Carmichael ADU Regulations: A Comprehensive Guide 2026

Carmichael is a mature, leafy suburb in unincorporated Sacramento County with around 82,000 residents in 2026 and about 17 square miles of mostly built-out neighborhoods.

Because it’s not a city (it’s an unincorporated census-designated place), all zoning and permitting — including Accessory Dwelling Units (ADUs) — are governed by Sacramento County, not a local city council.

What Is an ADU (and a JADU) in Carmichael?

Sacramento County defines:

• Accessory Dwelling Unit (ADU) – A self-contained residential unit on the same lot as a primary home, with:
  • Its own kitchen (full kitchen, not just a wet bar)
  • Bathroom
  • Sleeping / living area
  • Separate exterior entrance
  • Built on a permanent foundation and meeting residential building standards.
• Junior ADU (JADU) – A smaller unit that is:
  • No more than 500 sq. ft.
  • Located entirely within the permitted area of the primary dwelling (including attached garage or storage)
  • Includes at least an efficiency kitchen
  • May share a bathroom with the main house.

Tiny homes on wheels and RVs do not count as ADUs in Sacramento County; they’re not allowed as permanent dwellings on standard residential lots.

Why ADUs Make Sense in Carmichael

Carmichael is known for older single-family neighborhoods, large trees, good schools, and strong park and nature access (Effie Yeaw Nature Center, Ancil Hoffman Golf Course, etc.).

ADUs are especially attractive here because:

• Steady population and rent growth: Carmichael’s population has climbed to over 82k with roughly 1.7% annual growth since 2020; rental demand stays solid in this inner-ring suburb.
• Lots that can fit a cottage: Many Carmichael parcels have deep backyards or side yards, making detached ADUs easier to site. Local builders market ADU models from ~300–1,200 sq. ft. specifically for Carmichael lots.
• Income & retirement strategy: Carmichael-focused ADU builders highlight potential rents up to roughly $2,500/month for well-located units, along with use as retirement housing instead of costly assisted living.
• County & state support: Sacramento County’s 2026 ADU standards and its “Shelf Ready ADU” plan program significantly simplify design and permitting for unincorporated areas like Carmichael.

Can I Build an ADU in Carmichael?

Short version: If your Carmichael property has (or will have) a primary dwelling, you can almost certainly build an ADU.

Sacramento County’s ADU handout says:

• Any property developed with a primary residential use may have ADUs and JADUs, as laid out in Table 1 of the zoning standards.

For single-family or half-plex lots you can have up to three units total in various combinations:

• 1 new detached ADU, plus
• 1 JADU, plus
• 1 other ADU that’s either:
  • a new attached ADU, or
  • an attached conversion (within the house), or
  • a detached conversion (e.g., a garage conversion).

For multifamily properties (duplexes, apartments), the County allows:

• Up to two new detached ADUs, and
• Conversion ADUs equal to up to 25% of the existing unit count from non-living space (at least 1), with a special 2026 allowance for up to 8 new detached ADUs for existing multifamily sites.

Carmichael ADU Laws & Regulations (2026)

All of the rules below come from Sacramento County’s 2026 ADU/JADU standards, which apply directly in Carmichael.

Unit Types Allowed

In Carmichael (unincorporated Sacramento County), you can generally build:

• Detached ADU – freestanding backyard cottage
• Attached ADU – addition connected to the main house
• Detached conversion ADU – converting an existing permitted garage or accessory structure
• Attached conversion ADU – converting part of the home’s interior
• Junior ADU (JADU) – ≤500 sq. ft. unit within the primary dwelling or attached garage

Manufactured homes on a permanent foundation can be used as ADUs; RVs/tiny homes on wheels cannot.

Maximum Unit Size

Sacramento County’s 2026 table sets these caps:

• Detached ADU (new construction)
  • Max 1,200 sq. ft. (no further increases allowed).
• Attached ADU (new construction) – maximum is the greater of:

1. 50% of the habitable floor area of the primary dwelling, or
2. 850 sq. ft. (studio/1-bed), or
3. 1,000 sq. ft. (2+ bedrooms).

• JADU
  • 500 sq. ft. inside the proposed primary dwelling (including attached garage/storage), plus 150 sq. ft. for ingress/egress additions.
• Conversions of existing space
  • ADU: size equals the existing permitted structure plus up to 150 sq. ft. for ingress/egress.
  • JADU: up to 500 sq. ft. of existing interior space plus 150 sq. ft. for ingress/egress.

State law also guarantees you can build at least an 800-sq-ft ADU (with 4-ft side/rear setbacks and up to 16 ft tall) even if lot-coverage rules would normally block it.

ADU Height Limits

Default maximum building heights in Sacramento County (to the peak) are:

• Detached ADU (single-family) – 16 ft
• Attached ADU – 25 ft or the primary dwelling’s height limit, whichever is less
• Detached ADU in a multifamily project – 18 ft

Height increases for detached ADUs are allowed:

• Up to 20 ft total if you provide at least 10 ft rear and 5 ft side setbacks.
• Up to 18 ft (plus extra height for matching roof pitch) if within ½ mile of a major transit stop or needed to align with the primary home’s roof.

Detached ADUs are limited to one story by default; attached ADUs can be two stories.

Setback Requirements

“Default” ADU setbacks for Carmichael (Sacramento County) are:

• Front yard: 20 ft
• Side-street yard (corner lot): 12.5 ft
• Side and rear yards: 4 ft (for both attached and detached ADUs)

Important nuances:

• Existing permitted structures converted to ADUs may keep their original setbacks, even if closer than 4 ft.
• In some special zoning overlays (SPAs, Neighborhood Preservation Areas, Planned Developments), the front and side-street setbacks from that overlay apply instead.
• If enforcing a standard would physically prevent an 800-sq-ft ADU, the Planning Director can approve minor deviations to front/side-street setbacks, lot coverage, or open space.

Parking Requirements

Sacramento County sets one off-street parking space per ADU, unless a waiver applies.

You do not need to provide parking for the ADU if:

1. The ADU is within ½ mile walking distance of public transit.
2. It’s in a historic district (architecturally/historically significant).
3. The ADU is part of the existing primary dwelling or accessory structure (i.e., a conversion).
4. On-street parking permits are required, but not offered to the ADU occupant.
5. There is a car-share vehicle within one block.
6. The ADU is a new detached unit 800 sq. ft. or smaller.
7. The ADU is accessory to a multifamily dwelling.

And when you convert or demolish a garage, carport, or parking space for an ADU, you do not have to replace that parking.

Local ADU builders summarise this for Carmichael as: min. one space unless you qualify for the common exemptions, which many projects do (especially conversions and smaller units).

Building Permits and Fees

Because Carmichael is unincorporated, you’ll work directly with Sacramento County:

• Planning & Environmental Review – zoning, setbacks, height, number of units.
• Building Permits & Inspection – structural, fire/life safety, electrical, plumbing, mechanical, energy code.

Key points from the County’s 2026 ADU handout:

• All ADUs (new or conversions) require a building permit.
• Converting a garage or accessory structure is a change of use, so the building must be upgraded to current residential standards.
• The County has “Shelf Ready ADU” plans — 460, 870, 1,000, and 1,184 sq. ft. detached units — that Carmichael homeowners can use to speed up design and plan review.

Impact fees & costs

• Sacramento County notes that ADUs under 750 sq. ft. are exempt from development impact fees; ADUs over 750 sq. ft. pay impact fees, and standard building fees always apply.
• You’ll still pay plan check, permit, school, and utility connection fees, which vary by project.

Local ADU builders typically estimate 3–5 months for design & permitting and 3–4 months for construction in the Sacramento area, depending on complexity and utility work.

Design Requirements

The County uses objective standards plus existing residential design rules:

• Exterior access: Every ADU must have its own exterior entrance.
• Separate bathroom: Attached/detached ADUs need their own bathroom; JADUs may share the main home’s bathroom but must have interior access to it.
• Compatibility: While the county doesn’t force a single style, ADUs are expected to be visually compatible with the primary home (materials, roof pitch, massing), especially in design-controlled areas.
• Stories: New detached ADUs are one story by default; additional stories require a Minor Special Development Permit.

Of course, all California Building Code and Energy Code (Title 24) requirements apply (egress windows, insulation, smoke/CO alarms, solar where required, etc.).

Utilities and Infrastructure

Sacramento County’s handout and local ADU resources stress:

• Water & sewer:
  • ADUs can often share existing service lines, but some properties will need separate connections or upsized lines, depending on district rules and capacity.
• Electricity & gas:
  • Panels must be sized for the extra load; you may keep a shared meter or add a separate meter for easier tenant billing.
• Fire sprinklers:
  • Per state ADU law, sprinklers cannot be required in the ADU unless the primary dwelling is required to have them.

Utility trenching and service upgrades can be a big part of the budget, which is why Carmichael ADU builders often evaluate utilities first in feasibility studies.

Owner-Occupancy & Renting

Sacramento County’s ADU standards and state law draw a hard line between ADUs and JADUs:

• ADUs (attached or detached):
  • The County ADU table is explicit: “Owner-occupancy [for ADUs]” is not required — only JADUs have that condition.
  • This matches AB 976, which permanently forbids cities and counties from imposing owner-occupancy requirements on ADUs approved under state law.
• JADUs:
  • By contrast, the property owner must occupy either the primary dwelling or the JADU, and a deed restriction must be recorded that limits size and prevents separate sale.

Short-term rentals

Sacramento County specifically says:

• ADUs cannot be used for short-term rental activity (under 30 days) unless they were legally permitted ADUs before January 1, 2020.
• JADUs and guest houses cannot be used for short-term rentals at all.

So in Carmichael, ADUs are effectively long-term rentals only (30+ days), but you don’t have to live on-site.

Property Taxes

Carmichael is in Sacramento County, so property tax rules follow California’s Prop 13 framework:

• The base tax rate is 1% of assessed value, plus voter-approved debt and special assessments.
• Sacramento County confirms that the applied rate is 1% + bonded debt for your tax-rate area.

When you add an ADU:

• The existing house keeps its current assessed value.
• The ADU is treated as new construction; the Assessor assigns a value (often based on construction cost), and that amount is added to your roll value.
• You’ll receive a Notice of Supplemental Assessment and likely a supplemental tax bill reflecting the new improvement.

In practice, homeowners in Sacramento County typically end up paying roughly 1.1–1.3% of the ADU’s value per year in additional property tax, once local bonds and assessments are factored in.

New ADU Laws in 2026 That Affect Carmichael

Because Carmichael is governed by Sacramento County but still in California, all recent state reforms apply here:

1. Sacramento County’s 2026 ADU Standards (effective May 21, 2026)
   • The County updated its ADU/JADU table (Table 1) and handout to reflect new height options, new multifamily allowances (up to 8 detached ADUs), and detailed deviation processes.
2. No Owner-Occupancy for ADUs (AB 976)
   • Permanently bans owner-occupancy requirements for ADUs; Sacramento County’s 2026 table reflects this by applying owner-occupancy only to JADUs.
3. Pre-Approved ADU Plans (AB 1332)
   • Requires every jurisdiction to offer pre-approved ADU plans by Jan 1, 2026; Sacramento County meets this via its Shelf Ready ADU Program, which Carmichael homeowners can use.
4. Faster, Ministerial Approvals
   • State law mandates ministerial (no hearing) review and a 60-day deadline to approve or deny a complete ADU application.
5. More Multifamily ADUs & Height Flexibility (AB 2221 and related)
   • Clarifies multifamily conversion ratios and permits up to 8 detached ADUs on existing multifamily sites, plus new height increases to 18–20 ft under specific conditions.
6. Impact Fee Limits & Street-Work Restrictions (SB 13, SB 1211)
   • Confirm that ADUs under 750 sq. ft. are exempt from local impact fees, and cities/counties can’t pile on unrelated street-widening or off-site improvements just because you’re building an ADU.

All of this makes Carmichael — as part of unincorporated Sacramento County — a very ADU-friendly place in 2026.

Carmichael ADU Laws: Key Takeaways

For a Carmichael homeowner in 2026:

• You almost certainly can build an ADU on any residential lot with a primary dwelling; Carmichael is unincorporated and fully covered by Sacramento County’s ADU standards.
• On a typical single-family lot, you can have up to three units total:
  • 1 new detached ADU (up to 1,200 sq. ft.)
  • 1 JADU (up to 500 sq. ft. inside the house)
  • 1 additional ADU (attached or conversion).
• Default rules: 16-ft tall detached ADU, 4-ft side/rear setbacks, 20-ft front setback, with options to go taller with larger setbacks or near transit.
• Parking is often waived, especially for conversions, small (<800 sq. ft.) detached units, and homes near transit; garage conversions don’t need replacement parking.
• No owner-occupancy requirement for ADUs, but JADUs require the owner to live in the main house or JADU; ADUs are long-term rentals only (30+ days).
• Property taxes rise only on the ADU’s added value, at about 1–1.3% per year of that improvement in Sacramento County.