A general contractor finishes a $40,000 change order in March. The property owner signs off on the extra work, agrees the price is fair, then simply... doesn't pay. Not disputes it — just sits on it. Six months and several unreturned calls later, the contractor is still owed the money, still hasn't been able to build a paper trail strong enough to force payment, and has eaten the labor and material costs out of pocket the whole time.
That scenario used to be a routine cost of doing business in California construction. As of January 1, 2026, it's also a violation of state law — one that now comes with a 24%-a-year penalty attached.
What Changed: The Private Works Change Order Fair Payment Act
Senate Bill 440, known as the Private Works Change Order Fair Payment Act, took effect this year and rewrote how disputes over change orders get resolved on private construction projects in California. It's codified at California Civil Code sections 8850 through 8859, and unlike a lot of construction legislation, it isn't buried in procedural language that only a litigator would love. It sets hard deadlines, in days, that owners and contractors can actually calendar.
Here's the mechanism:
- 30 days — once a contractor submits a change order claim, the owner has 30 days to respond and specify which portions of the claim are disputed and which are undisputed.
- 60 days — the owner must pay the undisputed portion within 60 days of the original claim, regardless of how the disputed portion shakes out.
- 2% per month — any undisputed amount that isn't paid on time starts accruing interest at 2% monthly, which compounds out to 24% annually. That rate also applies retroactively to disputed amounts that are later confirmed owed through mediation, arbitration, or a court judgment.
- Stop-work rights — if an owner blows through the payment deadline on an undisputed amount, the contractor can suspend work with 10 days' written notice, without it counting as a breach of contract on their end.
The law covers most private works of improvement in California. It carves out an exception for smaller residential buildings — specifically non-mixed-use structures of four stories or fewer built with Type V (wood-frame) construction — on the theory that homeowners shouldn't be subject to the same claims machinery as commercial developers. Subcontractors who aren't in a direct contract with the owner aren't left out either: they can route their change order claims through the general contractor and still get the benefit of the deadlines and interest penalty.
SB 440 arrived alongside a companion bill, SB 61, which caps retention withholding on private projects at 5% of the contract value — a limit that previously applied mainly to public works. Together, the two laws mark a real shift in leverage: money that used to sit in an owner's account earning nothing for the contractor now has a statutory cost attached to holding onto it.
It's Not Just California
SB 440 is the most detailed 2026 update, but it's part of a broader pattern. Prompt payment statutes exist in some form in every state, and lawmakers have spent the past several years replacing vague "reasonable time" language with bright-line day counts and fixed interest rates — because vague language is exactly what let slow-paying owners run out the clock in the first place.
A few reference points if you work across state lines:
- California's base Prompt Payment Act (separate from SB 440) already required private owners to pay contractors within 30 days of an undisputed invoice, and required general contractors to pay or formally dispute a subcontractor's invoice within 7 days of receiving it. Public agencies get somewhat longer windows depending on the entity.
- Texas sets its prompt payment interest rate at 1.5% per month (18% annually), running from the missed due date until the payment is made or a court enters judgment.
- Design professionals — architects, engineers, surveyors — are generally carved out of these statutes and governed by separate rules, so don't assume the same clock applies to a design contract.
If you do business in more than one state, the practical takeaway is the same everywhere: know your state's specific deadline and interest rate before you're the one waiting on a check, and check it again before you sign a contract that tries to override it — some of these protections can be waived by agreement, and the fine print is where that usually happens.
What This Means If You're the One Owed Money
The law only helps you if you can prove what happened, and that's where a lot of legitimate claims fall apart. A verbal change order that the client "totally agreed to" is worth very little if it's your word against theirs in a dispute. Practical steps that actually hold up:
- Put every change order in writing, even a one-line email confirming scope and price, before you do the work. If the client won't confirm in writing, that's information too.
- Send claims and demand letters by a method that creates a delivery record — certified mail with return receipt, or a platform that logs timestamps — so the 30-day and 60-day clocks are provable, not just asserted.
- Track the calendar deadlines like you'd track a filing deadline, because that's effectively what they are. Note the date a claim was submitted, the date the owner's response was due, and the date interest starts accruing if payment doesn't show up.
- Separate disputed and undisputed amounts in your own records the moment an owner does, so you can show exactly what should have been paid on day 60 even if a smaller line item is still being negotiated.
Where This Connects to Your Books
Interest penalties, retention caps, and payment deadlines aren't just legal concepts — they're line items. An unpaid change order that's accruing 2% monthly interest is a receivable that's actively growing in value, and if your books don't reflect that, you're understating what the business is actually owed. Retention held under the new 5% cap needs its own account so it doesn't get lost inside a lump "accounts receivable" balance and forgotten about for a year.
This is one of the places where plain-text, version-controlled bookkeeping earns its keep: every invoice, change order, and accrued-interest entry is a dated, auditable line you can point to if a payment dispute ever ends up in front of a mediator. A spreadsheet that gets overwritten every month doesn't give you that. A ledger with full history does.
Simplify Your Financial Management
Tracking change orders, retention, and interest accrual by hand is exactly the kind of bookkeeping that gets messy under deadline pressure — right when you need it to be airtight. Beancount.io offers plain-text accounting that's transparent, version-controlled, and easy to audit, so every claim, payment, and penalty has a paper trail you can actually stand behind. Get started for free and keep your project finances as organized as the law now expects your clients' payments to be.