How to file a mechanics lien in Iowa

Step by step

14 steps for a subcontractor in Iowa.

1. 1

   Step 1: Work out which of Iowa's three tracks your job is on

   Before you start work, and again if the job description changes.

   Iowa does not have one lien process, it has three, and they share almost nothing. Residential means construction on single-family or two-family dwellings used or intended to be used mainly to live in, plus property under a chapter 499B horizontal property regime. Every other private job is commercial. Anything owned by the state, a city, a county, a school district or another public body is public works and cannot be liened at all.

   Where it goes

   No filing. This is a decision you make before you do anything else.

   How

   Read the job against the definition. A three-unit or larger apartment building is COMMERCIAL in Iowa, not residential, no matter how residential it looks.

   Proof to keep

   Your contract, the owner's name, and anything showing what the building is (permit, plans, unit count). If the job later turns out to be commercial, this is what shows why you read it the way you did.

   What the document must contain

   • Is the building a one- or two-family dwelling, or chapter 499B property? That is residential.
   • Is it private but not a one- or two-family dwelling? That is commercial.
   • Is the owner a government body? That is public works under chapter 573 — no lien exists.
   • Are you an architect, engineer or surveyor? Iowa's statute does not name design professionals and their lien standing is unsettled. Get Iowa legal advice before relying on any step below.

   If you miss it: You follow the wrong checklist and the mistake is usually fatal. Post residential MNLR notices on a triplex and you have done the wrong thing; skip the commercial 30-day notice to the general contractor on that same triplex and you have no lien at all.

   Iowa Code § 572.1(10) (residential construction defined); see also § 572.33(1) (commercial) and § 573.7(1) (public improvements)(opens the statute in a new tab)
2. 2

   Step 2: RESIDENTIAL subcontractor or supplier: check the registry for a Notice of Commencement, and post one yourself if it is missing

   Before you post your Preliminary Notice, which means before you start work. The ten-day deadline in section 572.13A does NOT apply to you — the Iowa Supreme Court held in 2022 that the ten-day limit binds contractors and owner-builders, not subcontractors stepping in for them.

   You cannot post your own Preliminary Notice until a Notice of Commencement already exists on the registry for that property. If the general contractor or owner-builder never posted one, you are allowed to post it yourself, and you post it together with your Preliminary Notice.

   Where it goes

   Iowa Secretary of State, Mechanics' Notice and Lien Registry.

   How

   Search the MNLR by property address, legal description or tax parcel number at https://sos.iowa.gov/mnlr/search . If nothing is there, post a Notice of Commencement yourself with the same information a general contractor would supply, then post your Preliminary Notice.

   Proof to keep

   Your dated search of the registry showing nothing was posted, plus the MNLR number and date-and-time stamp for the Notice of Commencement you posted.

   What the document must contain

   • The name and address of the owner
   • The name, address and telephone number of the general contractor or owner-builder
   • The address of the property or a description of its location
   • A legal description that adequately describes the property
   • The date work commenced
   • The tax parcel identification number

   If you miss it: You physically cannot post your Preliminary Notice, and without a Preliminary Notice you have no lien (§ 572.13B(4)). This is the trap that catches subs who wait: they go to comply, find no MNLR number exists, and have to build the whole chain from scratch.

   Iowa Code § 572.13A(2); Iowa Admin. Code r. 721—45.5(1)(b); Borst Bros. Constr., Inc. v. Finance of America Commercial, LLC, No. 20–0972 (Iowa June 17, 2022)(opens the statute in a new tab)
3. 3

   Step 3: RESIDENTIAL subcontractor or supplier: post your Preliminary Notice to the MNLR before you furnish anything

   Before you start work. Iowa sets no day count, so no date on a calendar protects you — only posting early does.

   This is the single most important thing you do on an Iowa residential job. There is no deadline in days — and that is exactly what makes it dangerous. Your lien is worth only the money the owner still owes the general contractor at the moment you post. Every payment the owner makes to the contractor shrinks your lien, and the day the owner pays the contractor in full your lien is worth nothing.

   Where it goes

   Iowa Secretary of State, Mechanics' Notice and Lien Registry, at https://sos.iowa.gov/mnlr/ .

   How

   Post it online at the MNLR ($7), or send it to the Secretary of State by U.S. mail, fax, personal delivery or courier delivery ($10). Post online if timing is tight: a mailed or faxed notice is stamped when the office posts it, up to three business days after they receive it.

   Proof to keep

   The MNLR posting record with its date-and-time stamp, your payment receipt, and the proof of service the Secretary of State posts showing the owner notice was mailed — you can download it from the registry under the MNLR number.

   What the document must contain

   • The name of the owner
   • The MNLR number for the property
   • Your name, address and telephone number
   • The name and address of the person who actually hired you
   • The name of the general contractor or owner-builder you are working under
   • The address of the property, or a description of its location if it has no usable address
   • A legal description that adequately describes the property
   • The date you first furnished material or first performed labor
   • The tax parcel identification number
   • The county or counties the property sits in
   • Your email address, or the email of whoever should receive registry correspondence

   If you miss it: No lien at all. Section 572.13B(4) says a subcontractor who fails to post a preliminary notice 'shall not be entitled to a lien and remedy provided under this chapter.' And short of missing it entirely, every day you delay cuts the lien down to whatever the owner still owes the contractor.

   Iowa Code § 572.13B(1), (3)(a), (4), (5); fees at Iowa Admin. Code r. 721—45.13(1)(b); contents also at r. 721—45.5(2)(opens the statute in a new tab)
4. 4

   Step 4: RESIDENTIAL subcontractor or supplier: send the owner your own copy and keep the receipt

   The same day you post the Preliminary Notice. The earlier the owner receives it, the more your lien is worth.

   The registry mails an owner notice for you when you post, but if you ever have to enforce the lien, the burden is on YOU to prove the owner actually received notice — and your lien is capped a second time at whatever the owner still owed the contractor on the day the owner actually received it. Sending your own copy is how you fix the date and prove it.

   Where it goes

   To the owner, at the owner's address. Note that owner-builders are never sent the registry's owner notice — if you are working under an owner-builder, sending your own copy is the only notice that happens.

   How

   Any of three ways the statute names: certified mail with return receipt; personal service in the manner original notices are served; or actual delivery with a signed receipt from the owner. If you provide an affidavit of mailing, the owner is presumed to have received it on the fourth business day after it was sent, and the burden shifts to the owner to disprove that.

   Proof to keep

   The green certified-mail return receipt, the process server's return, or the owner's signed acknowledgment — and your affidavit of mailing if you rely on the four-business-day presumption. This is the document that decides how much your lien is worth.

   What the document must contain

   • A copy of the Preliminary Notice you posted
   • The MNLR number

   If you miss it: You can still have a valid lien, but in court you carry the burden of proving the owner got notice, and you may be unable to establish the date that fixes the balance-due cap. In practice that can reduce the lien toward zero.

   Iowa Code § 572.13B(2), (3)(a), (3)(b); Iowa Admin. Code r. 721—45.5(3), 45.5(4)(opens the statute in a new tab)
5. 5

   Step 5: COMMERCIAL, second tier only: send the general contractor a one-time written notice within 30 days of first furnishing

   Within thirty days of the first day you furnished labor or materials for which you may claim a lien. It is one time only — everything you later furnish to the same subcontractor on the same project is covered by that one notice. Iowa has no monthly or repeating notice.

   On commercial jobs Iowa has no registry preliminary notice. There is exactly one preliminary requirement, and it binds only people who furnished labor or materials TO A SUBCONTRACTOR. If you contracted directly with the general contractor, the owner-builder or the owner, you owe nothing here. If you were hired by a sub, this notice is a condition of your lien.

   Where it goes

   To the general contractor, or to the owner-builder if there is no general contractor.

   How

   In writing, sent directly to the general contractor or owner-builder. This is NOT posted to the MNLR, and the Secretary of State does not accept commercial preliminary notices.

   Proof to keep

   Certified mail return receipt or another delivery record, plus a copy of the notice. You will need this twice: once to prove you sent it, and again because when you post the lien you must support it with a certified statement that this notice was given.

   What the document must contain

   • Your name
   • Your mailing address
   • Your telephone number
   • The name of the subcontractor you furnished the labor or materials to

   If you miss it: No lien. Section 572.33(2) says a person furnishing labor or materials to a subcontractor 'shall not be entitled to a lien' unless they both give this notice within thirty days and support the lien claim with a certified statement that it was given.

   Iowa Code § 572.33(1), (2)(a), (2)(b)(opens the statute in a new tab)
6. 6

   Step 6: PUBLIC WORKS, second tier only: send the principal contractor a one-time written notice within 30 days of first furnishing

   Within thirty days of first performing the labor or furnishing the materials, service or transportation. One time only — later work to the same subcontractor on the same project is covered by the same notice.

   The public-works mirror of the commercial rule. If you performed labor or furnished materials, service or transportation TO A SUBCONTRACTOR on a public job, you must notify the principal contractor or you have no claim against the retainage or the bond. If you contracted directly with the principal contractor, you owe nothing here.

   Where it goes

   To the principal contractor on the public improvement.

   How

   In writing, to the principal contractor. This requirement does not apply at all to highway, bridge or culvert projects.

   Proof to keep

   Certified mail return receipt or equivalent delivery proof, and a copy of the notice — you must support the claim with a certified statement that the principal contractor received it.

   What the document must contain

   • Your name
   • Your mailing address
   • Your telephone number
   • The name of the subcontractor you performed the labor for or furnished the materials, service or transportation to

   If you miss it: You are not entitled to a claim against the retainage or the bond under chapter 573. There is no lien to fall back on, because public property cannot be liened.

   Iowa Code § 573.15(1)(a), (1)(b), (2)(opens the statute in a new tab)
7. 7

   Step 7: RESIDENTIAL, on a job running past two years: renew your registry posting before it goes inactive

   Within the 60 days before the two-year anniversary of posting. That is the only window the rule gives you.

   MNLR postings expire. A Preliminary Notice that has been sitting on the registry for two years is declared inactive unless it is renewed, and a Notice of Commencement with no active postings attached to it goes inactive two years from posting. Since no preliminary notice means no lien, letting it lapse can quietly end your lien rights on a long job.

   Where it goes

   Iowa Secretary of State, Mechanics' Notice and Lien Registry.

   How

   Renew it on the MNLR.

   Proof to keep

   The renewal confirmation with its date-and-time stamp.

   What the document must contain

   • The MNLR number for the property

   If you miss it: Your notice is declared inactive and is removed from the registry one year later. Because section 572.13B(4) conditions the lien on having posted a preliminary notice, a residential subcontractor on a multi-year project can lose lien rights simply by letting the posting go stale.

   Iowa Code § 572.34(12); Iowa Admin. Code r. 721—45.4(4), (5), (6), 45.5(5), (6), (7)(opens the statute in a new tab)
8. 8

   Step 8: RESIDENTIAL, when payment stops: send the contractor a written notice of nonpayment

   Optional

   Before you commence that action, once the contractor has failed to pay you.

   A separate remedy that runs against the general contractor or owner-builder personally, not against the property. On residential work a contractor who has been paid in full by the owner must pay you within thirty days. If it does not, you can sue for the amount due, and the court must add exemplary damages of between one and fifteen percent — but only if you sent this notice first.

   Where it goes

   To the general contractor or owner-builder that was paid for the improvement.

   How

   In writing, delivered in a reasonable manner.

   Proof to keep

   A copy of the notice and proof of how and when you delivered it.

   What the document must contain

   • Terms that reasonably identify the real estate that was improved
   • The nonpayment you are complaining about

   If you miss it: You cannot bring the section 572.30 action. Be aware the contractor can also defeat the exemplary damages by posting a bond within fifteen days of receiving your notice, or by showing it applied all the money it received to the cost of labor and materials for the improvement.

   Iowa Code § 572.30(opens the statute in a new tab)
9. 9

   Step 9: Post your mechanic's lien to the MNLR within 90 days of YOUR last day on the job

   Within 90 days after the date you last furnished material or last performed labor. On a lien against a railway the clock is different — a subcontractor gets 90 days from the last day of the MONTH in which the labor was done or material furnished.

   This is the main event on any private job, residential or commercial, and the deadline is the same for a general contractor and for the most remote supplier. Ninety days is measured from the last day YOU furnished material or performed labor — not from when the project finished. Post inside 90 days and the owner owes you the full value of your work even if the owner already paid the general contractor, and your lien is superior to other liens except those recorded before your work started. Miss 90 days and the lien is worth far less (see the next step).

   Where it goes

   Iowa Secretary of State, Mechanics' Notice and Lien Registry, at https://sos.iowa.gov/mnlr/ . Never the county recorder — liens have been posted to the state registry since 2013.

   How

   Post it online at the MNLR ($30) or mail it to the Secretary of State on the office's cover-page form ($40 — residential form MLR, commercial form MLC). Liens can only be filed electronically or by U.S. mail, and a mailed lien is date-stamped when the office posts it, up to three business days after receipt. It must be a verified statement of account, certified under penalty of perjury — Iowa does NOT require notarization and the official forms have no notary block. Paper attachments must be 8½ by 11.

   Proof to keep

   The MNLR number, the date-and-time stamp, the payment receipt, and a complete copy of everything posted including the itemized statement of account and the legal description attachment.

   What the document must contain

   • A verified statement of account of what you are owed, after allowing all credits
   • The date material was first furnished or labor first performed, and the date the last of it was furnished or performed
   • A legal description that adequately describes the property to be charged
   • The name and last known mailing address of the owner
   • The address of the property, or a description of its location if it has no usable address
   • The tax parcel identification number
   • The amount claimed
   • On commercial property only: register as an MNLR user and also supply the owner's name and mailing address, the general contractor's or owner-builder's name, address and telephone number, the county or counties involved, and an email address for registry correspondence
   • If you are a second-tier claimant on commercial work: a certified statement that you gave the general contractor or owner-builder the 30-day one-time written notice
   • Your certification under penalty of perjury that it is true and correct

   If you miss it: The lien is not dead, but it is badly weakened. After day 90 the owner's payments to the general contractor defeat you, good-faith purchasers and encumbrancers beat you, and you must take the extra steps in the next step. Note also that the registry can REFUSE an incomplete posting — a refusal on day 89 is a missed deadline, not a clerical hiccup.

   Iowa Code § 572.8 (what to post and the verification); §§ 572.14 and 572.18(1), (3) (why 90 days is the real line); § 572.12 (railway); § 572.34(6), (8) (fee cap and filing methods); fees at Iowa Admin. Code r. 721—45.13(1)(c); refusal grounds at r. 721—45.14(opens the statute in a new tab)
10. 10

    Step 10: If you are already past 90 days: the limited late lien, and the wall at 2 years and 90 days

    Optional

    Up to two years and ninety days after the date you last furnished material or performed labor. Do not plan around this: that same day is also the last day to file suit, so a lien posted near the limit is unenforceable the moment it exists.

    Iowa does not slam the door at day 91. A general contractor or subcontractor can still post a lien up to two years and ninety days after last furnishing — but it is a weaker instrument. You must also give the owner written notice, the lien is enforceable only up to whatever the owner still owed the general contractor when that notice was served, and anyone who bought the property or took a mortgage in good faith without notice of your lien beats you.

    Where it goes

    The lien goes to the Mechanics' Notice and Lien Registry; the written notice goes to the owner.

    How

    Post the lien to the MNLR as usual, AND give written notice of it to the owner. That notice may be served by any person in the manner original notices are required to be served. If the person to be served is outside the county where the property sits, a return of that fact is sufficient service from the time the lien was posted.

    Proof to keep

    The MNLR posting record, and the server's return or other proof of exactly WHEN the owner was served — that date fixes how much your lien is worth.

    What the document must contain

    • Everything the ordinary lien requires under § 572.8
    • Separate written notice to the owner that the lien has been posted
    • Service of that notice in the manner original notices are served

    If you miss it: After two years and ninety days from last furnishing you cannot post the lien at all. And because a lien must be perfected before you can sue on it, and the suit deadline falls on that same day, waiting that long leaves you with nothing to enforce.

    Iowa Code §§ 572.9, 572.10, 572.11; § 572.18(3)(opens the statute in a new tab)
11. 11

    Step 11: PUBLIC WORKS: file a sworn itemized claim with the public body — there is no lien

    At any time before 30 days after completion and final acceptance of the improvement. Three things can move that date earlier than you expect: if the public body releases retained funds at 95% completion, the 30 days runs from the 95% date instead; if the contractor abandons the job or is legally excluded, the improvement is deemed complete on the date the contract was officially cancelled; and a contractor can request early release of retainage after substantial completion on only ten calendar days' notice to you. You may still file after the 30 days if the public body has not paid the full contract price and no action is pending — but by then the money may be gone.

    Public property cannot be liened in Iowa. Instead you file a claim against the retainage the public body is holding and against the contractor's payment bond. It is a different document, a different office and a much shorter clock than a mechanic's lien.

    Where it goes

    With the officer, board or commission authorized by law to let the contract. For county highway improvements, the county auditor of the county that let the contract. For farm-to-market highway contracts paid from farm-to-market funds, the auditor of the Iowa Department of Transportation.

    How

    An itemized, sworn, written statement of your claim.

    Proof to keep

    The officer's endorsement showing the time of filing, plus your copy of the sworn claim. Also keep the ten-day early-release notice if the contractor ever sends you one — it tells you the retainage is about to be paid out.

    What the document must contain

    • An itemized statement of the labor, material, service or transportation you furnished
    • The amount claimed
    • Your sworn signature — this one genuinely must be sworn, unlike a mechanic's lien

    If you miss it: You lose your place in the retained fund. A person who furnished ONLY materials to a subcontractor who was itself furnishing only materials has no claim against the retainage or the bond at all, and never did.

    Iowa Code § 573.7(1), (2); § 573.8(1); § 573.10(1), (2); see also §§ 573.15A(1), 573.23, 573.28(2)(opens the statute in a new tab)
12. 12

    Step 12: Sue to enforce the lien — the clock runs from last furnishing, not from filing

    Within two years from the expiration of the ninety days after the date you last furnished material or performed labor. In plain terms: 90 days plus 2 years from your last day, which is roughly 820 days.

    Posting the lien does not collect the money. You must bring an action in equity to foreclose it, and the deadline does not care when you posted. It runs from your last day on the job.

    Where it goes

    The district court in the county where the property, or some part of it, is situated.

    How

    By equitable proceedings in district court. No other cause of action may be joined with it. The lien must already be perfected before the action is commenced.

    Proof to keep

    The file-stamped petition showing the date of commencement, and your MNLR posting record.

    What the document must contain

    • A perfected lien, already posted to the MNLR
    • An equitable foreclosure action naming the property

    If you miss it: The lien is unenforceable. Note the collision: the last day to POST a lien under section 572.9 and the last day to SUE on it under section 572.27 are the same calendar date, so there is no scenario where the full two-years-and-ninety-days posting window leaves you time to litigate.

    Iowa Code § 572.27; § 572.24(1); § 572.25; § 572.26(opens the statute in a new tab)
13. 13

    Step 13: Watch the mail: the owner can cut your enforcement window to 30 days

    Thirty days from the day the demand is served on you. Not thirty business days.

    This is the lever most contractors never see coming. At any time the owner can serve you with a written demand requiring you to commence an action to enforce the lien. That demand overrides the two-year clock entirely.

    Where it goes

    District court in the county where the property is located.

    How

    You must actually commence the enforcement action in district court within those thirty days. There is no extension and no cure.

    Proof to keep

    The demand itself with the date you received it, and the file-stamped petition. Diary the 30-day date the moment anything that looks like this arrives.

    What the document must contain

    • A filed petition to foreclose the lien, commenced within 30 days of service of the demand

    If you miss it: The statute is blunt: the lien 'and all benefits derived therefrom shall be forfeited.' The owner can then post a copy of the demand with proofs of service to the registry, which is constructive notice to everyone that your lien is forfeited and cancelled. On public works there is an equivalent — the contractor can serve the same kind of demand and you have thirty days, or the retained funds are released to the contractor.

    Iowa Code § 572.28(1), (2); public works equivalent at § 573.16(2); Iowa Admin. Code r. 721—45.7(2)(opens the statute in a new tab)
14. 14

    Step 14: PUBLIC WORKS: sue only in the window between day 30 and day 60

    At any time after the expiration of thirty days, and not later than sixty days, following completion and final acceptance of the improvement. If the public body released retainage at 95% completion, the same window runs off the 95% date instead of final acceptance.

    Chapter 573 gives you a narrow window, not a deadline. You cannot sue too early and you cannot sue late. It is thirty days wide.

    Where it goes

    District court in the county where the public improvement is located.

    How

    An action in equity to adjudicate all rights to the retained fund or to enforce liability on the bond.

    Proof to keep

    The file-stamped petition, your filed claim, and the endorsement of the time your claim was filed.

    What the document must contain

    • A claim already filed with the public officer, board or commission
    • The officer or board that let the contract, the principal contractor, all claimants who filed claims, and the surety on the bond must all be joined as plaintiffs or defendants

    If you miss it: You lose the right to have the court adjudicate your claim to the fund. Filing before day 30 is just as ineffective as filing after day 60.

    Iowa Code § 573.16(1); § 573.17; § 573.15A(3)(opens the statute in a new tab)

Who can claim a lien in Iowa

Where you file

Office

Iowa Secretary of State — Mechanics' Notice and Lien Registry (MNLR)

Recording fee

$30–$40

Notarization

Not required

Sworn or verified

Verified statement of account certified under penalty of perjury

How it is served

Electronic filing

Copies

1

Fees and office procedures change; confirm them with the recording office before you file.

What trips people up in Iowa

• Assuming that because you contract directly with the owner you owe no notices. On a residential job the general contractor carries TWO independent forfeiture conditions before anyone is even unpaid: the boldface owner notice under § 572.13 and the MNLR Notice of Commencement under § 572.13A. Miss either and you have no lien at all. This is the opposite of the rule in most states and it is the most expensive mistake in Iowa.
• Treating the residential Preliminary Notice as something with a deadline you can work back from. There is no day count. The lien is capped at the balance the owner still owes the general contractor when you post AND when the owner receives it, so it decays on its own and hits zero the day the owner pays the contractor in full. Software that shows a future 'due date' here is telling you that you still have time while your recovery is already going to zero.
• Running the residential Notice of Commencement off your own first day. The ten days run from commencement of work on the PROPERTY, by anyone — a surveyor, an excavator, another trade. Post on day one regardless, because the notice only covers work furnished after it is posted.
• Reading 'residential' the way a normal person would. In Iowa it means one- and two-family dwellings only, plus chapter 499B property. A triplex is COMMERCIAL. Follow the residential registry procedure on a triplex and you did the wrong thing; skip the commercial 30-day notice on it and you forfeited the lien.
• Getting the commercial 30-day notice tier backwards. It binds ONLY people who furnished to a subcontractor. A first-tier sub or supplier dealing straight with the general contractor owes nothing. Applying it to everyone creates false alarms; applying it to no one destroys second-tier suppliers.
• Sending the commercial 30-day notice to the registry. It is not an MNLR posting — it goes in writing to the general contractor, and the Secretary of State does not accept commercial preliminary notices.
• Forgetting that the commercial notice has a second half. You must also support the lien claim with a certified statement that the notice was given (§ 572.33(2)(b)). Sending the notice and then not certifying it is a complete defense.
• Reading 'two years and ninety days' as a filing plan. After day 90 the lien needs separate written notice to the owner, shrinks to the owner-to-contractor balance as of that service, and loses to good-faith purchasers and encumbrancers. Treat 90 days as the deadline.
• Not realising that the last day to POST the lien (§ 572.9) and the last day to SUE on it (§ 572.27) are the same calendar date. A lien posted near that limit is unenforceable on arrival, because a lien must be perfected before the action can be commenced.
• Believing the lien is dead at day 91. It is not — a limited late lien is still available for roughly another 700 days. Contractors abandon real money here because they were told the window closed.
• Measuring the 90 days from project completion. It runs from YOUR own last day furnishing material or performing labor.
• Ignoring a letter from the owner demanding that you commence action. That letter replaces your two-year clock with thirty days and forfeits the lien and all benefits derived from it if you miss it. It never touches any software, so nothing will warn you.
• Leaving out the tax parcel identification number or an adequate legal description. Both are statutory content elements and the registry may refuse an incomplete posting. A refusal on day 89 is a missed deadline.
• Mailing the lien close to the deadline. The date-and-time stamp for a mailed lien is when the office posts it — up to three business days after receipt — not when you mailed it. Post online if you are anywhere near 90 days.
• Assuming you can add a county later. On residential work the lien reaches only the counties identified on the registry at the time the Notice of Commencement and Preliminary Notice were posted, not the counties listed on the lien itself.
• Letting a registry posting go stale on a long job. A Preliminary Notice or Notice of Commencement is declared inactive two years after posting unless renewed, and renewal is only possible in the 60 days before it lapses.
• Treating a school, city, county or DOT job like a private one. Public property cannot be liened. The real deadlines are a sworn claim with the contracting public officer within 30 days of completion and final acceptance, and suit between day 30 and day 60 — and both can move earlier if retainage is released at 95% completion, if the contract is cancelled, or if the contractor requests early release on ten days' notice.
• Assuming every supplier has a public-works remedy. A person furnishing only materials to a subcontractor who is itself furnishing only materials has no claim against the retainage or the bond at all.
• Notarizing the lien because a lien-service guide said to. Iowa requires a VERIFIED statement of account certified under penalty of perjury. The word 'notary' appears nowhere in chapter 572 or in the administrative rules, and the Secretary of State's own forms have no notary block. Public works is different — that claim genuinely must be sworn.
• Filing at the county recorder. Since 2013 every notice and lien goes to the statewide Mechanics' Notice and Lien Registry at the Secretary of State.
• Using the ordinary last-furnishing clock on a railway. A subcontractor claiming a lien on a railway gets 90 days from the last day of the MONTH in which the labor was done or material furnished — a different and later clock than anything else in the chapter.
• Filing one blanket lien against a condominium or cooperative building. Against a unit buyer who acquired in good faith and for value, the lien is unenforceable unless a lien statement specifically describing that unit was posted, timed from the last work on THAT unit.
• Posting a residential lien you cannot fully support. If the court finds a residential lien was posted in bad faith or the supporting affidavit was materially false, it SHALL award the owner attorney fees plus the lesser of $500 or the lien amount.
• Assuming a homestead is off limits. Iowa expressly makes the homestead salable to satisfy a chapter 572 mechanic's lien, including the attorney fees allowed by § 572.32(1).
• Thinking an owner-builder is an owner for notice purposes. Anyone hired by an owner-builder is a 'subcontractor', owner-builders get no lien of their own, and the registry never sends owner notices to owner-builders — so if you are working under one, your own mailed copy is the only notice that happens.

After you file

• The Secretary of State mails a copy of your lien to the owner once you post it. If the lien runs more than one page, the office may omit pages that are purely accounting and attach a note saying those pages can be inspected on the registry (§ 572.8(2)).
• Your enforcement clock did not restart. It still runs two years from the expiration of the 90 days after your last day on the job, no matter when you posted (§ 572.27).
• You may reduce the amount demanded through the registry without leave of court, and that does not affect the lien's priority. You may NOT increase it, and any other amendment needs leave of court in furtherance of justice (§ 572.26(2)).
• The other side can bond the lien off at any time by submitting a bond to the Secretary of State in twice the amount claimed. Your claim then runs against the bond instead of the property (§ 572.15; Iowa Admin. Code r. 721—45.8).
• Watch for the owner's written demand to commence action. It gives you thirty days to sue or the lien and all benefits derived from it are forfeited, and the owner can post the demand with proofs of service to the registry as constructive notice of the cancellation (§ 572.28).
• Priority is fixed by when your work started, not by when you posted. A lien posted within 90 days is superior to other liens except those of record before your work commenced — but a construction mortgage recorded before you started your particular work beats you (§ 572.18(1), (2)).
• On a residential job, keep renewing your registry posting if the project runs long. Two years after posting it is declared inactive unless renewed, and removed a year after that (§ 572.34(12)).
• When you get paid, you must acknowledge satisfaction. If you neglect to do so for thirty days after a written demand is personally served on you, you forfeit and pay $25 to the owner, general contractor or owner-builder, and you are liable to anyone injured to the extent of the injury (§ 572.23).
• A prevailing plaintiff in a lien foreclosure may be awarded reasonable attorney fees. But on residential property, if you lose a challenge the court may award the owner attorney fees and actual damages, and if the lien was posted in bad faith or the affidavit was materially false the award is mandatory (§ 572.32).
• On public works, filing the claim only freezes the retained percentage — it does not stop other payments to the contractor, and the fund may be insufficient. If it is, your right of action is on the contractor's performance bond (§§ 573.25, 573.19, 573.23).
• On public works, the contractor can serve you with a written demand to commence action. Thirty days later, if you have not sued, the retained and unpaid funds are released to the contractor (§ 573.16(2)).