Google’s John Mueller said on Reddit that disallowing URLs with UTM parameters in them won’t help you to improve crawling or rating with Google Search. He added that a site should try to keep its internal URLs clean and consistent, but over time, the canonical tags should help with external links that carry UTM parameters on them.

John wrote, “I doubt you’d to see any visible effects in crawling or ranking from this. (And if there’s no value from doing it, why do it?)” When he was asked about disallowing such URLs.

He added:

This is all very similar to previous advice from John Mueller that I quoted in these stories:

John Mueller Of Google On 404ing or Using Rel Canonical On URL Parameters
Google: Tagging Internal Links With UTM Tracking Parameters Send Mixed Signals
Google: Do Not Use Robots.txt To Block Indexing Of URLs With Parameters

Forum discussion at Reddit.