Yes - you need to place that lot on higher ground so it is above the top of the water table.
I often place basements using the basement tool on the beach and have them 4 levels deep with no water coming into them. But I've had others tell me they do get water in those basements too. I have noticed my sims splashing along as they walk sometimes when in one of those basements on the beach but there is no water visible. The sound effect when walking sounds like they are splashing in shallow water. I tend to ignore it if that happens - but it doesn't happen often.