the same fate due to ever-increasing seawater intrusion in the aquifer. The district’s other well is in the deep aquifer, which is around 900 feet deep and contains water believed to be several thousand years old – a water supply that is not replenishing. Add to that problem, Tynan says, its water comes out hot (99 degrees).