Permit Ready ADU Plans: 20+ Verified Programs and the Catch Most Homeowners Miss

By The Dwelling Index Editorial Team — an independent research resource covering ADU financing, costs, and regulations. We are not a builder, lender, or plan seller.
Last updated: May 31, 2026 · Last verified: May 31, 2026

Permit ready ADU plans are pre-drawn building plans published or sold as ready to submit for a permit — but the catch most homeowners miss is that “permit-ready” is not a permit, and it is not the same as “pre-approved” by your own city. A stock plan you buy online (we found complete sets starting around $599) has never been seen by your building department. A city pre-approved plan has — and in California, your city must approve or deny a complete detached-ADU application that uses a current, qualifying pre-approved plan within 30 days under Government Code §65852.27. Either path, you still pull a permit and still supply a site plan, a foundation engineered for your soil, and energy calculations for your climate zone. The fastest first move is to confirm whether your city runs a program and whether your lot even qualifies before you pay anyone. See what’s possible at your address — get your free ADU report.

What are permit ready ADU plans?

Permit ready ADU plans are pre-designed plan sets for an Accessory Dwelling Unit (ADU) — a self-contained second home on a single-family or multifamily lot — that have been drawn to a building-code standard so they can move through permitting faster than a custom design. The phrase is used two very different ways: by cities for plans their building department has pre-reviewed, and by plan shops and prefab companies for finished drawings they sell. Neither version is a building permit, and a plan that is “permit-ready” in marketing language can still be rejected on your lot.

The confusion is the whole problem. When the City of Menifee, the City of Poulsbo, or Riverside County calls its program “Permit Ready ADU,” it means a building department reviewed those exact drawings and will fast-track them. When a designer on a marketplace sells you a “permit-ready” set for a few hundred dollars, it means the drawings are complete enough to submit — but your city has never seen them, and they were almost certainly not engineered for your soil, your seismic or wind zone, or your climate zone’s energy code.

Maxable, an ADU planning service, frames the core misconception well: a pre-approved plan is not the same as a pre-permitted one — your planning department still needs to know how the ADU sits on your property, how it connects to utilities, and how it interacts with surrounding structures before any permit is issued (Maxable, verified May 2026).

Permit-ready vs. pre-approved vs. pre-permitted vs. standard — decoded

There is no single national vocabulary, which is exactly why this query is so confusing. Here is what each term actually signals.

Plain-English definitions used throughout this guide. A DADU is a detached ADU (a standalone backyard cottage). A JADU (junior ADU) is a unit of 500 sq ft or less created within an existing home, usually with owner-occupancy strings. Plan check is the city’s review of your drawings. A site plan (or plot plan) shows where the ADU sits on your lot, with setbacks and utilities. A setback is the required distance from a structure to a property line. Title 24 is California’s building energy-efficiency code; the CF-1R is its compliance form. A utility lateral is the pipe or line connecting your unit to the public water, sewer, or power main. Ministerial approval means the city must approve a compliant application by objective standards, without a discretionary hearing. Impact fees and system development charges (SDCs) are one-time fees on new units that fund infrastructure.

One legal nuance worth knowing: California’s law requires cities to post pre-approved plans and the applicant’s contact information online, but states that posting “is not an endorsement” of the applicant and is not approval of any specific detached-ADU application (Gov. Code §65852.27, verified at leginfo.legislature.ca.gov, May 2026). The plan being listed does not mean your project is approved.

The damaging admission, said up front: “permit-ready” is one of the most overused phrases in the ADU world. A set of drawings can be technically permit-ready and still be useless to you — if your city won’t accept it, or if your lot forces structural changes that throw out the fast-track. The good news is that this is entirely knowable before you spend money, and the rest of this guide shows you exactly how to check.

The 4 ways to get ADU plans — and which one fits you

There are four realistic ways to get plans for an ADU: buy a stock “permit-ready” set, use your city’s pre-approved program, hire a designer for a custom set, or buy a prefab/modular unit where the design is bundled. They differ most on three things — how much your lot deviates from a standard rectangle, how much you intend to customize, and who carries liability for pulling the permit. A city pre-approved plan is usually fastest and cheapest where it exists and fits; a custom set is the safest path for complicated lots; prefab folds the design into the product.

The matrix below is sorted by typical upfront plan cost, lowest to highest. Every figure is sourced and dated in the cost section.

Path A — Buy a stock “permit-ready” plan

Stock plans are the cheapest entry point — we found complete ADU sets starting around $599 on one online plan marketplace (verified May 2026). But a stock set is drawings, not a project. Even a reputable plan still needs a designer to finish a submittable package for your jurisdiction; off-the-shelf plans still require local adaptation, structural work for your soil, and Title 24 for your climate zone (SnapADU, verified May 2026). If you go this route, vet the seller on whether the set includes structural calculations, whether it can be stamped in your state, and what local adaptation it will still need.

Path B — Use your city’s pre-approved program

This is the path most people are actually looking for, and where it exists and fits your lot, it is usually the best value — frequently free, and dramatically faster. The catch is availability and fit, which is what the finder below resolves.

Path C — Hire a custom designer

A full custom permittable set runs roughly $5,000–$20,000 in California, and higher in coastal, hillside, or HOA-restricted situations. It’s the right call when your lot or use case can’t be served by a standard plan — and, as we’ll show, a bad-fit pre-approved plan can actually end up slower than a clean custom design.

Path D — Go prefab or modular

With prefab and modular ADUs, the design is typically bundled into the unit price, so “plans” aren’t a separate line item, and the factory build can run in parallel with your local permitting. Prefab does not eliminate local approvals — you still need a site plan, foundation, and utility connections — but it can compress the overall timeline.

Does your city have a permit-ready / pre-approved ADU plan program?

Whether a program exists depends almost entirely on your state. California requires every city and county to run a pre-approval program under AB 1332 (since January 1, 2025). Arizona, Oregon, and Maine passed laws in 2025; Colorado funds programs through grants; Vermont is piloting a statewide catalog; and Washington, Tennessee, New York, Pennsylvania, and Hawaii introduced bills in early 2026. As of 2026, roughly 40 U.S. jurisdictions run some form of pre-approved building-plan program — and even where one exists, quality ranges from a rich free catalog to a thin PDF. That last point matters: California’s law lets a city “comply” with as little as an online list of green-lit designs, so “a program exists” does not guarantee free, ready-to-use plans.

The table below is our Permit-Ready ADU Plan Finder (v1) — assembled from official city, county, and state sources and verified in May 2026. The Scope column matters more than it looks — the single most common mistake is confusing a city program with its county program, which are often entirely separate (Riverside is a perfect example below). Each row links to its official source.

Beyond this list, Pew’s 2026 national survey counts roughly 40 jurisdictions with pre-approved building-plan programs — including non-ADU and multi-unit catalogs in places like South Bend (IN), Jackson (MI), Hawaii County (HI), and Claremore (OK). We’re adding verified ADU rows quarterly (Renton, Ashland, Bend, Salem, Kirkland, Cupertino, San Diego City & County, and others), each with its own source and verification date.

California — what AB 1332 guarantees (and the loophole)

Under AB 1332, codified at Government Code §65852.27, every California local agency had to develop an ADU plan pre-approval program by January 1, 2025, post the plans online, and approve or deny a complete detached-ADU application built on a qualifying pre-approved plan within 30 days. The California Building Officials association (CALBO) notes the catch in plain terms: a city can satisfy the law with an online database of plans or simply a PDF of designs it has green-lit (CALBO, verified May 2026). So in California the question isn’t “does my city have a program” — by law it does — but “does my city’s program have usable, current plans for my lot.”

Washington, Oregon, Idaho & the rest of the West

Outside California, the strongest programs are concentrated in the Pacific Northwest. Seattle’s ADUniverse program offers seven pre-approved detached designs, and the city’s reports show pre-approved plans cut average ADU approval time from 160 days to 54 days — a 2.6× reduction (The Pew Charitable Trusts, May 2026). Oregon built a shared model: Eugene developed plans and gave them to Portland at no cost, with similar plans in use in Bend and Salem (Portland.gov, verified May 2026). And the trend is moving inland — Boise launched eight free pre-approved plans (280–695 sq ft) in March 2026, with the city noting a custom design can run “upwards of $10,000” (cityofboise.org, verified May 2026).

The 2025–2026 wave: AZ, ME, VT, CO, and bills to watch

A May 2026 report from The Pew Charitable Trusts maps the national picture: California acted first statewide; Arizona, Oregon, and Maine passed pre-approved-plan laws in 2025; Vermont is piloting its “802 Homes Catalog”; and Colorado funds pre-approved plans through “ADU Supportive Jurisdiction” grants (HB24-1152). Pew also reports that Washington (statewide), Tennessee, New York, Pennsylvania, and Hawaii introduced pre-approved-plan bills in early 2026. If you’re outside the West Coast, search your city’s building or planning department site for “ADU,” “pre-approved,” “standard,” or “permit-ready” plans.

No program near you? Here’s what to do instead

If your city has no usable library, you still have three solid paths: a semi-custom designer set for a simple lot, a prefab/modular unit in a prefab-friendly area, or a full custom design for a complex site. One thing you generally cannot do is grab another city’s free plan and assume your city will fast-track it — even where an agency could adopt outside plans, you still need your own jurisdiction to accept it for your address. The smartest first step in any of these cases is the same: confirm what your lot can actually hold.

For more on specific city programs, see: City of San Diego ADU plans, San Diego County pre-approved ADU plans, San José pre-approved ADU plans, Chula Vista pre-approved ADU plans, Encinitas PRADU plans, Carlsbad permit-ready ADU status, and El Cajon pre-approved ADU plans.

Are permit ready ADU plans actually free?

Sometimes. Many city-owned plan sets are genuinely free — Concord, Boise, Citrus Heights, Richmond, and Los Angeles County all publish no-cost plans. But “free plan” means free base drawings, not a free project: private-designer plans carry a license fee, some “free” plans come with strings, and every path still requires a paid site plan, foundation engineering, utility plans, and permit fees. Treat “free” as “free design,” not “free permit.”

Free city plans — and the strings some carry

Where a city owns the plans outright, the design fee disappears. Concord, California offers six free, code-compliant plan sets (about 200–900 sq ft) funded by a state housing grant (cityofconcord.org, verified May 2026). Boise’s eight plans are free; Citrus Heights’ three models came from a state LEAP grant; and Los Angeles County’s County Catalog plans are free to download. But read the fine print: the City of Piedmont waives ADU permit fees if you use a city-designed plan — on the condition that, if you rent the unit, it must be affordable to very-low-income households (piedmont.ca.gov, verified May 2026). A free plan with a multi-year rent restriction is a very different deal than a free plan with no strings.

Paid designer or vendor plans

When the designer owns the plan, you license it. Seattle’s program is explicit: paying the plan fee buys you the right to use that design one time, in one location — industry-standard for any purchased or custom design (Haas Building, verified May 2026). Los Angeles’s LADBS program is mostly privately owned plans: only the city’s own YOU-ADU plan is free, while other Standard Plans must be purchased from the plan owner (dbs.lacity.gov, verified May 2026).

What do permit ready ADU plans really cost — by path?

A stock plan starts around $599 (drawings only); a city pre-approved plan is often free or a one-time designer license; a full custom permittable set runs about $5,000–$20,000 in California; and prefab folds the design into the unit price. A 2026 Pew analysis found pre-approved-plan programs reduce a builder’s overall development cost by about 1%–2% — roughly $5,000–$10,000 on a $500,000 project — primarily by cutting design and approval costs. The figure that surprises people most: the site-specific work that applies to every path usually runs several thousand dollars on its own.

How much do you actually save with a pre-approved plan? Estimates vary by who’s counting. The neutral, multi-program figure from Pew is about 1%–2% of total project cost ($5,000–$10,000). Builder estimates land in a similar-to-wider band: GatherADU estimates $3,000–$5,000; and one San Diego firm cites $8,000–$25,000 in design-fee savings versus a fully custom design. We present these as attributed estimates, not a promise — your actual savings depend on your city and lot.

Why “free” still isn’t free: a no-cost city plan removes the design-and-review cost. It does not remove site preparation, the foundation engineered for your lot, utility laterals, the permit and plan-check fees, or construction itself — which is where the vast majority of an ADU’s all-in cost lives.

If you’re weighing how to fund construction, see our independent breakdown of ADU loan lanes in Best ADU Financing Options.

What do permit ready ADU plans still NOT include?

A pre-approved or stock plan covers the ADU building. Your permit package still needs property-specific work: a site plan, a foundation engineered for your soil and seismic zone, Title 24 energy calculations for your climate zone, often solar PV plans, sometimes a stamped truss design and soils report, plus separate electrical/plumbing/mechanical permits, utility connections, and possible impact or system-development fees. Local design firms describe these plans as roughly 80–85% complete — the owner fills in the project-specific remainder. Budget several thousand dollars and a few weeks for that site-specific layer no matter which plan you choose.

Even the most complete city programs are explicit about this. Richmond, California’s pre-approved sets include architectural, structural, MEP, and a Title 24 report — and the city still requires the homeowner to provide a cover sheet, a site-specific plan, and a foundation design (richmondca.gov, verified May 2026). Portland lists zoning, utility connections, flood-hazard checks, separate trade permits, and possible SDCs as remaining items (Portland.gov, verified May 2026). Santa Clara County requires the owner to supply Title 24 (CF-1R) forms, solar PV plans, and a truss design stamped by the manufacturer’s engineer (santaclaracounty.gov, verified May 2026).

How much time do permit ready ADU plans actually save?

The savings are real but conditional, and they come from two places: skipping months of custom design, and a faster, often-discounted plan review. Verified review timelines on pre-approved plans range from same-day issuance in San José, to 5 working days in Concord, to a 3-business-day first review in the City of Riverside, to a 30-day statutory clock in California, to Seattle’s 160-days-to-54-days reduction. None of these clocks shorten construction, site work, or utility upgrades. And every “fast” timeline assumes a complete, accurate package — incomplete site documents drop you back into the standard queue.

Where the savings come from: fewer custom design hours, less back-and-forth on base building details, a dedicated or expedited review lane, and often a plan-check fee discount. Where they don’t: construction labor, site preparation, foundation work, utility connections, permit fees, change orders, and financing carrying costs. The honest framing: a pre-approved plan can shave weeks-to-months off the front of your timeline, but the build itself — commonly 4–12 months for a detached ADU — is unchanged.

Can you modify a permit-ready ADU plan?

Usually only within the narrow options a program allows — exterior finishes, roof style, color, and mirroring (flipping) the layout are commonly permitted. Moving walls, relocating a bathroom, adding a bedroom, or changing the foundation typically removes the plan’s pre-approved status and sends it through full plan check. Several cities state outright that no structural or layout modifications are allowed. If you want meaningful design changes, a custom or semi-custom plan is often the better path from the start.

The official language is blunt, because it’s where people get burned:

• Concord, CA: the pre-approved design “cannot be revised and must be permitted as designed.” You may mirror it and orient it any direction; changes require a separate, non-expedited permit (cityofconcord.org).
• Richmond, CA: designs “cannot be revised”; orientation and mirroring may be allowed, and any change request needs a written statement and may be denied (richmondca.gov).
• Colma, CA: “no customization beyond materials” for the expedited 30-day review (colma.ca.gov).
• Sacramento County, CA: outside adding a few electrical receptacles/lights, the plans can’t be modified beyond the floor-plan options provided, and the roof trusses can’t be altered at all (saccounty.gov).
• Poulsbo, WA: allows roof style, siding, color, windows, and doors — but other modifications “may disqualify pre-approved status” (poulsbo.gov).

Permit-ready vs. prefab vs. custom: which path fits your lot?

Choose a city permit-ready plan when your local program is active and a plan fits your lot with minimal change; choose prefab/modular when a provider has a real code path and installation support in your area; choose custom when your lot, zoning, utilities, or design needs are too specific for a standard plan. The deciding variable isn’t price — it’s fit. A plan that doesn’t match your lot will cost you the very speed and savings that made it attractive.

• Housing aging parents: prioritize a no-step entry, an accessible bathroom and circulation, bedroom privacy, and caregiver access. Several programs offer an accessibility-oriented option (Citrus Heights’ plans include wider doorways and hallways; the Kitsap/KRCC plans were designed with 36-inch doors and accessible baths).
• Rental income: prioritize bedroom count, entry/parking separation, durable finishes, and a clear utility-metering strategy. Illustrative example only: in high-demand markets a two-bedroom ADU can command premium rent. These are illustrative examples, not guarantees of returns. Actual results depend on local market conditions, construction costs, financing terms, and regulatory approvals.
• Moving quickly: pick the plan with the fewest site exceptions, not the cheapest file — the package that clears review without correction letters wins.
• Complex lot (slope, coastal, historic, WUI): lean custom; a pre-approved plan will likely fail or require so many changes it loses its advantage.
• Garage conversion: confirm availability — most pre-approved libraries are detached-only (Lake Elsinore’s 400 sq ft conversion plan and Piedmont’s 484 sq ft conversion are exceptions).

The damaging admission for this decision: a bad-fit permit-ready plan can be slower than a clean custom design. If you have to modify the structure, foundation, roofline, or utility assumptions, you forfeit the expedited review — and you may have paid for a plan you now have to substantially redraw.

How do California’s AB 1332 pre-approved ADU rules actually work?

California is unusually important for this query because state law forces the issue. Government Code §65852.27 (added by AB 1332) requires every local agency to run an ADU plan pre-approval program and to approve or deny a complete detached-ADU application that uses a qualifying pre-approved plan from the current code cycle within 30 days. Separately, AB 130 restricts new, more-restrictive residential building standards from October 1, 2025 through June 1, 2031. Neither law means every city gives away free plans, and neither means a given plan works on every lot.

The three conditions people miss

The 30-day clock isn’t automatic. Reading §65852.27 alongside CALBO’s guidance, it applies only when all three hold:

1. It’s a detached ADU (the statutory fast-track is detached-specific).
2. Your application is complete (including the site-specific items above).
3. The plan was pre-approved within the current triennial California Building Standards Code cycle — or is identical to a plan approved during that cycle.

Miss any one, and you’re back on the standard timeline (still typically 60 days, but without the guarantee).

Why code-cycle status matters — the Santa Barbara warning

A pre-approved plan can go stale. The City of Santa Barbara’s program is currently paused: its page states the displayed plans “are not eligible for permitting due to updates in the 2025 construction codes,” with new compliant plans in progress (santabarbaraca.gov, verified May 2026). Los Angeles County’s Private Designer Catalog has the same issue from the other direction — those plans “need to be updated to comply with new building code requirements that went into effect on January 1, 2026” (planning.lacounty.gov, verified May 2026). Always check that a plan is current under today’s code before you pay anyone to adapt or submit it.

Why “posted on the city website” isn’t approval

As noted earlier, §65852.27 requires cities to post pre-approved plans and the applicant’s contact information, but specifies that posting “is not an endorsement” of the applicant and is not an approval of any specific detached-ADU application (leginfo, verified May 2026). The plan being listed gets you a head start — it does not get you a permit.

How to use a permit-ready ADU plan without wasting money

Don’t start by buying a plan. Start by confirming your jurisdiction, your lot’s eligibility, the plan’s current-code status, and the site-specific documents required — then choose your plan path. Ordering it this way prevents the most common and expensive mistake: paying for plans before learning your lot can’t use them.

1. Confirm your jurisdiction. Confirm which city or county actually permits your property — city vs. unincorporated county changes everything, and they often run separate programs.
2. Search the building/planning department. Search that building/planning department’s site for “ADU,” “pre-approved,” “standard,” or “permit-ready” plans.
3. Confirm current code-cycle status. Confirm the plan is active under the current building-code cycle (the Santa Barbara and LA County lesson).
4. Verify your lot’s eligibility. Ask whether the plan applies to your zoning, lot type, overlays, and ADU type.
5. Get the submittal checklist in writing. Get the city’s submittal checklist in writing.
6. Confirm site-specific drawings required. Confirm exactly which site-specific drawings you must supply: site plan, foundation, Title 24, solar, utilities.
7. Ask about modifications and strings. Ask whether any modification removes expedited status — and whether a “free” plan carries rent or affordability strings.
8. Get a written fee estimate. Get a written fee estimate, including impact/SDC fees if your ADU exceeds 750 sq ft.
9. Hire the right professional. Hire the right professional for the remaining items — a designer, civil/structural engineer, or contractor.
10. Submit a complete package. Submit only after the package is complete and accurate — this is what unlocks the fast review clocks.

What should you ask your city before choosing a permit-ready plan?

Before paying anyone to adapt or submit a plan, ask your city whether that specific plan is currently accepted, current under code, eligible on your lot, and eligible for expedited review. Five minutes on the phone can save months and thousands of dollars. Cities answer these questions for free; designers and builders may not volunteer the caveats.

What if my city doesn’t have permit-ready ADU plans?

If your city has no active library, you have four options: a semi-custom designer set for a simple lot, a prefab or modular unit in a prefab-friendly area, a full custom design for a complex site, or — only if your city explicitly accepts it — a plan from another jurisdiction. The right choice depends on your lot’s complexity and your budget, and the cheapest first step is always to verify what your lot can hold.

Methodology: how we built this permit-ready ADU plan finder

We built this guide official-source-first. Program facts, plan counts, sizes, free-vs-paid signals, and caveats come from city, county, and state pages and primary statutes, each recorded with a verification date. We used homeowner forums only to identify common questions and friction points — never as proof of laws, fees, timelines, or approval rules. Editorial conclusions (which path may fit which buyer) are clearly separated from verified facts, and we recommend confirming all program details with local planning and building staff before spending money.

• Each finder row records scope, program status, plan count/size, free-or-paid signal, the key catch, and the official source, with a verification date.
• Where an official page is incomplete or a program is in flux, we say so rather than guess.
• Cost figures are presented as ranges with attributed sources; estimates are labeled as estimates.
• Partner links are never used as evidence of code or approval, and comparison tables are sorted by neutral criteria (cost, size, timeline), never by compensation.
• We re-verify the top jurisdictions monthly and the full finder quarterly.

Permit ready ADU plans: FAQ