Chico ADU Laws 2026: Build Two Backyard Units? (Guide)

May 8
4 min read

Quick Summary: Can You Build Two Units in Your Backyard?

Yes, but the strategy matters. Under 2026 California laws (including SB 9 and updated ADU statutes), homeowners in Chico's single-family zones (RS and R1) can typically achieve multiple units in one of two ways:

The ADU Path: One full Accessory Dwelling Unit (up to 1,200 sq. ft.) plus one Junior ADU (up to 500 sq. ft.).
The SB 9 Path: Building two "primary" units (a duplex) or splitting your lot to build up to four units total.
The 2026 Update: New "shot-clock" rules mean the City of Chico must now review your application for completeness within 15 business days.

Chico ADU Laws 2026: Can You Really Build Two Units in Your Backyard?

You’ve seen them popping up all over the Barber Neighborhood and near Bidwell Park—sleek, modern cottages tucked neatly behind classic Chico homes. With housing demand at an all-time high in Northern California, the question we get most at PMS Remodeling is no longer "Can I build an ADU?" but "Can I build two?"

The short answer is: Yes. But 2026 has brought some specific legal "fine print" that determines whether those units are considered ADUs, a duplex, or an SB 9 lot split.

Having navigated the Butte County building department for over 12 years, our team is here to break down exactly what you can build on your property this year.

1. The "Three-Unit" Reality for Single-Family Lots

For most homeowners in Chico, the most straightforward path is the 1+1 Rule. Under current state law, if you own a single-family home, you are legally entitled to:

One Detached ADU: Up to 1,200 square feet.
One Junior ADU (JADU): Up to 500 square feet, typically converted from existing space like a garage or a spare bedroom.

2026 Pro-Tip: A major change this year (via AB 1154) has officially removed the owner-occupancy requirement for many JADUs. This means you can now rent out the main house, the ADU, and the JADU simultaneously, turning your backyard into a triple-stream income property.

2. Doubling Down: Using SB 9 for Two Primary Units

If you want two full-sized homes in your backyard rather than one small ADU, we look toward Senate Bill 9 (SB 9).

In Chico’s R1 and RS zones, SB 9 allows you to build a second primary unit. Unlike an ADU, these units can sometimes be sold separately if you perform an "Urban Lot Split."

What you need to know for 2026:

Parking: While ADUs often don't require parking if they're near a B-Line bus stop, SB 9 units usually require one off-street parking space per unit.
Impact Fees: ADUs under 750 sq. ft. are exempt from many city impact fees. SB 9 units, however, are treated as primary dwellings and will likely incur full development fees.

3. Navigating Chico’s 2026 Building Codes

The City of Chico has streamlined the process, but they are strict about local aesthetics and safety. Our team at PMS Remodeling works closely with the Planning Division to ensure every project hits these marks:

Setbacks: You generally only need 4-foot side and rear setbacks for new ADUs. This is a huge win for narrow lots in the Avenues.
Height Limits: Detached ADUs can now reach up to 16–25 feet depending on your proximity to transit and your main home’s height.
Climate Considerations: We focus on "Chico-proof" builds. This means high-efficiency HVAC systems to handle our 100°F+ summers and fire-resistant siding—a must for Butte County residents.

4. Why 2026 is the Year to Build

The "red tape" is finally thinning. As of January 1, 2026, California has implemented a private plan-check option. If the local building department is backed up and can’t review your plans within 30 days, you now have the right to hire a certified private professional to speed up the process.

At PMS Remodeling, we’ve spent years refining our workflow so your project doesn't sit on a desk at City Hall. We handle the permits, the design, and the heavy lifting.

FAQ: People Also Ask About Chico ADUs

Q: How much does a permit cost for an ADU in Chico? A: For a standard 800 sq. ft. unit, expect permit and plan-check fees to range between $5,000 and $12,000. However, if your unit is under 750 sq. ft., you can save thousands because the city cannot charge "Impact Fees."

Q: Can I build a two-story ADU? A: Yes! Under the 2026 standards, if you are within a half-mile of a major transit stop (like those near CSU Chico), you can often build up to 25 feet high. This is perfect for putting a rental unit over a new garage.

Q: Does an ADU increase my property taxes? A: Your primary home will not be reassessed. Only the new construction (the ADU) will be added to your property's value, which typically results in a very modest increase compared to the rental income the unit generates.

Ready to Maximize Your Backyard?

Whether you're looking to house a family member or build a high-end rental, PMS Remodeling has the local expertise to get it done right. We live and work in Chico, and we treat every project like it's in our own neighborhood.

Free Consultation: Ready to see if your lot qualifies for two units? Contact us today for a site evaluation!