California Civil Code 8850 & 8811 – what contractors need to know in 2026

California has introduced significant reforms to private construction contracting through Civil Code § 8850 and § 8811, taking effect from January 2026. The changes centre on two key measures: a mandatory, non‑waivable claims and mediation process that requires owners to engage with and pay claims within fixed timelines, and a strict 5% cap on retention across the supply chain. Together, these reforms aim to improve contractor cash flow, accelerate the resolution of change‑order disputes and reduce project delays. For international contractors active in US infrastructure and energy, they reflect a broader global shift towards greater payment discipline and early dispute‑resolution frameworks.

The current landscape – why reform was needed

Private works in California have long lacked the structured claims‑handling regime that governs public sector projects. Delayed change orders, slow or incomplete owner responses, and withheld payments have routinely created significant working‑capital pressure for contractors. At the same time, retention on private projects often exceeded 5-10%, further tightening liquidity across the supply chain. These persistent issues shaped the Legislature’s policy priorities, which now emphasise prompt payment, early dispute resolution, and more efficient project delivery.

The new structured claims process – Civil Code § 8850

Civil Code § 8850 introduces a clear definition of a “claim,” covering time‑extension requests, extra or changed work, and owner‑disputed sums. Claims must be submitted with supporting documentation and served by registered or certified mail. Once received, the owner has 30 days to respond and identify the disputed and undisputed elements. Section 8850 operates alongside, rather than replacing, California’s existing prompt‑payment laws. Under the new regime, undisputed sums must be paid within 60 days, and a failure to respond results in the claim being automatically deemed denied – significantly accelerating the claims cycle.

Where issues remain unresolved, parties must meet and confer within 30 days, after which the owner must issue an updated statement within 10 business days. Any remaining disputes move to non‑binding mediation, with the contractor entitled to select the mediator if the parties cannot agree. The process applies throughout the supply chain, including between contractors and subcontractors, ensuring full pass‑through of rights and obligations. Projects are generally exempt only where they are non‑mixed‑use residential and do not exceed four storeys.

The reforms are reinforced by a set of powerful enforcement tools. Most notably, unpaid undisputed amounts accrue interest at a rate of 2% per month, and this rate can also apply retroactively to disputed sums that are later upheld, potentially creating significant financial exposure for owners who delay. In parallel, contractors and subcontractors now benefit from statutory stop‑work rights, enabling them to suspend performance (subject to notice requirements) if an owner fails to respond, pay, or participate in the process. This includes a 30‑day payment‑due notice followed by a further 10‑day notice before suspension occurs. Importantly, all of these provisions are non‑waivable, meaning contractual terms cannot dilute or override the statutory regime.

Retention reform – Civil Code § 8811

Civil Code § 8811 introduces a strict 5% cap on retention at every tier of the project, whether withheld by owners, contractors or subcontractors, for both progress payments and the overall contract value. There are only limited exceptions, notably for certain low‑rise residential projects and subcontractors who fail to provide required performance and payment bonds. The statute also provides for mandatory attorney’s fees in enforcement actions. The reform is designed to ease liquidity pressures, particularly for smaller contractors, and to bring private‑sector retention practices closer to the long‑standing limits already applied on California public works. It also prevents front‑loading of retention, supporting steadier cash flow throughout project delivery.

International perspective and success

Many jurisdictions – including the UK (HGCRA 1996), Australia (e.g. NSW 1999 Act), and Singapore (Building and Construction Industry Security of Payment Act 2004) – already operate prompt‑payment or early‑resolution regimes. California’s reforms now place it firmly within that global trend.

International contractors working across the US will increasingly need to navigate state‑specific statutory processes, integrating them into their commercial, claims and project‑controls systems. The new 5% retention cap mirrors reforms seen overseas and signals a growing consensus that protecting contractor cash flow is essential to delivering major projects efficiently.

Taken together, the reforms should enhance cash flow across the supply chain and reduce disputes driven by owner inaction or delayed payment decisions. The structured escalation route which culminates in mandatory mediation, has the potential to resolve issues earlier and prevent unnecessary progression into litigation or arbitration. That said, the new framework is not without challenges. The statutory timelines and documentation requirements are likely to increase the administrative burden, particularly for owners and project managers, and it remains to be seen whether the intended efficiencies will outweigh the added compliance obligations.

Key takeaways

• California’s Civil Code reforms seek to accelerate dispute resolution, strengthen liquidity and rebalance risk across the private construction sector.
• Whether they ultimately reduce disputes or simply introduce new layers of compliance will depend on how effectively parties adapt to the new framework.
• Private works in California will now operate within a statutory regime every bit as structured as the public sector.
• For international contractors, staying ahead of jurisdiction‑specific regulatory change is essential as global project delivery becomes increasingly complex and closely governed.
• Mandatory escalation to mediation under § 8850 will likely increase mediation volumes, heightening demand for experienced construction mediators.

If you have any questions in respect of the above, then please contact the authors.