Since Highschool of the Dead is on Hiatus I'm trying to see if anyone knows of any good action/ survival horor zombie mangas.
Thanks. 😀

Well its not a manga but theres a comic called The Walking Dead that is exactly what you're looking for minus the ecchi 🙂 .
Its a great survival/horror comic, like much longer version of Dawn of the Dead with various locales.

I have six locks on my door all in a row. When I go out, I only lock every other one. I figure no matter how long somebody stands there picking the locks, they are always locking three.

P.S. Dead Fantasy. Look it up.

Tokyo Zombie, although it is a comedy.

Try these threads:
zombies
zombie manga