Your answer was most helpful, the site I was refrencing was from marinwatersheds.org, which shows Novato as being in a special zone. Good news about your living here and loving it, hoping my family will too. Drainage pipes to keep water from collectimg under the house make sense, and maybe what I was seeing was these pipes before they were burried(?). I have been looking at houses all over Marin county, I have to say the strangest thing we saw was in San Rafael, where the homeowner put a pipe 50 feet into their backyard I assume to see the water table rising, too bad for all those homes and homeowners who have bought on fill and bay mud. With sea level rise, I would encourage anyone looking to buy to really look at the location, there are great sea level rise maps that show you what the bay area will look like with anywhere from 1meter rise to 50, it is very interesting, and worth researching. I believe its niave and extremely unprofessional for brokers and listing agents to not be completey forthcoming about these sorts of issues, for exaple, "special conditions" like flood zones etc, can be "unknown" to the listing agent and broker until you get the full disclosures, which can be very far into the process. I think its better to have full disclosure from the get go and for home buyers beware of sweet talking agents who insist they are "unaware" of any possible issues such as this.