When a customer refuses to pay a construction invoice, your most powerful collection tool is a mechanics lien — a legal claim against the property itself that can force payment or block a sale or refinance. Most states require subcontractors and suppliers to serve a preliminary notice early in the project (often within 20 days of first furnishing labor or materials) to preserve that lien right; missing that window can permanently eliminate your ability to lien the property. Beyond the lien, your escalation path runs: written payment demand → mechanics lien → small claims or civil court → collections. Each step has hard deadlines that vary by state. Acting fast matters — the longer an invoice sits unpaid, the fewer legal remedies remain available.
What Should You Do First When a Customer Isn't Paying?
Send a formal written payment demand immediately — not a text, not a voicemail, a written demand by email and certified mail. Before you call an attorney or threaten a lien, a clear demand letter resolves a surprising number of disputes, because it signals that you know your rights and are willing to enforce them.
Your demand letter should include:
- The exact amount owed, broken down by invoice number and date
- The project address and description of work performed
- Your contract reference (date signed, scope covered)
- A payment deadline — 10 to 14 days is standard and reasonable
- The consequences of non-payment: mechanics lien filing, referral to collections, or civil suit
Keep the tone professional, not threatening. You want payment, not a fight. Courts also look more favorably on contractors who documented a good-faith attempt to resolve before litigating.
Send it certified mail with return receipt requested so you have proof of delivery. This matters if you end up in court.
How Does a Mechanics Lien Help You Collect an Unpaid Construction Invoice?
A mechanics lien is a legal encumbrance placed on the property where you performed work — it attaches to the real estate, not just the person who owes you money. That means if the property owner tries to sell or refinance, your lien shows up in the title search and must be resolved first. It's one of the few collection tools that creates genuine urgency for the paying party.
Mechanics lien rights exist in all 50 states, but the rules — deadlines, notice requirements, filing procedures — differ significantly by state. The general sequence looks like this:
- Serve preliminary notice (required in most states, often within 20 days of first furnishing)
- File the mechanics lien with the county recorder after non-payment
- Enforce the lien by filing a lawsuit within the state's enforcement window (often 90 days to 1 year after filing)
If you skipped the preliminary notice because you didn't think you'd need it, your lien rights may already be impaired. That's the hard truth. Preliminary notices aren't just paperwork — they're the prerequisite to the lien itself.
According to data cited by Lienser via DocJoist's Construction Payment Statistics, preliminary notices were filed on construction projects valued at over $22.7 billion in the United States in 2024. Contractors who file them are in a fundamentally stronger position when disputes arise.
What Are the Deadlines for Filing a Mechanics Lien?
Lien filing deadlines depend entirely on your state and your role in the project. Missing them ends your lien rights — there is no extension.
Here are deadlines for several common states to illustrate the range:
- Florida: Subcontractors must serve a Notice to Owner within 45 days of first furnishing under Fla. Stat. § 713.06(2)(b). The lien itself must be recorded within 90 days of final furnishing under Fla. Stat. § 713.08(5).
- California: Subcontractors must serve a 20-day preliminary notice under Cal. Civ. Code § 8200. The mechanics lien must be recorded within 90 days of completion of the work of improvement, or 60 days after the owner records a Notice of Completion.
- Texas: Subcontractors without a direct contract with the owner must send a monthly written notice by the 15th day of the third month following each month in which unpaid labor or materials were furnished, under Tex. Prop. Code § 53.056. Texas lien filing is due by the 15th day of the fourth month after the last month of furnishing.
- Arizona: Preliminary 20-day notice is required under A.R.S. § 33-992.01. The lien must be filed within 120 days of the claimant's last furnishing date.
- Washington: A Notice of Right to Claim Lien must be provided within 60 days of first furnishing under RCW 60.04.031. The lien must be filed within 90 days of last furnishing.
These deadlines run from specific triggering events — first furnishing, last furnishing, project completion, or an owner-recorded notice. If you're unsure which deadline applies to your job, calculate it now before another day passes.
What Is a Construction Payment Demand Letter and How Do You Write One?
A construction payment demand letter is a formal written notice that you are owed a specific sum for completed work and that you intend to pursue legal remedies if payment is not received by a stated date. It is not a lien — it is the step before the lien, and it often resolves the dispute without going further.
A strong demand letter includes:
Header information:
- Your company name, license number, and contact information
- The recipient's name and project address
- The date of the letter
Body — keep it factual:
- "On [date], we entered into a contract to perform [scope of work] at [project address]."
- "Work was completed on [date] in accordance with the contract."
- "Invoice #[number] dated [date] in the amount of $[X] remains unpaid as of [today's date]."
- "Payment in full is due no later than [date 10-14 days out]."
Consequence clause:
- "Failure to remit payment by [date] will result in filing a mechanics lien against the property and/or pursuing collection through [small claims / civil court]."
Signature:
- Sign it, keep a copy, send it certified mail.
If the dispute involves more than $10,000–$15,000 (depending on your state's small claims limit), consider having an attorney review or co-sign the letter. Some attorneys offer a flat-fee demand letter service, which adds weight without committing you to full litigation costs.
When Should You Escalate to Legal Action?
Escalate when your demand letter goes unanswered after the stated deadline, when the customer disputes the debt in bad faith, or when the amount is large enough to justify the cost of court. The mechanics lien is your primary escalation tool, but it isn't your only one.
Your escalation options:
1. Mechanics Lien (most effective for real property) File immediately after the demand deadline passes — assuming you preserved lien rights. Do not wait. Lien deadlines are hard cutoffs.
2. Small Claims Court Each state has a dollar limit for small claims (ranging from $2,500 in some states to $25,000 in others). No attorney required in most jurisdictions. Filing fees are typically $30–$100. Use this for smaller invoices where a lien isn't practical.
3. Civil Court / Breach of Contract Lawsuit For larger amounts or complex disputes, a civil suit for breach of contract is the path. You'll want an attorney. Document everything: signed contract, change orders, invoices, communications, photos of completed work.
4. Collections Agency A last resort for accounts that are uncollectable through other means. Agencies typically take 25–50% of what they recover. Only use this after other remedies have failed or expired.
5. Contractor License Board Complaint In some states, filing a complaint with the state licensing board against a GC who refuses to pay a subcontractor can trigger regulatory pressure. It doesn't get you money directly, but it creates leverage.
The payment problem in construction is systemic. According to the Rabbet 2024 Construction Payments Report, 82% of contractors face payment waits of over 30 days, up from 49% just two years earlier. The same report estimates slow payments cost the U.S. construction industry $280 billion in 2024 — roughly 14% added to total construction spending. These numbers confirm that slow and disputed payments aren't bad luck; they're a structural feature of the industry that you need a systematic response to.
What Records Do You Need to Collect an Unpaid Construction Invoice?
You need documentation that proves three things: the work was agreed to, the work was done, and it hasn't been paid. Without these, collection through any channel becomes much harder.
Gather and organize:
- Signed contract or written agreement — even a text-message exchange confirming scope and price can help if no formal contract exists
- All invoices, including invoice number, date, amount, and description of work billed
- Change orders, signed if possible
- Proof of work completion — photos, inspection sign-offs, delivery receipts, daily logs
- All communications — emails, texts, voicemails; export and date-stamp them
- Lien notice documentation — proof of service for any preliminary notice filed (certificate of mailing, certified mail tracking)
- Payment history — any partial payments received, with dates
If you're heading toward a mechanics lien, the preliminary notice you filed — and proof you served it correctly — is critical documentation. A certificate of mailing from USPS or a signed return receipt card establishes a clear record that notice was properly delivered.
Can You Still File a Lien If You Didn't Send a Preliminary Notice?
In most states, no — at least not for work performed before the notice was served. The preliminary notice requirement is a strict statutory prerequisite to lien rights in the majority of states. Without it, the lien can be challenged and defeated by the property owner even if the debt is legitimate.
There are limited exceptions:
- Direct contracts with the property owner: In some states (including California under Cal. Civ. Code § 8200(b) and Florida under Fla. Stat. § 713.05), parties who contract directly with the owner may not be required to serve preliminary notice to preserve lien rights.
- Late service: In states like California, serving the preliminary notice late doesn't eliminate lien rights entirely — it limits protection to work performed in the 20 days before service. Some protection is better than none.
- Owner-occupied residential projects: Some states have different rules for residential versus commercial work.
The bottom line: if you're reading this after missing a preliminary notice deadline, consult a construction attorney in your state immediately. You may still have options — stop payment claims, breach of contract suits, bond claims on bonded projects — even if your lien rights are gone.
Frequently Asked Questions
How long does a contractor have to collect on an unpaid invoice?
The statute of limitations for breach of written contract claims typically runs 4 to 6 years in most states, but mechanics lien deadlines are much shorter — often 60 to 120 days from last furnishing for filing the lien, and 90 days to 1 year to enforce it. Do not confuse the two. Missing the lien deadline forces you into court without the leverage of a lien, which is a significantly weaker position.
Can a subcontractor lien a property if the GC — not the owner — owes the money?
Yes. Mechanics lien rights run with the property, not just the contractual chain. A subcontractor who was hired by the GC can typically lien the owner's property for work performed and not paid, provided the correct preliminary notices were served and lien deadlines are met. This is one of the most powerful features of mechanics lien law — your claim follows the real estate.
What happens after you file a mechanics lien?
Filing the lien creates a cloud on the property's title. The owner then has three practical options: pay you, negotiate a settlement, or wait for you to enforce the lien in court (which you must do within the state's enforcement window). Most liens result in payment or settlement before enforcement litigation begins, because the lien directly blocks the owner's ability to sell or refinance.
Does sending a demand letter reset any deadlines?
No. A demand letter does not pause, toll, or extend any lien filing deadlines. Lien deadlines run from statutory triggering events regardless of any correspondence between the parties. Continue pursuing the demand letter simultaneously with lien preparation — do not treat them as sequential steps if you're running short on time.
What if the customer claims the work was defective as a reason not to pay?
A defect claim does not automatically excuse non-payment, but it does create a disputed invoice that's harder to collect without litigation or negotiation. Document your work thoroughly — photos, inspection approvals, written acceptance. If the defect claim arises after you've already invoiced and been ignored for weeks, it may be a bad-faith tactic to delay payment. A construction attorney can advise whether the alleged defect is a legitimate offset or a pretextual dispute.
Is a verbal contract enforceable for construction work?
In most states, verbal contracts for construction work are legally enforceable, but they are extremely difficult to prove. If the contract value exceeds your state's threshold (many states require written contracts for projects over $500 to $1,000), the verbal agreement may not be enforceable at all. Always get it in writing. If you're currently in a dispute over a verbal agreement, gather every piece of indirect evidence: texts, emails, job site photos, supplier invoices for materials purchased for the job.
How does a mechanics lien affect the property owner's ability to sell?
A recorded mechanics lien appears on the property's title report, which title companies and lenders require to be cleared before closing. In practice, this means the owner cannot close a sale or complete a refinance until the lien is either paid off, bonded around, or successfully challenged in court. This is why liens create real collection leverage — they directly interfere with the owner's financial interests in the property.
What does it cost to file a mechanics lien?
County recording fees for a mechanics lien typically range from $15 to $100+ depending on the state and county. If you use an attorney to prepare and file, add $200 to $800 or more in professional fees. Preliminary notice filing through a service like LienFlash costs $24.99 per notice and includes attorney-reviewed forms and USPS Certified Mail — which is the prerequisite that makes the lien possible. The math is straightforward: the cost of preserving your rights is a fraction of the invoice amount at risk.
Protect Your Lien Rights Before the Deadline Passes
If a customer isn't paying and you haven't filed a preliminary notice yet, check your deadline right now. Every day that passes without action is a day closer to losing the most powerful collection tool available to you.
Use LienFlash to calculate your exact preliminary notice deadline based on your state and first-furnishing date, then file in about 2 minutes with attorney-reviewed forms delivered via USPS Certified Mail.