This paper presents methodologies for deriving reliability performance of wireless communication networks to support demand response (DR) control. First, the impact of communication impairments on a direct DR control program is investigated. Second, the outage probability of a wireless link is modelled and quantified, considering the multipath fading, shadowing, and random path loss given the location distribution of smart meters. Third, the distributions of packet delivery ratio are derived for two wireless network architectures: the single-hop infrastructure-based network and the multi-hop mesh network. Simulation results verify the above reliability models and provide important insights on the coverage of wireless communication networks considering the reliability requirements of DR programs.