California Surveyors Forums

I stole this info from a post at SurveyorConnect.com made by Jerry Penry...

"I have been working on this article for many years and feel it is something all surveyors should read who deal with vertical datums. Not all bench marks were on the 1929 or 1988 datums and many to this day still remain on their own isolated datums. Many bench marks were stamped with the elevation on the caps. Some by as much as 49 feet off."

http://www.amerisurv.com/PDF/TheAmerica ... ay2014.pdf

"This second link is to my own personal code list that I have developed. Please let me know if you ever come across one not on the list. As far as I know, USGS never published a list of codes, so this is unique and it will need to be updated as new information is found."

http://www.penryfamily.com/surveying/im ... delist.pdf

- See more at: http://beerleg.com/index.php?mode=threa ... GsXaV.dpuf"

Many cities in So Cal had their own datums loosely tied to the 1929, but since the late 50's cities have been eliminating their field crews and I think only a couple in OC still employ field surveyors.
As late as 10 years ago I encountered cities with BMs that they had no idea what they were based on, some were unaware that 29 and 88 datums existed.
Almost all in OC have changed to the County BMs and 88 datum, but there are holdouts such as Fullerton and Long Beach. Los Angeles city is slowly changing to 88 but not all bms at once. I think most BMs in Riverside and San Berdo counties have been slowly but surely destroyed.