AFAIK, tenting is the only EFFECTIVE means of getting rid of them. if you spot treat, you will not get them all and the colony is very likely to just move to another area of the house.

I have been told that I have drywood termites, too (I also live in Northern California). I have many concerns about using fumigation and am investigating alternative, non-chemical methods for eradication. One method I found that is as effective as fumigation is heating. The house is tented, though not as extensive as a fumigation, and then heated. The process takes 6-8 hours, so no move-out is required. You do have to remove candles, DVDs, CDs, plants, musical instruments (if practical), paintings, photographs, to be on the safe side. The house is heated to around 140 degrees F to ensure core temperature of the wood is heated to required temperatures. I'd be curious to see if anyone has used this method.

Heating was used on our house. Remember to open up that box in the back of the closet and make sure nothing meltable resides there. Now it's five years later and we had the house inspected, the inspector assures us he sees no active infestation. We did have a treatment done that forms a barrier under our pier and beam house, and if you go under the house for anything it probably breaks the barrier and has to be repeated. I think this treatment was in the form of a spray. Really the only big deal with the heat method is removing EVERYTHING that might have a problem with the heat. EVERYTHING. One thing they didn't mention was thin glass christmas bulbs, which became extremely brittle after this. Also recommend you find a way to remove musical instruments, even and especially pianos.