I lived in the South Bay from the late 1970s through most of 2018 (college, work, marriage, kid, retirement). The weather may be nice there, but air quality has suffered for years.
I used to drive to and from the Santa Cruz area over a decade ago, and you could see the haze over the valley as you drove down HW 17. The numerous wildfires, especially the Camp Fire in November 2018 (we left CA for good two weeks prior), hasn't help.
The drinking water wasn't much better. Heavily chlorinated, to the point where it would dry out your skin. You could smell the chemicals in the shower. Pour water into a pot to boil for pasta, and the water would be cloudy.
Most years, there wasn't enough water in storage, and with Anderson Dam (over 50% of Santa Clara County's above-ground water storage capability) down to 3% so that they can finally retrofit the dam the next 10 years (any bets on it being longer and more expensive?), I don't expect the water situation there to get any better any time soon.
I was born & raised in the bay area, a rare local. When my dad moved into Belmont, just across the freeway from where Downtown Oracle is now.... the main drag Ralston Avenue was a dirt road out to Highway 101.
What has happened to this area is an economic and social tragedy not yet realized.