New York mechanic's liens

Who and what this applies to

Private real-property improvement liens and public-improvement fund liens under Lien Law Article 2.

Thresholds and scope

Filing, service and continuation rules differ between private and public improvements.

The rules

• Private qualifying labor/materials furnished with owner consent/request or through the authorized contracting chain can support a real-property lien upon filing. Source
• Private notices are generally filed within eight months of last work/materials; qualifying single-family dwellings use four months. The statutory developer-owned subdivision exception applies. Retention claims may be filed within 90 days after retention became due. Source
• Serve the owner between five days before and 30 days after filing by statutory methods; file service proof within 35 days after filing or the lien terminates. Source
• Also serve the contracting party by certified mail within the same five-before/30-after window, and the contractor where the lienor lacks a direct contractor contract; service proof is due within 35 days. Source
• Private liens normally last one year after filing unless timely foreclosure and lis pendens, or a valid extension. Single-family extensions require a court order; section 17 has separate rules for liens discharged by security. Source
• Public-improvement liens attach to applicable contract funds due/to become due, not public real estate. Source
• File a public notice with the responsible department head and designated financial officer before, or within 30 days after, completion and acceptance. Source
• For public notices, serve contracting/upstream parties by certified mail within five days before or simultaneously with filing, and file proof with the notice; missing proof makes it a nullity. Source
• Public liens generally last one year; preserve them through timely foreclosure plus notice of pendency filed with the designated financial officer, or a statutory extension. Source

Primary sources

• N.Y. Lien Law §3
• N.Y. Lien Law §10
• N.Y. Lien Law §11
• N.Y. Lien Law §11-b
• N.Y. Lien Law §17
• N.Y. Lien Law §5
• N.Y. Lien Law §12
• N.Y. Lien Law §11-c
• N.Y. Lien Law §18

Sources reviewed 2026-09-30. This guide covers the projects and rules stated above.

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