In my experience low rated (under 15k) stuff does not stand up to washing very well at all. Read: it washes out fucking immediately
Solution: don't wash it.
On the other hand my $400 gtx pants took about 10 washings over 300 days before they started to leak.
You shouldnt use regular detergent for the most part, unless its powdered, but I use nixwax, I've had the same bottle for like 5 years and its probably half full.