Real mom here. I bought for my 3yr old who still has occasional bed accidents although we haven’t tried it yet on the bed, I got a cup of warm water and layed the mattress cover on the floor as it would be on a bed and poured the warm water in a big puddle and thought for sure that amount of water would soak right through like all the other mattress protectors I’ve purchased in the past. IT WAS COMPLETELY DRY UNDER THE MATRESS PROCTECTOR.  The water didn’t pass through to the carpet and I even applied pressure for a few minutes as a child would if they had an accident in the middle of the night and it still didn’t pass through to the carpet. I love it so far. Now I’ll just have to test out the longevity of it but so far I’m impressed the water didn’t pass through. 4 stars since we just received it and haven’t tested it out long term.