I had a problem w/ water in mine also,but my drain plugs were plastic w/ no sealant on them.After being on water for several hrs. mine had water in them.I didn't think my truck was going to pull boat up ramp.Next day @ home I removed drain plugs & water ran out of each pontoon for several minutes.I put some pipe sealant on plugs,used it for several hrs. next time out,removed plugs ,no water.I would also suggest using aluminum,brass or plastic plugs.Steel in aluminum=problems.