Prompt payment statutes set the maximum number of days an owner, GC, or public agency can hold a proper payment application before it becomes overdue, and they specify the interest penalty for non-compliance. Nearly every state has some form of prompt pay law, but the details — deadlines, triggers, interest rates, dispute procedures, and penalties — vary dramatically from state to state and between public and private projects.

On federal projects, the federal Prompt Payment Act requires payment to the prime contractor within 14 days of a proper invoice from the owner, and payment to subcontractors within 7 days of the prime receiving funds. Many states model their laws similarly but with different day counts. State public project prompt pay laws typically specify that the public entity must pay within 30–45 days of a proper invoice. Private project laws are more variable — some states have robust private-sector prompt pay protections; others have minimal or no private-sector coverage.

The trend is tightening. States are increasingly moving toward "bright-line" prompt pay rules — fixed, objective deadlines rather than vague "reasonable time" standards that are difficult to enforce. New York, California, and Texas have all strengthened prompt pay provisions in recent years. Contractors operating across multiple states need state-specific knowledge, not a single assumed timeline, because a 30-day assumption in a state that actually requires 14-day payment leaves real money on the table in interest recovery.

Retainage rules vary significantly between states, project types (public vs. private), and phases of work. At the extremes: New Mexico prohibits retainage on most publicly and privately funded projects. At the other end, states with no retainage cap on private projects allow contractual retainage at whatever rate the parties agree — sometimes 10% throughout the entire project. States are roughly divided between those capping retainage at 5% and those capping it at 10%, with 5% becoming the more common standard for public work.

On federal construction, the standard retainage rate is 10%, but contracting officers are expressly authorized to reduce or eliminate retainage after 50% completion for contractors demonstrating satisfactory performance. This authority is underused — prime contractors should proactively request retainage reduction at the 50% milestone rather than assuming it will happen automatically. Similarly, many state public contracts allow retainage reduction for satisfactory performance milestones; subcontractors should confirm whether GC subcontracts pass through this right.

Several states have enacted retainage reduction provisions that are triggered automatically at a specified percentage of completion — commonly 50%. California, Florida, and Washington are among states with these automatic reduction provisions on public projects. Know whether your state's statute requires the reduction or merely permits it, and whether the GC subcontract preserves or waives your right to reduced retainage on public work.

Notice requirements are the procedural layer beneath payment rights. They come in multiple forms: preliminary notices to establish lien rights; notice of delay or claim to preserve contract rights for additional compensation; notice of nonpayment to trigger GC payment obligations on public work; and notice of intent to lien as a pre-lien demand step required in some states before filing a mechanics lien. Missing any of these notice deadlines can permanently waive the rights the notice was designed to protect.

Public construction notice requirements are particularly strict and often different from private project requirements. Many states require a sub on a public project to notify the prime contractor of nonpayment within a specific window — often 30–90 days of the overdue amount arising — before they can claim against the payment bond. Unlike private projects where lien rights attach to the property, public project remedies typically run through the payment bond, and the procedural requirements for bond claims are set by statute and are not forgiving of late notice.

A practical notice management system for multi-state contractors: maintain a project-specific notice calendar at project start, populated with every deadline for every required notice type for that state and project type. Don't manage this in someone's head or a general project calendar — use a dedicated legal deadline tracker. The consequences of a missed preliminary notice (lost lien rights) or missed bond claim notice (lost bond claim) are financially severe and not recoverable through any other remedy.

The distinction between public and private construction fundamentally changes the payment rules in four ways. First, public projects have no lien rights — you cannot lien public property. Instead, subcontractors and suppliers are protected by statutory payment bonds (required by the Miller Act federally and state equivalents locally). Second, public project payment timelines are set by statute and are not fully contractually modifiable — a public agency cannot contract away the requirement to pay within the statutory window. Third, prompt pay interest rates are often set by statute on public projects. Fourth, the notice requirements and deadlines for bond claims differ from mechanics lien procedures.

On private projects, the rules are more contract-driven — the owner and prime can structure payment terms, retainage, and dispute procedures within the limits of state statutes. Pay-when-paid and pay-if-paid clauses are particularly impactful on private work: pay-when-paid clauses (payment to sub is due within a reasonable time after GC receives payment) are enforceable in most states; pay-if-paid clauses (sub is only paid if GC gets paid) are enforceable in some states and void against public policy in others. Know your state's position on both clause types before signing a subcontract with one.

Interest on late payment is where many contractors leave money. Most state prompt pay statutes specify a default interest rate on overdue payments — commonly 1–1.5% per month (12–18% annualized) — that accrues automatically without requiring the payee to demand it. On a $200,000 overdue invoice at 1% per month, two months of delay generates $4,000 in recoverable interest. Tracking overdue amounts and applying prompt pay interest claims on collection is a legitimate and underutilized revenue recovery tool.

Understanding your state's payment laws before signing a subcontract converts abstract legal knowledge into negotiating leverage. If your state caps retainage at 5%, a subcontract demanding 10% contains an unenforceable provision — and you can negotiate it out by citing the statute rather than asking for a favor. If your state requires interest on overdue payment at 1.5% per month, your collection demand letters should include calculated interest — it transforms an informal request into an enforceable demand backed by law.

A few states have enacted "pay-when-paid" flow-down limits that cap how far up the contract chain a payment delay can be imposed. Texas, for example, has both a strong prompt payment statute and specific provisions on the enforceability of pay-when-paid clauses at different tiers. Florida amended its construction contract statute to tighten prompt pay requirements, adding penalties for unsubstantiated withholding. Knowing these protections lets you call out contractual provisions that conflict with the statute rather than discovering the conflict only when payment is withheld.

The most effective use of state payment law knowledge is proactive: building your notice calendar, drafting your scope of work to make "completion" objectively measurable (which determines when prompt pay clocks start), and negotiating retainage release milestones into the subcontract at award rather than fighting for them at closeout. Laws that protect contractors on paper only protect them in practice when contractors know the law and use it as a planning tool — not just a dispute remedy.