Colorado Rules 3.1 and 4: What to Know Before March 16
Colorado is making a significant change to how Forcible Entry and Detainer (FED) actions must be initiated — and it takes effect March 16, 2026. If your firm handles eviction-related matters in Colorado, here's what you need to know to stay compliant.
What’s Changing?
Colorado is adding Rule 3.1 that will state that FED actions are commenced by filing a complaint with the court, and that the court obtains jurisdiction at the time of filing.
Respectively CO is also amending Rule 4 of its Rules of Civil Procedure to say that any summons issued in forcible entry and detainer cases shall not be served on a defendant unless it includes the case number assigned by the court in the caption.
Under the existing Colorado Rule 3, civil actions can generally be commenced either by filing with the court or by serving the defendant first — whichever comes first establishes jurisdiction. Rule 3.1 eliminates that flexibility for FED cases.
Starting March 16:
FED actions are commenced only by filing a complaint with the court
The court obtains jurisdiction at the time of filing
The "service-first" option is no longer available for FED matters
What This Means in Practice
The most immediate operational impact (from the Rule 4 amendment): in Colorado FED cases, the summons can’t be served unless the caption includes the court-assigned case number.
Rule 3.1 is what drives the workflow change: FED actions must be commenced by filing the complaint first, and the court obtains jurisdiction at the time of filing. Once you file, the court assigns a case number — which you’ll need on the summons before service can begin.
In short: for Colorado FED matters after March 16, you’ll need to file first, receive the case number, then serve.
What Your Firm Should Do
For any Colorado FED matters on or after March 16:
Ensure the complaint is filed with the court before submitting for service
Confirm the case number is present on the summons prior to service
Update any internal workflows or templates that assume service-first is an option for FED cases
How Proof Is Handling This
Tracking changes like this is part of what we do. Proof has a dedicated compliance function that monitors local rule changes across all jurisdictions we operate in — so our clients and the process servers on our platform stay ahead of requirements, not behind them.
For this change specifically, our operations team is actively working to update workflows for Colorado FED serves to reflect the new filing-first requirement. We're also working closely with our clients to make sure the transition is smooth.
Questions about how this affects your Colorado serves? Reach out to your account team or contact us at support@proofserve.com.
This article is provided for informational purposes and does not constitute legal advice. Rule changes can evolve — we recommend confirming current requirements with Colorado court resources or qualified legal counsel.
