What happens to reports when a GA4 custom channel group is deleted?

Definition: A GA4 custom channel group is a set of channels that categorizes website traffic sources with rules. Google says deletion is irreversible; reports, audiences, and expanded datasets using the deleted group show the dimension as unavailable and require manual update.

Key facts

• Google's custom channel groups documentation supports a custom group as a primary dimension in reports that support the default channel group, such as Acquisition reports, and as a secondary dimension in default reports, such as the Events report.
• The same documentation makes custom channel groups available as dimensions in custom reports and explorations, and as conditions for audiences.
• Google says custom channel groups can be applied to reports retroactively.
• Google also says that a custom table containing the group can be deleted when the group is deleted.
• Google's Data API schema says custom channel group dimensions use the dimension scope and channel group ID, and the request fails when the property does not have a custom channel with that ID.

What changes in a saved report?

The deletion rule applies to every report that uses the deleted custom channel group as a dimension. Google's Help page describes the result as the dimension becoming unavailable and says the report requires a manual update. That covers a group used as a primary dimension in an Acquisition report and a group used as a secondary dimension in a default report such as Events.

Custom channel groups can also be dimensions in custom reports and explorations. The same deletion rule therefore matters beyond the standard report collection. Google documents retroactive application for custom channel groups, while the deletion section describes an unavailable dimension and a manual repair. It does not describe an automatic replacement with the default channel group.

What happens to custom tables and the primary group?

Google's documentation says that a Google Analytics 360 property may be prompted to create a custom table when a report is eligible and can benefit from one. When a custom channel group is deleted, the documentation says that you can also delete any custom table that contains that group. It presents table deletion as an additional action.

The primary channel group is the property's editable default channel group. Google says any custom channel group can be selected as the primary channel group in Admin under Channel groups, and that the selected group's criteria populate the primary channel group dimension on future reporting. The deletion section does not specify special handling when the group being deleted is the current primary group.

What should an API report owner update?

The Data API represents a custom channel group with a scope and an ID. Google's schema gives these generic API names:

sessionCustomChannelGroup:custom_channel_id
firstUserCustomChannelGroup:custom_channel_id
customChannelGroup:custom_channel_id

The first name describes the custom channel that led to a session, the second the custom channel that first acquired a user, and the third the custom channel that led to a key event. Google says the Metadata API can list the custom channel groups for a property. After deletion, a saved request that still names the removed group ID meets the documented condition under which the API request fails, so the request needs a manual update.

Related terms

• How do I create an AI assistants channel in GA4?
• Can a GA4 custom channel group classify historical visits?
• How do I make a custom channel group the primary group in GA4?
• Why does GA4 custom channel rule order affect AI traffic classification?

FAQ

Can a deleted custom channel group be restored?

No. Google describes custom channel group deletions as irreversible.

Does GA4 move the affected report to another channel group automatically?

Google documents an unavailable dimension and a required manual update. The deletion guidance does not describe an automatic move to the default or primary channel group.

Does deleting the group automatically delete a custom table?

The documentation says you can also delete a custom table that contains the group. It describes that as an additional action.

What happens to a Data API request that uses the deleted group?

Custom channel group dimensions include a channel group ID. Google says the request fails if the property does not have a custom channel with that ID.

Sources

1. Google Analytics Help, "Custom channel groups", undated
2. Google Analytics, "API dimensions and metrics", 13 October 2026

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