@Fausto Carosella Every property is different. The artificial dam you are referring would not reduce premiums for most properties and could be expensive. ROI on some techniques like vents can be very good. I would recommend reaching out to a company called smartvent. They have a team called FRE that can review your your elevation certificates and insurance policies on a property by property basis to look for potential reductions. Our company will do this for free if you mention me and BP. You can then take the mitigation steps and get that insurance rate through us or your current provider.
@Anthony Lee To your point dry flood proofing is generally only used on commercial properties and there is a process. My point with all of this is that there are opportunities to save that people are not taking advantage of because they are unaware. Additionally flood proofing can be about protecting you property and not just premiums.