When you terminate an EC2 instance, AWS asks whether you want to delete the root EBS volume. The default answer used to be no, which means years of AWS usage have left a trail of orphaned volumes sitting in accounts across the world, each billing at $0.08 per GB per month.
A single 100GB orphaned volume costs $8 per month. Twenty of them, which is common in a team that has been deploying to AWS for two or three years, costs $160 per month. Across a year that is nearly $2,000 for storage that nobody is using.
The most common cause is the instance termination flow. When an engineer terminates an instance, they are focused on stopping the compute. The volume cleanup is an afterthought. In environments where instances are created and destroyed frequently, such as staging environments or CI/CD pipelines, volumes accumulate quickly.
Snapshots compound the problem. A volume that should have been deleted often has a snapshot taken of it first for backup purposes. The snapshot persists even after the volume is deleted, and snapshots are billed separately at $0.05 per GB per month.
The AWS default for new EC2 instances changed in 2021 to delete the root volume on termination. However, any instance created before this change or with a custom launch template may still use the old behavior.
In the AWS console, go to EC2, select Volumes from the left sidebar, and filter by state: available. Any volume with state available is not attached to any instance. It is a candidate for deletion.
Before deleting, check the volume's tags and any associated snapshots to confirm it is genuinely unused. Look at the creation date. A volume created three years ago with no recent snapshots and no meaningful tags is almost certainly orphaned.
The most effective prevention is changing the default termination behavior for new instances to delete the root volume on termination. This can be set at the launch template level or enforced via an AWS Config rule that flags instances where the volume is not set to delete on termination.
Tagging every volume with a purpose and owner at creation time also helps. A volume tagged with a project name and an owner email is much easier to evaluate than an untagged volume created two years ago.
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