Not sure if you have seen this but here is the 2012 water quality report. Average pH was 8.5, so fairly basic. If you have a pH test kit/paper you can make a small batch of water + FP then add in the vinegar until you hit your desired pH. Then just scale up.

Also note that our water is treated w/chloramine not chlorine so you can't just dissipate it off overnight by setting the water out.

Ryan

Here is a link that might be useful: SF Water Report 2012

Get a pond/aquarium test kit for pH, the kind with liquid drops, not the piece of paper kind. The drop kind is quite accurate.

I use soil sulphur for my blueberries and hydrangeas, one application a year is easier than modifying the water.