Housing in San Francisco is insanely expensive and has been for a long time. The state also gave homeowners a break in 1978 by holding property tax lower for people who held onto their homes but the value increased greatly- the tax increased as soon as the homes were sold.
From the link-
"The San Francisco housing market is very competitive. Homes in San Francisco receive 5 offers on average and sell in around 22 days. The median sale price of a home in San Francisco was $1.4M last month, up 1.2% since last year. The median sale price per square foot in San Francisco is ¤970, up 3.7% since last year."
The San Francisco, CA housing market is very competitive, scoring 73 out of 100. The average San Francisco house price was $1.41M last month, up 6.7% since last year.
www.redfin.com