Why Prop 37 Fits SB 684, SB 1123 and AB 1751: State Down Payment Help for New Homes

General information only. This article is educational and is not legal, tax, financial, lending or investment advice. Do your own due diligence and confirm everything with your own qualified professionals before relying on it. Read the full disclaimer.

For three years, California housing law has mostly worked on the supply side. SB 684 and SB 1123 let a qualifying lot become as many as ten fee-simple homes without a public hearing. AB 1751 extends that approach to townhome projects of up to 150 homes from January 1, 2027.

On November 3, 2026, voters added the demand side. Proposition 37 lets the state lend buyers up to 17 percent of the purchase price, but only for a newly built home. This article explains why that restriction lines up so closely with the homes these laws produce, and what it does and doesn’t change for new-construction housing in Los Angeles.

Prop 37 in One Paragraph

CalHFA may issue up to $25 billion in revenue bonds and lend eligible buyers up to 17 percent of the price as a fixed-rate second mortgage. The buyer adds at least 3 percent of their own money, which makes a 20 percent down payment. Buyers must have lived in California for a year, earn no more than 200 percent of area median income, and move in within 60 days. The home must be new, the buyer must be its first purchaser, and the price must be under 125 percent of the county’s conforming loan limit, about $1.56 million in Los Angeles County based on the 2026 limit. The measure is aimed at first-time buyers and renters, though it does not require borrowers to be first-time buyers.

Why a New-Construction-Only Program Matters

Most down payment programs, including CalHFA’s existing ones, can be used on any home. Prop 37 can’t. Every dollar it lends goes to the first sale of a home that did not exist before.

That ties the state’s largest down payment program directly to new supply. A buyer who wants Prop 37 help has to buy a new home, and the laws that make new for-sale homes possible on infill land are SB 684, SB 1123 and AB 1751.

How Each Law Lines Up

Every home is new, so every first buyer meets Prop 37’s first-purchaser rule. The open question for any given home is the price.

Four Reasons the Fit Is Close

1. The size limit works in the buyer’s favor

All three laws cap the average home at 1,750 net habitable square feet. Smaller homes on smaller lots tend to cost less than the larger detached houses around them, which makes it more likely they fall under the Prop 37 price cap. On the most expensive Westside streets some new homes will still land above it.

2. Fee-simple homes finance like houses

Each home sits on its own lot with its own parcel number, so a lender can underwrite it as a single-family home. That keeps the structure simple: a conventional first mortgage at 80 percent, with the Prop 37 loan behind it. See how SB 684 homes are financed.

3. The buyer is the same person

Prop 37 is written for middle-income households who can carry a mortgage but haven’t saved a full down payment. That is the buyer a modestly sized fee-simple home on an infill lot is designed for.

4. Home-by-home sales meet a home-by-home loan

SB 684 and AB 1751 homes sell individually to owner-occupants, one closing at a time. Prop 37 is a loan to one owner-occupant on one home. Nothing about the structure has to change for the two to work together.

How the Timelines Line Up

On recent Westside SB 684 projects, entitlement and construction each take about a year. That puts many of them on the market around the time Prop 37 loans should become available.

The Builder Side: The Qualified Builder Option

Any builder’s homes can be sold to Prop 37 buyers. The measure also offers an optional “qualified builder option”: builders who opt in accept higher labor standards and, in return, their Prop 37 homes follow a modified construction-defect process. Builders who sell a home more than 25 percent above the price cap lose those modified rules for that home. Whether opting in makes sense will depend on the project and its labor costs, and it is a decision we expect to make project by project.

What Prop 37 Doesn’t Change

• It isn’t running yet. CalHFA still has to set the interest rate, terms, underwriting rules and approved lenders.
• The money is finite. $25 billion covers a limited number of loans, and it depends on investors buying the bonds.
• Payments still have to work. A down payment loan doesn’t lower the monthly cost. Buyers must qualify for two loans at current interest rates.
• The price cap moves. It resets each year with the FHFA’s conforming loan limits.
• It doesn’t change the approval rules. SB 684, SB 1123 and AB 1751 sites still have to qualify on their own terms.

How It Fits Our Strategies

Assemble Capital builds new fee-simple homes on Los Angeles infill land and sells them individually to owner-occupants. SB 684 and SB 1123 are our core small-lot strategy, and as AB 1751 takes effect, part of our syndication model will be facilitating AB 1751 townhome projects where a site qualifies.

Prop 37 is aimed at the buyers those homes are built for. Until CalHFA launches the program, we treat it as a possible help to buyers, not something a project depends on. As the rules are published, we will track the price cap and income limits in the counties where we build, review the qualified builder option for each project, and make sure buyers and their agents know which of our homes are eligible.

For a buyer’s view of the same question, see how Prop 37 helps first-time buyers purchase SB 684 and AB 1751 homes.

Frequently Asked Questions

How does Prop 37 relate to SB 684 and AB 1751?
Prop 37 lends buyers up to 17% of the price of a newly built home. SB 684, SB 1123 and AB 1751 make new fee-simple, for-sale homes easier to approve and build. One law adds supply, and the other helps buyers afford the down payment on that supply.

Do SB 684, SB 1123 and AB 1751 homes qualify for Prop 37?
The home types do. Prop 37 covers newly built stand-alone homes, townhomes, row houses and condominiums sold to their first purchaser. Each home must also be priced under the county cap, and each buyer must meet the income, residency and occupancy rules.

Why does the 1,750 square foot limit matter for Prop 37?
All three laws cap the average home at 1,750 net habitable square feet. Smaller homes tend to cost less than larger detached houses nearby, which makes it more likely they fall under Prop 37’s price cap, about $1.56 million in Los Angeles County based on the 2026 limit.

Is Prop 37 available yet?
No. CalHFA has up to one year after the measure takes effect to launch the program, and it still has to set rates, terms and underwriting rules.

What is the Prop 37 qualified builder option?
An optional track for builders. Builders who opt in accept higher labor standards and, in return, follow a modified construction-defect process on their Prop 37 homes. Builders who do not opt in can still sell eligible homes to Prop 37 buyers.

Sources and Review

Prop 37 provisions summarized from the official voter guide and the measure text filed with the Attorney General; AB 1751 from the chaptered bill text; SB 684, SB 1123 and SB 1116 from our SB 684 guide and SB 1116 article. The Los Angeles County price cap is based on the FHFA’s 2026 conforming loan limit. General information, not lending, legal or investment advice.

Related Reading

Keep Going.

Or see how this plays out in practice: SB 684/1123 Fee Simple Subdivisions.