There's a few other factors and I'd be worried about the combination of them more than any single one. Depending in location and geography and timing you can ea

There's a few other factors and I'd be worried about the combination of them more than any single one. Depending in location and geography and timing you can easily lose a couple of feet by an exceptionally high tide, sea level is the average of high tide marks and not the highest it can get. Even in inland areas well above sea level this can affect drainage and cause flooding. Then you've got large waves that can be whipped up by a regular storm or a hurricane, these can easily go another couple of feet above the current tide level and just standing ankle deep in water like that isn't the safest thing in the world. Then there's things like rainwater flooding that can come from inland, depending on geography and rain that can be negligible or huge. But if the high tide and waves alone conspire then you might only have 6 feet of storm surge buffer. With an 18 inch sea level rise that's down to 4.5 feet. Even without that erosion can do a lot of damage without expensive remediation.