Inside Carlsbad's city limits the City's Building Division, at the Faraday Avenue permit center, issues the permit for an ADU, a remodel, an addition or a new house, and in the Coastal Zone the Planning Division decides the coastal permit most new detached ADUs need, without a hearing. The City Council rewrote the ADU section of the Zoning Code on February 3, 2026: the one-story limit on a detached ADU is gone, no ADU may carry a roof deck, and the units state law makes every city approve are taken as the statute lists them. That text is in force outside the Coastal Zone and waits on the Coastal Commission inside it. The four free permit-ready plans are offline for the 2025 codes, and every new detached ADU comes with solar panels.
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BHI Builders takes on ADUs, remodels, additions and custom homes in Carlsbad, where an ordinance of February 2026 rewrote the ADU rules and lots inside the Coastal Zone wait on the Coastal Commission's word. The rules below come from Carlsbad's own documents and the state law behind them.
Who issues permits here, and how does plan check run?
The City of Carlsbad's Building Division issues building permits inside the city limits from the permit center on Faraday Avenue, open weekdays from 8 am to 5 pm, with its own phone lines for permits and for inspections. Some simple permits with no plan check are filed in the City's online self-service portal with no appointment; a full plan set, such as an ADU, still comes in through the Building Division on the residential application form, which the contractor or the owner signs.
The City puts a first plan check at about 10 to 15 working days and each resubmittal at 5 to 8, and a plan check stays open for one year from submittal, corrections and resubmittals repeating until every reviewer has cleared the set. For an application that is only an ADU or a junior ADU, the bulletin and the code add the state's clocks: the City says within 15 business days whether the application is complete, and approves or denies within 60 days of a complete one unless you ask for more time.
Four desks read an ADU: Planning, which checks the zone, the overlays and the Coastal Zone; Building; Land Development Engineering, for grading, the right of way and storm water; and Fire and Life Safety. In the Coastal Zone the minor coastal development permit is filed with Planning by appointment and has to be approved before or together with the building permit; neighbours get a notice, written comments run for 10 days, and the City Planner decides 10 days after the notice, with no hearing. Inspections are booked by phone before 2 pm for the next working day, between 8 am and 4 pm, with an adult on site.
The residential submittal checklist, dated July 2025, lists what the set holds: the title sheet and a site plan, the construction drawings, grading plans where grading needs a permit, a single line diagram when the service is over 200 amps, structural and truss calculations, the soils report where one applies, the energy forms, a boundary certification for a new foundation within 5 feet of a property line, and the Climate Action Plan checklist for new construction. The permit-ready checklist asks for more that a custom ADU is wise to bring too: a current grant deed and a title report under six months old, the housing tracking form, a construction waste plan filed in the City's recycling system before issuance, an SDG&E work order before issuance when the panel is upgraded, and the ADU notice of restrictions, which Planning prepares after submittal and which is recorded before the permit issues.
Work on site runs weekdays from 7 am to 6 pm and Saturdays from 8 am to 6 pm, never on a Sunday or a federal holiday, and 65 percent of the construction debris has to be recycled, with the receipts shown before final. The City builds to the 2025 California codes, adopted on December 2, 2025 and in force since January 1, 2026, in seismic design category D, climate zone 7, with a design wind speed of 96 miles an hour.
For the projects homeowners bring most often:
- An ADU or junior ADU: a building permit, approved without a hearing on the 15-day and 60-day clocks above, plus a minor coastal development permit for a new detached unit in the Coastal Zone; a garage you take down for it is permitted in the same review.
- A kitchen or bath remodel that moves plumbing, wiring or walls: a building permit through the Building Division, with the climate checklist once the job's valuation passes the City's threshold for alterations.
- An addition or a second story: the zone's height, 30 feet in R-1 with a roof pitched at 3:12 or more and 24 feet with a flatter roof, 40 percent lot coverage, school fees paid to the district first, and between the railroad and the sea a site development plan under the Beach Area Overlay.
- A new house: full plans, a coastal development permit in the Coastal Zone, a hillside permit on a slope of 15 percent or more with 15 feet of rise, the 2025 Wildland-Urban Interface Code's construction in a high or very high fire zone, and Engineering's grading and storm water review.
Where do Carlsbad's ADU rules differ from state law?
The City Council introduced Ordinances CS-506 and CS-507 on January 27, 2026, each 5 to 0, and adopted them on February 3, 2026, rewriting section 21.10.030 of the Municipal Code for the state's 2024 bills after a six-week public review in late 2025 that drew no comment and the Planning Commission's recommendation of November 19, 2025. The section now defers to the Government Code for how many units a lot gets and where, drops the one-story limit on a detached ADU, bars roof decks on attached and detached ADUs alike, and says that a reference to the Government Code means the statute as amended, so the 2025 bills apply without another rewrite.
Outside the Coastal Zone the new text took effect 30 days after adoption. Inside it, the ordinance is also a Local Coastal Program amendment that takes effect only when the Coastal Commission certifies it, and the City's code host still marks it pending; until then the earlier certified text governs on coastal lots, as state law provides. The City's bulletin IB-111, reissued in August 2026, was not rewritten to the ordinance or to the 2025 bills: it keeps the one-story limit, names only the detached roof deck, and lists no bill after January 2025. The table follows the code and the statute, and the list after it says where the bulletin differs.
| Rule | In the City of Carlsbad |
|---|---|
| Units on a single-family lot | One attached or detached ADU, plus the units state law makes every city approve: a unit converted from existing or planned space, with up to 150 square feet added for its door, a junior ADU, and one new detached ADU of up to 800 square feet with 4-foot side and rear setbacks that may stand in the front setback when nothing else fits 800. The bulletin sums it up as two ADUs and a junior ADU. The house has to exist or be built at the same time, and there is no minimum lot size. |
| Multifamily and two-family lots | Conversions of non-living space in an existing building, at least one unit and up to a quarter of the existing units. Detached units: outside the Coastal Zone, up to eight on a lot with an existing multifamily building and two with a planned one, never more than the number of existing units; inside the Coastal Zone the bulletin allows two until the Commission certifies the new text. Two detached ADUs may share a wall, and a condominium's common area needs the association's authorization. |
| Size | A new attached ADU up to half the house's floor area or 1,200 square feet, whichever is less, and never held under 800; a conversion the size of the space it fills plus 150 square feet; a detached ADU up to 1,200 square feet, as far as lot coverage allows; a junior ADU 500. Lot coverage counts a detached ADU over 800 square feet, and an attached one over 800 square feet and over 16 feet. |
| Height | A detached ADU 16 feet, with no limit on stories since February 2026; 18 feet within half a mile's walk of Carlsbad Village Station or Poinsettia Station, or of a high-quality transit corridor, and 2 feet more for a roof pitched to match the house, 20 at most; 18 feet on a lot with a multistory two-family or multifamily building. An attached ADU up to 25 feet or the zone's limit, whichever is higher, never more than two stories. A unit above or below a detached garage takes the zone's height, one story over the garage and two in all. The City's transit maps draw the half-mile circles. |
| Setbacks | Four feet from the side and rear lines; the zone's front setback, unless that would stop an 800 square foot unit. A nonconforming garage or accessory building converted to an ADU keeps its setbacks, except in the Coastal Zone where the nonconformity touches a geologic setback, a public view, coastal access or a habitat buffer. A new ADU may take the setbacks of a lawfully demolished building it replaces in the same place and size. A garage, patio cover or deck that is not part of the ADU keeps the zone's setbacks. |
| Design | Roofing, trim, walls, windows and the colour palette match the house, or the nearest building on a multi-unit lot; none of this applies to the units state law makes the City approve. No roof deck on any ADU, attached or detached. A separate outside door, and the state's efficiency-unit construction standards. In the Coastal Zone the unit also keeps to the Local Coastal Program's habitat buffers, geologic setbacks and view policies. |
| Solar and sprinklers | A new detached ADU includes a solar photovoltaic system unless the system already on the lot has the capacity to serve it, and the permit-ready checklist points to the Energy Code's photovoltaic rules. Fire sprinklers only where the house itself had to have them when it was built. |
| Parking | One space, covered or uncovered, tandem on the driveway or inside a setback. None within half a mile's walk of the two train stations or a bus stop, in a historic district, for a unit inside the house or an accessory building, within a block of a car share, or where street permits are required but not offered to the unit. Parking lost to an ADU is not replaced, except on lots west of the rail corridor and on lots between the railroad and Interstate 5 from Avenida Encinas south to Batiquitos Lagoon, where a replacement space may be covered, uncovered, tandem or on a lift in any yard. |
| Junior ADU | One per single-family house, inside its walls or an attached garage, up to 500 square feet, with its own entrance, an efficiency kitchen, no parking and no separate water, sewer or power connection required. It may share a bathroom with the house, and then needs a door into the house and the owner living in the house or the unit. A deed restriction barring a separate sale is recorded before the permit issues. |
| Owner occupancy | No ADU requires it. A junior ADU asks the owner to live on the lot only while the unit shares the house's bathroom. |
| Rentals | Only under a lease for a term longer than 30 days; the bulletin's "at least 30 days" is one day short of the statute. An ADU or junior ADU permitted since January 1, 2020 cannot be a short-term vacation rental anywhere in the city, and the City allows such rentals only in the Coastal Zone and the La Costa resort area in any case. |
| Selling a unit on its own | A junior ADU, never. An ADU only as the Government Code allows: to a qualified buyer when a qualified nonprofit built it, under a recorded tenancy in common with 45 years of affordability. The City has not adopted the ordinance that would let an ADU be sold as a condominium, and its bulletin says it permits no separate sale; the code points to the statute, which governs. |
| Nonconforming conditions | The City does not make you fix a nonconforming condition as the price of an ADU, with one exception written in 2026: an ADU in the Coastal Zone attached to a house that is nonconforming on a geologic setback, a public view, coastal access or a habitat buffer, where the work replaces half or more of the structure. |
| Units built without a permit | An ADU built before January 1, 2020 is permitted unless health and safety require otherwise, as the statute provides. |
| Water and sewer | Adequate water and sewer service has to be available under the City's engineering standards, though upgrades to the existing service may not be required. The permit-ready checklist warns that a new 4-inch sewer lateral may be needed and sends you to your sewer district, since three water districts and three sewer agencies serve the city. |
Where the bulletin still reads differently from the code or the statute:
- Stories. The bulletin limits a detached ADU to one story; the code as amended in February 2026 sets 16 feet and no story limit.
- Roof decks. The bulletin bars them on detached ADUs; the code bars them on attached ADUs too, and neither rule may be applied to a unit state law makes the City approve.
- The rental term. The bulletin's 30 days for an ADU and 31 for a junior ADU against the statute's "longer than 30 days"; a lease of 31 days or more satisfies both.
- The fee line. The bulletin exempts an ADU "less than 750 square feet" from impact fees; the statute exempts 750 square feet or less, so a unit of exactly 750 pays none.
- Detached units on a coastal multifamily lot. Two under the bulletin and the certified text, eight under the code and the statute once the Commission certifies the amendment.
- The minor coastal permit. The bulletin says every ADU in the Coastal Zone takes a minor coastal development permit, and the City's 2024 and 2026 notices process detached ADUs that way; the permit form itself draws a line at a construction cost above which a project takes a full coastal development permit. Ask Planning at intake which path your unit takes.
Can you build from a pre-approved ADU plan here?
Not today. Carlsbad's Permit Ready ADU program offers four single-story detached plans in three styles, a studio and one, two and three bedrooms from 400 to 1,000 square feet, drawn after a 2022 survey of residents, presented to the Council in May 2023 and paid for with a state planning grant. The plans are pre-checked under the building code, so a permit from one is processed faster and pays a lower plan check fee, and any change to the drawings loses both. Since the 2025 codes took effect the plans have been offline while the City updates them; on October 27, 2026 its page still said they were expected back by summer 2026.
When they return, a permit-ready plan is still a building permit application: the plan set, the checklist, a hold harmless agreement and the residential form, plus the minor coastal permit forms in the Coastal Zone, read by Planning, Building, Engineering and Fire. The checklist asks for the lot's zoning and overlays, its Coastal Zone status, the floor areas and lot coverage, the parking space or the exemption claimed, the heights measured the City's way, the solar system, any SDG&E panel upgrade, the utility connections with their distances, and a geotechnical report for a unit near a slope or on a bluff. Through 2024 the program had three applications and two approvals.
Coastal, beach, hillside, fire and historic rules
Much of western Carlsbad is in the Coastal Zone, and the City's map sorts it three ways: where the City issues the coastal development permit, where it issues one the Commission could appeal, and the Agua Hedionda Lagoon segment, where the Commission itself issues the permit because that part of the Local Coastal Program was never fully certified. An attached ADU, a unit converted from the house or an attached structure, and a junior ADU are improvements to the house that need no coastal permit, even where the house is nonconforming on a habitat buffer or a geologic setback; a new detached ADU does. Since October 2025 a coastal permit for an ADU alone can no longer be appealed to the Commission, and the decision clock is 60 days.
Coastal lots carry two more layers. The Coastal Resource Protection Overlay covers every coastal property: a slope of 25 percent or more gets a slope map and analysis, such a slope with sensitive habitat is kept, with at most a 10 percent encroachment where the rule would otherwise leave no reasonable use, and any other steep slope is graded only on findings that include an engineer's 75-year stability opinion. Between the railroad and the ocean, from Buena Vista Lagoon to Agua Hedionda Lagoon, the Beach Area Overlay issues no building permit without an approved site development plan and holds buildings to 30 feet with a 3:12 roof or 24 feet below it; whether that plan is asked of an ADU, which the code approves ministerially when it meets its own section, is a question for Planning before you draw.
On a slope of 15 percent or more with more than 15 feet of rise, nothing is graded or built without a minor hillside development permit or a hillside development permit, unless the work is on a manufactured slope already graded under a permit and meets the hillside guidelines; the permit-ready checklist asks for a geotechnical report for any detached ADU near a slope or on a bluff, and for every detached unit over 750 square feet.
For fire, the City adopted the State Fire Marshal's map of March 24, 2025 by Ordinance CS-495 in June 2025, so the moderate, high and very high zones in the Municipal Code are that map's, a structure under two zones taking the stricter. In a very high zone a new house or ADU is built to the ignition-resistant chapter of the 2025 Wildland-Urban Interface Code, keeps 100 feet of defensible space, and takes the state's Zone Zero rules on new construction; in a high zone the ignition-resistant construction and the sale disclosure apply without the defensible space rule; in a moderate zone nothing more. The Fire Department's address map shows your zone. The 2025 Fire Code and the Wildland-Urban Interface Code were adopted on December 2, 2025, with the vegetation work finished before the building permit's final.
Historic review is narrower than in the City of San Diego. Carlsbad designates a resource under its own Title 22 when a building is at least 50 years old and meets one of its criteria, and once a designation is applied for, work on that building stops for 90 days unless its permit was already issued. The City's own answer on CEQA is that a ministerial approval is not subject to it, so an ADU or a garage conversion on an undesignated lot gets no age-based review; a designated house, or one with a designation pending, is another matter, and the Mills Act and the Historical Building Code are there for it.
Carlsbad's Climate Action Plan ordinances of March 2019 are what apply to a new building: a new detached ADU fills in the solar, water heating and electric vehicle charging sections of the climate checklist, and an alteration under the valuation threshold fills none. The Council adopted the plan's 2024 update without the reach code measures, so there is no all-electric rule.
Which fees apply, and where are the schedules?
Carlsbad prices its permits in one Master Fee Schedule: the edition for the fiscal year that began July 2026 was approved by the Council on June 16, 2026 and took effect on September 1, 2026, and it holds the plan check, building permit, minor coastal permit and connection fees. The City's ADU page puts the permit cost of most ADUs in a band that depends on the unit's size and says many ADUs pay no impact fee at all because they fall under the size line.
- Impact fees. None on an ADU of 750 square feet or less of interior living space, including every junior ADU. Above that, a share of the fee a new house would pay, in proportion to the ADU's size against the house's; the bulletin's example is half the fee for a 1,000 square foot ADU beside a 2,000 square foot home. On a multi-unit lot the comparison is with the average unit.
- School fees. Carlsbad Unified sets a rate per square foot of new residential space, last approved by its board on April 15, 2026, and charges none on construction under 500 square feet; the fee is paid at the district office before the City issues the permit. San Marcos Unified, which serves the east of the city, charges on new residential space of 500 square feet or more, ADUs named. Parts of the south are in the Encinitas and San Dieguito districts.
- Water and sewer. Three water districts serve the city, Carlsbad Municipal Water District in most of it, Olivenhain in the south east and Vallecitos in the east, and the south is sewered by Leucadia Wastewater District or Vallecitos, so the connection and capacity charges depend on where the lot sits. A conversion of existing space pays no connection fee or capacity charge; a new unit may need a new connection, charged by its size or its fixtures, unless it is built with a new house. The water district's rates stepped up on July 1, 2025 and January 1, 2026 and step again on January 1, 2027.
- Sewer Benefit Area N. On May 12, 2026 the Council created a new sewer benefit area with its own capacity fee for new development in the Village, the Barrio and the streets around them. Whether it is charged to an ADU, and how the state's fee rule limits it, is a question to put to the counter.
- Everything else. The housing tracking form and the recorded notice of restrictions at submittal, the waste plan before issuance, and the fire hazard disclosure inspection only when a house in a high or very high zone is sold.
How many ADUs Carlsbad permits
Carlsbad reports its ADU building permits to the state every year: 33 in 2018, between 50 and 82 a year since 2020, and 77 in 2025.
- 332018
- 332019
- 502020
- 742021
- 812022
- 822023
- 572024
- 772025
What Carlsbad reported to HCD as ADU building permits issued, by the year it reported them (Table A2, ADU category), not units completed; junior ADUs have no category of their own on the state's form. The City's own reports give the same 82 for 2023 and 57 for 2024, and count 46 and 67 ADUs completed in those years.
Recent changes in Carlsbad
What has changed in the City's permit rules since 2024, newest first.
Outside the Coastal Zone, Carlsbad's February 2026 ordinance reads the statute's unit list as written, so AB 956's second detached ADU applies directly; on coastal lots, still under the older certified text, each new detached unit also needs Planning's minor coastal development permit. More in the 2027 guide.
The Master Fee Schedule for the new fiscal year took effect, approved on June 16, 2026, and a yearly permit fee began for short-term vacation rentals, which an ADU permitted since 2020 cannot be.
The August 2026 edition of bulletin IB-111 was posted, still describing the bills through January 2025 and the one-story limit the February ordinance removed.
The Coastal Commission issued its guidance on ADU amendments to local coastal programs, explaining AB 462's end to Commission appeals of ADU-only coastal permits and what governs a coastal lot while an amendment waits for certification.
The Council created Sewer Benefit Area N with a sewer capacity fee for new development in the Village and Barrio area.
Ordinances CS-506 and CS-507 were adopted, rewriting section 21.10.030 for the 2024 state bills: no story limit on a detached ADU, no roof deck on any ADU, the Government Code's unit counts taken as written. Introduced 5 to 0 on January 27; in force outside the Coastal Zone 30 days later and inside it on the Commission's certification, still pending in October 2026.
The 2025 Building, Fire and Wildland-Urban Interface codes took effect, adopted on December 2, 2025; the water district's second rate step applied the same day.
The Planning Commission recommended the ADU amendment, after a six-week review of the draft from October 24 to December 5, 2025 that drew no comment.
Ordinance CS-495 adopted the State Fire Marshal's fire hazard severity zone map of March 24, 2025 into the Municipal Code.
The permit-ready plans went offline for the 2025 code cycle; the program page has said since that the updated plans are expected by summer 2026.
The Council adopted the Climate Action Plan update without the energy reach code measures, so the 2019 building ordinances stayed in force.
Ordinance CS-474, the 2024 zone code cleanup, touched the ADU section; the 2023 amendment for the state's height and parking changes was still at the Coastal Commission for the whole of 2024.
How BHI approaches a Carlsbad project
What we look at first on a Carlsbad lot.
On a Carlsbad lot the first question is whether it sits inside the Coastal Zone, because the February 2026 ordinance applies outside it now and inside it only once the Coastal Commission certifies it. Next come the bulletin's lines the code has moved past, such as the one-story limit, and the City's fees. Book a call and we go through your lot against both sets of rules.
What an ADU might rent for in Carlsbad
No agency publishes rents for ADUs on their own, so these are HUD's FY2027 Small Area Fair Market Rents for Carlsbad's four ZIP codes, the figures the ROI calculator runs on: the 40th percentile of what recent movers pay for a rental of each size, with utilities.
| ZIP | Studio | 1 bed | 2 bed | 3 bed |
|---|---|---|---|---|
| 92008 | $2,520 | $2,690 | $3,250 | $4,310 |
| 92009 | $2,850 | $3,040 | $3,670 | $4,870 |
| 92010 | $2,830 | $3,020 | $3,650 | $4,840 |
| 92011 | $3,140 | $3,350 | $4,050 | $5,370 |
HUD's FY2027 figures by ZIP code and bedroom count, exactly as the ROI calculator holds them; a ZIP whose land crosses the city line sits here because most of its people live in Carlsbad. Put your own lot into the ROI calculator for a 30-year projection.
Questions homeowners in Carlsbad ask
The eight questions people put to search and answer engines about building in Carlsbad, answered from the City's own code, bulletin and forms: five on ADUs, two on remodels and additions, one on a custom home.
Where's the cost line for a Carlsbad ADU: its size, the solar panels or the coastal permit?
Size is the first line. In Carlsbad an ADU of 750 square feet or less pays no impact fees, and a larger one pays them in proportion to your house's size, from 2027 counting only the space past 750 when the lot holds one or two ADUs. A new detached ADU must have solar panels. If the lot is in the Coastal Zone, a detached ADU also needs a minor coastal development permit, decided by the City Planner without a hearing.
My Carlsbad HOA doesn't want ADUs. Can it stop me?
No, an HOA can't forbid one. Carlsbad allows one attached or detached ADU on a single-family lot, plus a junior ADU inside the house, with no minimum lot size. The lot needs a house, or one planned along with the ADU. The City must approve a conversion of existing space paired with a new detached ADU of up to 800 square feet. Near the coast, the ADU still has to respect bluff setbacks and habitat buffers.
Can I build a two-story detached ADU in Carlsbad, or does it have to stay one story?
Since the City Council rewrote the ADU section on February 3, 2026 there is no story limit, only a height: 16 feet for a detached ADU, or 18 within half a mile's walk of Carlsbad Village or Poinsettia Station, and the zone's height above a detached garage. Detached units go up to 1,200 square feet, an attached one to half your house's floor area up to 1,200 and never under 800, a junior ADU to 500. Side and rear setbacks are four feet. The City's August 2026 bulletin still prints the old one-story line.
In Carlsbad, which comes first for an ADU, the coastal permit or the building permit?
The coastal permit, or both together. Carlsbad's Building Division issues the building permit, and in the Coastal Zone its Planning Division handles the coastal permit. The coastal permit has to be approved before or alongside the building permit. That review is ministerial, so there is no discretionary hearing to wait for.
Living west of the rail line in Carlsbad, what extra rules hit a detached ADU?
Parking is the one that's specific. West of the rail line, and in a coastal strip between it and I-5, any parking you lose to an ADU has to be replaced. A detached ADU in the Coastal Zone also needs a minor coastal development permit, which the City Planner decides without a hearing after notifying neighbors. Attached and junior ADUs are mostly exempt. No detached ADU can have a roof deck. The City's free permit-ready plans are offline while they're updated to the 2025 codes.
Does a Carlsbad kitchen refresh count as exempt work, or do I need a permit?
It's exempt only if the layout stays the same. Swapping cabinets and countertops, tiling, flooring and painting are fine without a permit when no plumbing or wiring changes. Moving a sink, adding a circuit, replacing concealed drain or supply pipe, or removing a wall needs a building permit from the City's Building Division. Exempt work still has to meet the building code.
Will a flat roof hold my Carlsbad second story to 24 feet?
Yes. In Carlsbad's R-1 zone a two-story house can reach 30 feet with a roof pitch of 3:12 or steeper, but only 24 feet with a flatter roof. Buildings can cover 40 percent of the lot. Most Coastal Zone additions skip the coastal permit. The exceptions are additions between the sea and the first public road that grow floor area 10 percent or more, and any within 50 feet of a bluff edge.
Before I design a custom home in Carlsbad, do the hillside standards or the 2025 fire maps apply?
Check both, after the zoning. Carlsbad's R-1 zone sets a 20-foot front yard, a 30-foot, two-story limit and 40 percent lot coverage. A new home in the Coastal Zone usually needs a coastal development permit. Hillside design standards apply on slopes of 15 percent or more with over 15 feet of rise. The 2025 fire maps matter too: in high or very high zones, a new home needs ignition-resistant construction.
Next steps
Check your lot against Carlsbad's rules and the Coastal Zone map, price the ADU, then read what fits your project.