I think I've found my next career: fire sprinkler vendor. I say this, because this seems to be a great career, since:

No matter. After finding only one fire sprinkler vendor on Craigslist, I resorted to the yellow pages(!). I came up with a list of a half-dozen in Marin, and contacted them. In addition, Chris Clark, my framer, provided the name of the guy who did his house.

What I've learned about sprinkler systems.

As stated above, Marin County requires them on any "substantial remodel." Another sheet defines substantial as 50+%. Since the foundation work is already impacting a third of the house, I know that I will quickly be over 50%. My natural tendency is to try to limit myself to 49%, and avoid this expensive requirement, but there's a real cost to having electricians, framers, sheetrockers, etc come out 12 months later just to stay below 50%.

The guy from Craigslist estimated that it would cost $4,500. Wow. That's low. At least compared to what I was imaging. So this made it easier to accept the requirement that I get sprinklered.

There's a proper order to installing services. It's a lot easier to work electrical around existing sprinklers, rather than work sprinklers around existing electrical. On a major remodel, where everything's been torn out, consider putting in ductwork first, then plumbing (including sprinklers), then electrical, including light cans.

The sprinkler vendor will need to know certain things about your existing water service in order to provide a total cost for the job. Unfortunately, the cost of upgrading your water service so that he/she has enough water pressure to work with may cost more than your sprinkler system!

Pressure at meter. This was in my home inspection report, and available via a quick phone call to my water utility. The pressure at my meter is 110psi. (My inspection report warned me about this high pressure and I spent a few hundred dollars having a pressure reduction valve installed! Oh well...)

Size/type of piping to your house. When the parking space was expanded, the 5/8" iron piping was in the way, and so replaced by 1" soft copper. Turns out that what was a wise upgrade, since the sprinkler service requires that. Unfortunately my house connection point is 25' above the street-side meter, and that complicates the calculation...

Location of house in relation to meter. It's all about water pressure. I may have a lot of pressure at the meter, but the pressure calculations will include where the house is in relationship to the meter, and the height of the house itself. My house connection point is 25 feet above the street-side meter, and I have a two-story home.

Size of water meter, and size of connection from the utility's main to your meter. This information is also available via a quick phone call to the local water utility. I learned that my meter is 5/8" and that the connection to my meter is 3/4". I've been given inconsistent information from sprinkler vendors re what size the meter will need to be (It's either 3/4" or 1"), and what size the connection to the meter will need to be (either 3/4" or 1"). This is where it can get expensive. Here in Mill Valley, the cost of upgrading to a 3/4" meter is a one-time charge of $179 and a monthly increase of $0.92. If a 1" meter is needed, I'm not sure what the one-time upgrade charge is, but my monthly bill increases by $4.58. But if I need to have the utility upgrade the main-to-my-meter connection from the current 3/4" to 1", I will be billed $3900. Ouch!

Fire Sprinkler Contractors I've Contacted:

Automatic Fire Safety (415-898-4448) I spoke with Miles. He wanted floor plans and site map. I didn't have everything at first, but did eventually email what was requested. I followed up, but have no record of hearing back from him.

Baswell Plumbing (415-897-7977) I was told that Jeff would get back to me. Never heard from him.

Dreier Fire Protection (415-883-1359) I got a machine the first time, then spoke with Heather, who explained that Theo was the expert, and that he would get back to me. Theo and I spoke, but he never made it out here.

Serano's Fire Protection (707-789-9940) Mario Serrano wins points for being the most responsive. He came out, and really seemed to know his stuff.

After a week or so, when I didn't get a quote, I followed-up. He told be that he had no interest, since he had "some big jobs right now."

Burkell Plumbing (P.O. Box 1384, Sausalito, CA 415-332-9018) Michael Burkell came out, and was also a wealth of information.

Billy Tyma at Fire Technologies (Mill Valley, 415-457-6805). After a half-dozen phone conversations and messages, Billy came out. Like the others, he seemed really sharp. He walked the house, shared thoughts, then told me it was best for him to get involved only AFTER the county had approved the plans. He guessed that it would cost ~$4,000.

With my plans approved, I re-contacted a few of the vendors.

Theo, from Drier's actually came out. After the visit he phoned me - saying that I might need to upgrade my 1" water service from the street (!).
Burkell's too busy.
Nothing from Billy Tyma. Jeez...

Weeks passed. I called Billy Tyma again. He came out, walked around, marking-up a set of plans, and left. He said that he could make it work with my existing 3/4" meter. He told me to finish getting all light cans in place. I phoned him a week later, asking status, and learned that he had submitted his plans to the County. He told me to give the County a week or two to review them.

The plans were approved. The installers came out, and completed the sprinkler install in two days.

Postscript: As mentioned above, Billy told me to get all my light cans in before his guys started. I'm thinking that this is a pretty classy way to put in sprinklers - let the homeowner put their lights where they want, then do whatever it takes to get the sprinklers right. So if you're shopping fire-sprinkler installers, I suggest that you listen to see if you are supposed to work your lights around their sprinkler plan, or if you get to put your lights where you want them.