Gali, thanks for the link! Happily, Twikkii has never been a problem for me as all lots there were new and not "reused." Twikkii functioned beautifully so I never knew that beach front lots could not be reused. Whatever!
The one thing that annoys me to the Maxis is that EAxis, to the best of my knowledge and snooping, has never stated the lot anomalies for either UNI or BV. When I found that Bluewater was rich with beachfront availability, I plopped down my Three Lakes home in 6 places on one side and built a new lot (and reused it) on the other.
I was initially convinced (as we always advise here) that I had a hack that was causing the swimless problem...but how, as my game has been hack sanctioned okay for months?


? Oops, came here and discovered ShanOw's wise words. Now I am building again (and hating it so).
Diana, pre-BV I re-installed my games as we had bought a new PC; I had saved my old beloved houses as S2P's, added them back and had no problem, Well, one prob...a house that is in game and working fine after re-installation, crashed the next time I tried using it elsewhere for a different family [again, pre-BV]). There's no real explanation as the house does work fine with the original family. Three other old houses are working on different lots with no problems.
All of the old lots were placed before BV so I wonder if the "water" theory will prove a problem now that BV is installed? Time, and a future update, will tell!