Colorado Service of Process Rules
Colorado has several service of process rules. These are all included under the primary Colorado Rules of Civil Procedure, CRCP, Chapter 1. However, county courts (Chapter 25), probate courts (Chapter 27) and juvenile courts (Chapter 28) have their own procedures. In cases of conflict in the probate and juvenile courts, those courts’ rules control.
Lawyers, paralegals, and legal professionals should be sure when filing in any Colorado court that they are following the rules for that court. The differences between state and county court filings are not significant, but the differences between state and probate are considerable. Improper service of process can lead to a case being dismissed, or at a minimum costly delays in the proceeding.
Where to Find Colorado Service of Process Rules
Colorado's service of process rules are governed by the Colorado Rules of Civil Procedure (C.R.C.P.), which are maintained and published by the Colorado Judicial Branch.
Colorado service of process rules are not unusually complex, but they have been placed in multiple locations. As a result, lawyers and paralegals can be misled by all the copies of the rules online. The primary source is the official Colorado Rules of Civil Procedure, available through legal research platforms such as Lexis, Westlaw, and the Colorado Judicial Branch website. Law firms in Colorado should have their own copy along with local court rules and filing requirements of the judges in their courthouses.
Methods of Service
The plaintiff, that is, the person initiating the legal action, is responsible for delivering the summons and complaint to the named defendant(s) in the suit. Colorado rules allow several methods of service. Who receives service depends on the type of defendant. Service on individuals is different from service on companies or governments.
The summons and complaint are served under Colorado Rule of Civil Procedure 4. Except for service by publication or a court order providing otherwise, the complaint must accompany the summons. Colorado imposes a 63-day deadline to serve each defendant after filing the complaint.
Personal Service
Personal service under Rule 4 is done by hand-delivering a copy of the summons and complaint to the defendant. Service can also be made by leaving a copy at the person's usual place of abode with any person who is eighteen years or older and a member of the person's family, or at the person's usual workplace with certain individuals specified in Rule 4. It isn’t quite that easy, however. The person delivering the summons and complaint must be over the age of 18, and not a party to the action. They also need to know how to file a declaration of service afterward, and be able to testify in court that they followed all the rules. It may be best to use a professional process server who knows how to deliver the documents, the correct things to say, and the proper things to file after service is complete.
Once a case is underway, service of subsequent court documents on represented parties is governed separately by Rule 5, which has its own requirements.
Service on minors follows a nuanced process under Rule 4(e)(2). For a person between 13 and 18 years of age, a copy must be delivered to the person AND another copy to their parent or guardian; if no parent or guardian is in the state, then to any person in whose care or control they reside. For a person under 13, service is made to their parent, guardian, or caretaker.
Substituted Service
Sometimes, personal service is not possible. The defendant may know a lawsuit is coming and take steps to avoid the process server. The defendant’s work hours may just keep them from encountering the process server. For whatever reason, the server cannot make personal contact with the defendant. Under Rule 4(f), if personal service cannot be accomplished, the party may file a motion identifying the person to whom they wish to deliver process. The court may then authorize delivery to that person and order the process to be mailed to the address(es) of the party to be served. Service is complete on the date of delivery to the person authorized by the court.
The court's order will specify the mailing address(es). Many attorneys recommend using certified or registered mail so the plaintiff has a record.
Multiple Defendants
In a suit against an entity such as a corporation or a trust, the CRCP does not require serving every single member of the organization. Instead, process can be served upon the entity's registered agent or an authorized person designated to receive service of process for that type of entity.
Legal action against government entities is complicated and may require serving the attorney general, county counsel, or city clerk.
Other Methods of Service
For general civil matters, Colorado does not allow "nail-and-mail" service—the process server cannot simply leave the papers at the door and mail a copy to the defendant; any summons that is left must be left with someone at the residence. However, for eviction (FED) proceedings, posting and mailing is a permitted method of service after diligent attempts at personal service, per C.R.S.A. § 13-40-112. Colorado has specific requirements for service of process in eviction matters, and not only the summons and complaint but other documents relating to evictions must be included in the service packet.
Eviction (FED) Actions: Rule 3.1 and Amended Rule 4
Effective March 16, 2026, Colorado has made a significant change to how Forcible Entry and Detainer (FED) actions—eviction proceedings—must be initiated. Under the new Rule 3.1, FED actions can only be commenced by filing a complaint with the court. The court obtains jurisdiction at the time of filing. Previously, Colorado Rule 3 allowed civil actions to be commenced without distinction either by filing or by serving the defendant first, whichever came first. That flexibility no longer applies to FED cases.
Alongside Rule 3.1, Colorado has amended Rule 4 so that any summons issued pursuant to Rule 4 shall not be served on a defendant unless it includes the case number assigned by the court in the caption. The practical sequence for all Colorado eviction matters on or after March 16, 2026 is: file the complaint first, receive the case number from the court, then serve.
Law firms and property management companies handling Colorado evictions should review their intake workflows to confirm that service is not ordered or submitted before the complaint has been filed and a case number assigned. Firms that previously used a service-first approach for FED matters will need to update their templates and internal procedures accordingly.
Hybrid Service (Property Management)
Colorado property management firms should be aware that posting and mailing is a permitted service method in two contexts: (1) for pre-litigation notices like Demands for Compliance, through a method often called "hybrid service," and (2) for the summons and complaint in a Forcible Entry and Detainer (FED) suit itself, after diligent attempts at personal service (C.R.S.A. § 13-40-112).
In a hybrid serve, the process server first makes two personal service attempts within 96 hours (four days). If neither attempt is successful, the server may then post the documents—meaning they affix them to the door of the rental unit in a conspicuous manner. The server may also sub-serve to a co-resident or family member who is at least 15 years of age.
Timing matters here. The documents typically must be delivered or posted with enough lead time—often 10 days—to satisfy the notice period required before further legal action can proceed. Firms should work backward from the relevant cure or compliance deadline to ensure the service window is realistic.
It's worth distinguishing between the two contexts. Pre-litigation hybrid service is used to deliver compliance notices and similar documents to tenants before a case is filed. Once a Forcible Entry and Detainer complaint has been filed, the summons and complaint may be served by posting and mailing after diligent attempts at personal service, as permitted under C.R.S.A. § 13-40-112. Property management companies should maintain clear internal workflows to keep these two processes separate.
Other Methods of Service (continued)
For service of subsequent court documents (not the initial summons and complaint), electronic service is permitted if both parties have agreed to E-service in writing (Rule 5(b)(2)(D)). If the delivery does not go through for whatever reason, service has not been completed. As with other types of service, the plaintiff must ensure that the document was received by the defendant before service is complete.
If all other methods have been unavailing, the plaintiff can make a motion to the court for two other methods of service:
Service by mail. The court can order that service be made by certified or registered mail, to the defendant’s last known address. Service is complete on the date of the filing of proof of service, together with the return receipt attached and signed by the addressee. The proof of service is a sworn or unsworn declaration showing the date of the mailing with the return receipt attached.
Service by publication. When all else fails, publication of process can be ordered by the court in a newspaper published in the county where the action is pending. The notice must run once a week for five successive weeks. Service is complete the date of the last publication. Service by publication is most common in probate cases, but also divorce and other family law cases where the defendant is no longer in the state.
Colorado Proof Of Service
Once service of process is made, the person making it must file proof of service. Professional process servers have an appropriate proof of service form ready to complete and file with each document they serve. A proof of service may be sworn or unsworn, but must state the papers served, the name of the individual served, the date, time, and address of service, the manner of service, and facts showing the process server was authorized to do so.
If service is not completed within that 63-day window, the court may dismiss the case on its own initiative, or the plaintiff may move to dismiss.
