I live in Novato and I am very familiar with all areas in Novato and beyond. .
We had some major flooding in the early 1980s which mostly affected the San Marin valley and downtown areas. However, the City of Novato has since undergone some major projects to fix the drainage problem and issues surrounding Novato Creek. I have not heard of flooding of any major consequences for quite sometime now.
I am including a link to City of Novato Public Work Site http://ci.novato.ca.us/pw/eng/flood/flood.htm
for your reference. Although there is a pretty scary picture of flooding there, but that has not happened for many years.
Many areas in Novato are still located in what is designated as 100 year flood zone and you will have to obtain flood insurance if your house is within that area. On the flip side, due to the topography of Novato, many areas are also flood free.
Here is a link from City of Novato for the Flood Zone Map http://ci.novato.ca.us/pw/eng/flood/firm.htm
If you have question about a specific property, please feel free to give me a call or email me. I will be able to find that out for you â€“ on our tax records, there is a flood zone indicator which tells what kind of flood zone this property might be in (or not).
When you purchase a property, please do request a Natural Hazard Report (customarily paid by sellers), which tells you whether this specific property is in flood / earthquake / industry area, etc.