Question from Reddit user:
We have a referring page and the url for our site has utm_source=.
I’m having a very hard time sussing out how to do this. Googling reveals a lot of results for how to report on a campaign or how to set up a tag. But nothing seems to show me just for this tag how much traffic are we getting.
Does anybody know a good site or video that explains that?
Answer from Nabil:
The short answer is:
You can absolutely create a report in GA4 to see traffic for a single specific utm_source value, like <oursourcetag>, and the easiest way to do this is by using the Traffic acquisition report and applying a filter.
You’ll navigate to Reports > Acquisition > Traffic acquisition, and then add a Filter to focus on the Session source dimension, setting it to exactly match <oursourcetag>.
The report will instantly update to show only the traffic, users, and engagement metrics associated with that single UTM tag.
For a fully customized visual breakdown over time, the optimal solution is to export the raw data using the Google Analytics Data API and build a dynamic dashboard in Looker Studio.
The long answer is:
It’s true that finding simple instructions for filtering by one specific UTM parameter can be tricky because most documentation covers the general setup or entire campaign reports.
To get straight to the traffic for your utm_source=<oursourcetag> in the standard GA4 interface, you want to use the Traffic acquisition report, as this report is structured around the user’s entire session and how they arrived at your site, which is the exact function of a UTM tag.
After you navigate to this report, look for the main table and find the All users segment filter at the top.
Next to it, click the Add filter button.
In the filter builder, you need to configure it to focus on the Session source dimension, which is the dimension GA4 uses to store the utm_source value.
You will select Session source as the dimension, set the matching type to exactly matches or contains, and then type in <oursourcetag> as the expression.
Once you click Apply, the entire report, including the time series chart and all the metrics, will immediately recalculate to show you only the traffic that came from that specific UTM source.
Alternatively, you can use a Free Form Exploration report, placing Session source as the Row dimension and adding a filter for Session source that exactly matches <oursourcetag>.
To create a more powerful and permanent solution that can track changes over time with advanced visualization, the best path is a custom data pipeline using the Google Analytics Data API to extract the data and the Looker Studio API to visualize it.
You would use the Data API to pull the raw traffic data using the date and sessionSource dimensions, applying a filter for your specific UTM source.
You then feed this data into Looker Studio via its API or connector, allowing you to build a dynamic, shareable dashboard that plots traffic from <oursourcetag> on a line chart over any desired time frame.
This approach is superior because the native GA4 reports are often subject to data sampling, and using the Data API circumvents this issue for most standard reporting queries.
If you have non-standard tagging needs or want to enrich the data before it hits GA4, employing Google Tag Manager and a server-side environment like Stape or Google Cloud Platform is an excellent solution.
This allows you to process, validate, or even append other attributes to the session_start event before it’s sent to GA4, ensuring the highest quality, most reliable UTM-related traffic data for reporting via the Data API.
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