With recent reports indicating an increased threat of extreme weather related events and rising sea levels due to climate change, critical infrastructure is expected to become more threatened by water infiltration and flooding. For communication infrastructure, including data centers, it is critical to reduce the risk of downtime to maintain operational reliability. While site selection might offer the best protection, for some locations, data center hardening might be the only option. Adopting effective sealing designs of openings in data centers as a best practice could effectively mitigate risk and should be considered in data center hardening strategies.