Secure data dissemination in wireless ad hoc and sensor networks has recently received a great deal of attention. A variety of protocols have been proposed in order to ensure secure data delivery across these systems; however, the majority, of these schemes assume the presence of public or pre-established symmetric keys. Accordingly, the cost of key management has not been incorporated into secure routing mechanisms in this setting. This paper considers the expenses incurred by sensor networks implementing secure routing schemes on top of probabilistic symmetric key management schemes. Specifically, we examine the overhead observed from proactive and reactive key establishment mechanisms for networks using a balanced method of key management. Through extensive simulation, we quantify more realistic costs for the application of secure hop-by-hop routing in sensor networks.