Effective January 1, 2010, a landlord cannot interrupt a tenant's utility service unless it is for bona fide repairs, construction or an emergency -- regardless of how the tenant pays for the utility service.  Even if the tenant is submetering the utility service from the landlord, and the tenant is behind on paying the bill, the landlord is prohibited from interrupting the utility service.  If the landlord provides the utility and is included in the rent, and the tenant is behind on the rent, the landlord is still prohibited from interfering with the utility.  Section 92.009, Property Code.

Even if the service is not in the tenant's name, the landlord cannot interfere unless it is for one of the reasons set forth above.  (If the bill is not in your name, it is a good idea to consider switching the bill to your own name as this is helpful in establishing credit, and might prevent a landlord from easily harassing you by calling the utility company and asking that "their service" be disconnected. While this would likely be illegal, it is better sometimes to prevent the problem from happening in the first place.)

If your utility service was disconnected by a landlord illegally, you have the right to request the justice court to immediately issue an order, called a writ of restoration, to require the landlord to reconnect the service.  You are also entitled to damages and civil penalties.  Section 92.0091, Property Code.

If the utility service has or is about to be shutoff because the landlord has failed to pay the utility company, then you have rights to take against the landlord, and you may be able to use your rent to avert any threatened cutoff. Section 92.301, Property Code.