I really dont know what else to do - my washing always smells like wee

As in my nappies that is.
I put my washing on a Heavy load (about a 2.5 hour cycle) with a pre-rinse and about 3 rinses at the end. And today, I even put it on an extra hot wash at the end and still . . . everything smells like wee

Its really bad if I have to put the washing in the dryer cause it makes the entire house smell.
I dont know what else to do - please help
