Azure NAT Gateways are commonly deployed to provide outbound internet connectivity for resources within virtual network subnets. Over time, the workloads that originally required this outbound access may be scaled down, migrated, or decommissioned entirely. However, the NAT Gateway often remains attached to the subnet — continuing to incur hourly charges even when no active resources are using it. Because billing begins the moment the resource is created and continues for every hour it exists, an idle NAT Gateway generates a steady, fixed cost with zero functional return.

This waste pattern is particularly common in development, testing, and staging environments where infrastructure is provisioned for temporary workloads but networking components are not included in cleanup processes. NAT Gateways are subnet-level networking primitives, often provisioned by platform or infrastructure teams separately from the application teams that use them. This organizational separation creates gaps in ownership and cleanup responsibility, allowing idle gateways to persist unnoticed. Additionally, NAT Gateway has no stopped or paused state — the only way to stop billing is to delete the resource entirely. Even seemingly idle subnets can generate small data processing charges from background processes such as operating system updates or monitoring agents, which may create a misleading appearance of utilization and further delay cleanup.

The cost impact compounds when organizations maintain multiple idle NAT Gateways across subscriptions and environments. Each gateway also typically has an associated public IP address that incurs its own separate hourly charge, adding to the waste.