The Walking Dead has one of the most dirty looking group of characters on television, and it always done very well in the ratings. Post-apocalyptic show done right.
Even the Walking Dead characters are only tv dirty, not dirty dirty. It's obvious with the women, their clothes are slightly dirty, their faces and hair? Not so much, I haven't seen a mop of greasy, sweaty hair on any female so far and they still seem to find the time to shave their body hair off. Don't expect to see a naturally hairy female leg or armpit, not even during the zombie apocalypse.