California gives subcontractors real payment security — mechanics liens on private work, stop payment notices and payment bonds on public work. But nearly all of it hangs on one routine piece of paper sent at the start of the job: the preliminary notice. Skip it, and the strongest collection tools in the state mostly evaporate, no matter how good your work was.

The short version

  • Subcontractors and suppliers must serve a California preliminary notice within 20 days of first furnishing labor or materials — on essentially every job, private or public.
  • It’s an informational notice, not a lien or a claim — professional shops send one on every job, day one.
  • A late notice still works, partially: it protects work furnished from 20 days before service onward. If you missed it, send it today.
  • Serve the owner, direct contractor, and construction lender by certified or registered mail, and keep proof of service in the job file.
  • The deadlines that follow are short: lien recording windows of 30–90 days around completion, and a foreclosure suit within 90 days of recording — use-it-or-lose-it, all the way down.

What it is — and what it isn’t

The preliminary notice (the “20-day notice”) is an informational notice telling the owner, the direct contractor, and the construction lender that you’re furnishing labor or materials to the project. It is not a lien, not a claim, and not an accusation that anyone owes you money. It’s a prerequisite: California requires it so that owners and lenders know who’s on the job and could later claim against the property or the funds.

Some subs hesitate to send it, worried the GC will read it as hostile. Don’t. Sophisticated GCs and owners expect preliminary notices from every sub and supplier on day one — a shop that sends them on every job reads as professional, not adversarial.

Who has to send one

  • Subcontractors and material suppliers — yes, on essentially every job, private or public. If you don’t have a direct contract with the owner, the preliminary notice is what preserves your rights.
  • Direct contractors — on private jobs, only to the construction lender, if there is one.
  • Wage laborers — exempt.

On private work it protects mechanics lien and stop payment notice rights; on public work (where there’s no lien on government property) it protects your stop payment notice and payment bond claims — the notice goes to the public entity and the direct contractor.

The 20-day window — and what “late” actually costs

Serve the notice within 20 days of first furnishing labor or materials to the project. That’s calendar days, and the clock starts at first furnishing — not at contract signing, and not at first invoice.

Miss the window and the notice isn’t void — it’s trimmed. A late preliminary notice protects only the work you furnish from 20 days before service onward. Everything earlier is unprotected. So the practical rule: if you discover mid-job that no notice went out, send it that day. You lose the early work; you save the rest of the contract.

How to serve it

Send it to the owner (or reputed owner), the direct contractor, and the construction lender if there is one — by registered or certified mail, express mail, or overnight courier. Keep the proof of service and the tracking record with the job file; an unprovable notice is barely better than no notice. The names and addresses should come from the contract documents — and if the GC’s paperwork doesn’t identify the owner and lender, ask in writing.

The deadlines that follow

The preliminary notice opens the door; the deadlines that follow are what you walk through, and they’re short:

  • Recording a mechanics lien (private work): if a notice of completion or cessation is recorded, subcontractors generally have 30 days from that recording (direct contractors get 60). If none is recorded, the deadline is generally 90 days after completion of the whole work of improvement.
  • Enforcing the lien: you must file a foreclosure lawsuit within 90 days of recording the lien, or it expires. A recorded-and-expired lien is worse than none — you may have to remove it.
  • Public work: stop payment notices and payment bond claims carry their own short post-completion windows — same discipline applies.

The pattern to internalize: every right in this chain is use-it-or-lose-it, on a clock measured in weeks. The shops that collect aren’t the litigious ones — they’re the ones whose paperwork was already perfect when the payment problem started.

Make it a system, not a decision

The failure mode isn’t ignorance — it’s treating the notice as a judgment call per job (“the GC’s good for it”). By the time you know a job is a payment problem, the 20-day window is long gone. Send a preliminary notice on every job, first week, no exceptions, and track first-furnishing dates, service dates, and proof of service in one place. It’s ten minutes of admin that keeps your leverage alive for the entire project.