It's illegal.
Your recourse is addressed in Section 92.008 of the Texas landlord tenant statute.
http://www.statutes.legis.state.tx.u.../htm/PR.92.htm
You'll have to sue him in small claims court for the money you are entitled to.
I agree with the suggestion that you just go turn it back on. If the landlord turned it off at the meter you might need one of these:
http://www.homedepot.com/s/water%252...2520key?NCNI-5

