Understanding Colorado’s Four-Month Rule for Filing a Mechanics' Lien
Every mechanic’s lien case in Colorado eventually runs into the same question: When was the last day you furnished labor or materials? Contractors often shrug and say, “Sometime in late March, I think.” Homeowners recall the date differently. And if the dispute ever reaches litigation, the court will focus intensely on that single point in time.
That’s because Colorado’s lien law imposes a strict deadline—commonly known as the four-month rule—for recording a mechanic’s lien. Miss the deadline by a day, and the claim evaporates. File too early or rely on punch-list work to push your deadline forward, and the lien may be challenged later as invalid.
This four-month window is where rights are preserved or lost, where payment leverage is created or forfeited, and where many lien disputes are won before they even begin.
To understand the rule, it helps to step back and see the lien statute as a timeline rather than a set of legal elements. If you’ve already read our Colorado Mechanic’s Lien Guide for Homeowners, you’ve seen the broader picture. This article narrows the focus to timing—specifically, what counts as “last work,” how courts interpret it, and why the four-month rule is one of the most consequential parts of Colorado’s mechanics lien framework.
Where the Four-Month Rule Comes From
Colorado’s lien deadline comes directly from statute. Under C.R.S. § 38-22-109(5), a contractor or subcontractor must record their lien within four months after the last day they furnished labor, materials, or equipment to the project.
Some parties mistakenly assume this means four months after the invoice date, four months after project abandonment, or four months after the final payment request. None of those interpretations align with the statute. Colorado ties the lien deadline to the actual improvement of the property, not paperwork or payment negotiations.
This rule is strict. Courts do not extend it based on equitable arguments, misunderstandings, or attempts to “revive” lien rights later. If the lien isn’t recorded within the statutory window, it cannot be enforced—even if payment is clearly owed.
What “Last Work” Really Means in Colorado
If you ask ten people on a construction site what “last work” means, you may get ten different answers. But Colorado courts use a more nuanced lens. What matters is whether the labor or materials furnished during that final visit contributed to the permanent improvement of the property.
Here’s what that means in practice:
Substantial completion counts. If a subcontractor finishes its scope—electrical rough-in, drywall installation, framing, roofing—the date of that substantial work is generally recognized.
Corrective work does not always count. Warranty repairs, punch-list touch-ups, or minor adjustments completed only to satisfy an inspection rarely extend the lien deadline.
Trivial work does not count at all. Something like tightening two screws, reconnecting a loose cover plate, or stopping by to look at a question does not give you a new deadline.
This distinction matters because contractors sometimes return to the property weeks after the real work is done, hoping to stretch the filing deadline. Courts rarely accept these attempts. A single screwdriver turn in mid-May will not revive a lien deadline that actually expired in April.
If you need an example of how strictly Colorado courts view compliance, our article Common Mistakes to Avoid When Filing a Mechanic’s Lien in Colorado dives into this issue and shows how even minor timing errors can unwind an otherwise legitimate claim.
Why Punch-List and Warranty Work Don’t Restart the Clock
One of the most common misunderstandings in Colorado mechanic’s lien disputes is the idea that any work, no matter how minor, extends the deadline.
But the four-month rule exists for a reason: to prevent stale claims and to give property owners certainty about the state of their title. If punch-list visits or warranty callbacks restarted the clock, a contractor could resurrect lien rights months or even years after substantial completion. Colorado courts have repeatedly rejected that idea.
Instead, the law draws a line between:
Work performed as part of the original contract, which can extend the deadline; and
Work performed simply to correct or adjust what has already been done, which does not.
Contractors who rely on post-completion visits to buy more time often find themselves with unenforceable liens—something that typically becomes clear only when the lien is challenged during litigation.
How This Deadline Plays Out in Real Disputes
From the homeowner’s perspective, this deadline offers clarity. Homeowners can track the project timeline, understand when lien rights are likely to expire, and make decisions about closing dates or refinancing with more confidence. If you're a homeowner worried about a potential lien, our Homeowner’s Guide to Colorado Mechanic’s Liens breaks down your rights in plain language.
From the contractor’s perspective, the deadline creates urgency. On most jobs, payment disputes do not magically resolve themselves. The four-month window forces contractors to decide whether to escalate the issue before the lien right disappears.
Many disputes settle during this period precisely because both sides recognize what is at stake. Once the deadline approaches, the conversation shifts from ongoing project issues to legal rights, title concerns, and risks of foreclosure.
The Four-Month Rule Is Only Part of the Timeline
Recording a lien within four months is only one step. After the lien is recorded, Colorado requires enforcement—typically through a foreclosure action—to occur within an additional statutory period, often six months from last work or project completion. If the contractor fails to take that next step, the lien expires.
This enforcement stage is where liens are tested. Property owners challenge whether the last work date was valid. Contractors point to documents, schedules, and field logs to establish substantial completion. And the courts decide whose timeline is correct.
For contractors preparing to enforce a lien, our article How to File a Mechanic’s Lien in Colorado contains a detailed explanation of the recording process and the steps that follow.
In Mechanic’s Lien Law, Timing Is Strategy
Whether you are the contractor asserting lien rights or the homeowner responding to them, everything in Colorado mechanic’s lien law revolves around timing.
The four-month rule forces clarity. It forces communication. It forces decisions that many parties would otherwise put off indefinitely. It is not just a deadline—it is part of the architecture of the statute, designed to balance the rights of contractors to secure payment with the rights of homeowners to have certainty about their property.
If you need help determining the last date of work, calculating your lien window, or evaluating whether a potential lien is valid, our firm regularly advises clients on both sides of these disputes across Colorado. And if you'd like a deeper overview of the entire process, don’t miss our Colorado Mechanic’s Lien Guide for Homeowners.
The information provided on this website is for general informational purposes only and should not be construed as legal advice or legal opinion. You should not act or refrain from acting on the basis of any information provided on this website without seeking legal advice from an attorney.