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ADU Rules in Richardson, Texas

Complete guide to building an Accessory Dwelling Unit in Richardson — zoning, setbacks, permits, costs, and more.

Max Size: N/A: a detached second dwelling is not a permitted use. Detached accessory buildings are capped instead: all detached structures together, garages included, may occupy no more than 8% of the lot area and may not exceed 40% of the floor area of the principal dwelling (Art. IV, Sec. 4(d)(2); Art. VII, Sec. 4(d)(2)). Servants' quarters, the only accessory living space allowed, may not have kitchen facilities or separate utility connections (Art. I, Sec. 2) Setbacks: N/A for ADUs. The district rear setback is 25 ft, but a detached garage, carport or other accessory building may extend into it with a minimum 3 ft from the rear lot line, or 18 in where the rear lot line adjoins an alley (Art. IV, Sec. 4(g)(2); Art. VII, Sec. 4(g)(2)). Building Inspection measures these to the roof overhang Parking: Varies Verified: 2026-09-20

Researched by ADU Zoning Hub · verified 2026-09-20 against Richardson planning code and Texas ADU law · methodology · 22 sources cited ↓

ADU Score: 2/10
Restrictive · how we score

Are ADUs allowed in Richardson, TX? [1][2][3][4][5][6]

No. Richardson does not allow accessory dwelling units under current zoning. Richardson's Comprehensive Zoning Ordinance of 1956, codified through Ord. No. 4590 (June 15, 2026) with nothing in the ten ordinances adopted since, lists no accessory dwelling unit, garage apartment or guest house as a permitted use in any residential district, and Art. II, Sec. 3 closes the use lists. The one accessory living space it recognises, Servants' quarters, is by definition not rented, not a separate dwelling, and may not have kitchen facilities or separate utility connections (Art. I, Sec. 2). Council began a zoning-ordinance modernisation in February 2026; no ADU text has been published. Narrow exceptions may exist for existing legal units, so confirm your specific parcel with the planning department before assuming a project is possible.

Maximum sizeN/A: a detached second dwelling is not a permitted use. Detached accessory buildings are capped instead: all detached structures together, garages included, may occupy no more than 8% of the lot area and may not exceed 40% of the floor area of the principal dwelling (Art. IV, Sec. 4(d)(2); Art. VII, Sec. 4(d)(2)). Servants' quarters, the only accessory living space allowed, may not have kitchen facilities or separate utility connections (Art. I, Sec. 2)
SetbacksRear N/A for ADUs. The district rear setback is 25 ft, but a detached garage, carport or other accessory building may extend into it with a minimum 3 ft from the rear lot line, or 18 in where the rear lot line adjoins an alley (Art. IV, Sec. 4(g)(2); Art. VII, Sec. 4(g)(2)). Building Inspection measures these to the roof overhang · Side N/A for ADUs. An accessory building must meet the principal building's side setback: 7 ft on a lot under 80 ft wide, 10 ft at 80 to under 120 ft, 15 ft at 120 ft or more, 20 ft on a corner lot beside a side street; within the required rear setback 3 ft is allowed (Art. IV, Sec. 4(f)(1), (f)(3)). Building Inspection's accessory-building sheet applies 5 ft for a building entirely within the rear 25 ft, or 3 ft with a UL-rated 1-hour fire wall both sides; confirm at 972-744-4180
ParkingN/A for ADUs: no ADU standard exists. The residential baseline is two off-street spaces in an enclosed garage behind the front building line for each dwelling unit, attached or detached (Art. IV, Sec. 4(h)(1); Art. VII, Sec. 4(h)(1)). Converting a garage to living space requires a replacement detached garage of brick, stone or cementitious materials compatible with the house (Art. IV, Sec. 2(b)(2)), and any front-yard driveway must be removed or reconfigured (Sec. 4(h)(4))
Owner-occupancyMoot for ADUs, since none may be built. Servants' quarters must be occupied by persons employed full-time on the premises as domestic help by the occupant, and may not be rented (Art. I, Sec. 2). Renting rooms inside the house is allowed to a maximum of two individual renters or tenants (Art. IV, Sec. 1(j); Art. VII, Sec. 1(j))

Do I need a permit to build an ADU in Richardson? [7][8][9]

Yes. Every ADU in Richardson needs a building permit. Review process: There is no ADU permit in Richardson because there is no ADU use to permit. A second unit would need a zoning change, realistically a PD planned development district whose uses and standards are written for the individual tract (Art. II, Sec. 1; Art. XXI-C): a City Plan Commission and City Council process, filing fee $2,500 (Appendix B), not a counter application. For an ordinary accessory building, Building Inspection requires a permit for any structure over 40 sq ft; 150 sq ft or less needs an application with a location sketch, anything larger needs scaled drawings. Submit by email to permits@cor.gov or at 2360 Campbell Creek Blvd, Suite 550.

Permit feesAccessory building permit: $100 for a structure of 150 sq ft or less, $200 for one larger than 150 sq ft; a room addition is $200 up to 500 sq ft, then $200 plus $0.10/sq ft (Appendix B, Master Fee Schedule, Ord. 4559, Sept. 15, 2025).
Typical timelineNot published. Building Inspection (972-744-4180) posts no review time for accessory-building permits, and no ADU timeline exists because no ADU use exists.
Official Richardson links:

Three things to know before you build in Richardson

  • Do not let a builder sell you a 'guest house' or 'casita' in Richardson: the code has no such use, and Servants' quarters, the only accessory living space, cannot legally have a kitchen or its own utility connections (Art. I, Sec. 2)
  • The 8%-of-lot-area cap on all detached structures stops most backyard projects before the use question arises: on a 9,000 sq ft R-1500-M lot that is 720 sq ft in total, garage included, and never more than 40% of the house's floor area
  • You can still rent rooms. Art. IV, Sec. 1(j) allows renting to a maximum of two individual renters or tenants inside the single-family dwelling, the legal way to earn rental income from a Richardson house without a second unit

Last verified 2026-09-20 against Richardson planning code — status: prohibited. How we verify

Richardson does not allow accessory dwelling units, and that has not changed as of September 20, 2026. The Comprehensive Zoning Ordinance of 1956 (codified through Ord. No. 4590 of June 15, 2026; ten later ordinances, Nos. 4591-4600, are all site-specific rezonings, STR and fee changes) lists no ADU, garage apartment or guest house in any residential district, and Art. II, Sec. 3 closes the use lists: "no building shall be erected for or converted to any use other than provided in the regulations prescribed for the district." The only accessory living space the code names is Servants' quarters, defined in Art. I, Sec. 2 as housing for full-time domestic help employed by the occupant, "not rented or otherwise used as a separate dwelling," with no kitchen facilities or separate utility connections. What a homeowner can do is rent rooms inside the house to a maximum of two individual renters or tenants (Art. IV, Sec. 1(j)), or build a plain accessory building: $100 or $200 permit, 8%-of-lot cap, 25 ft height. City Council told staff on February 2, 2026 to start modernising the 1956 ordinance around "missing middle" housing, but no draft text and no ADU provision has been published.

Zoning & Size Requirements [1][2][3][4][5][6]

No — Richardson does not allow ADUs under current zoning. Richardson's Comprehensive Zoning Ordinance of 1956, codified through Ord. No. 4590 (June 15, 2026) with nothing in the ten ordinances adopted since, lists no accessory dwelling unit, garage apartment or guest house as a permitted use in any residential district, and Art. II, Sec. 3 closes the use lists. The one accessory living space it recognises, Servants' quarters, is by definition not rented, not a separate dwelling, and may not have kitchen facilities or separate utility connections (Art. I, Sec. 2). Council began a zoning-ordinance modernisation in February 2026; no ADU text has been published.

Allowed ZonesNone. No residential district lists an accessory dwelling unit, garage apartment or guest house, and Art. II, Sec. 3 closes every use list. In R-1500-M (Art. IV, Sec. 1) and R-1100-M (Art. VII, Sec. 1) the uses are single-family detached dwellings; accessory buildings (detached garage, carport, other); church; construction field office; farming; gardening; home-based business; home occupation; public building; rental rooms (max two renters); servants' quarters; parochial school; antennas
Max Size (Detached)N/A: a detached second dwelling is not a permitted use. Detached accessory buildings are capped instead: all detached structures together, garages included, may occupy no more than 8% of the lot area and may not exceed 40% of the floor area of the principal dwelling (Art. IV, Sec. 4(d)(2); Art. VII, Sec. 4(d)(2)). Servants' quarters, the only accessory living space allowed, may not have kitchen facilities or separate utility connections (Art. I, Sec. 2)
Max Size (Attached)N/A: no attached ADU category exists. An addition is part of the principal dwelling and counts toward total lot coverage: 40% of the lot in R-1500-M (Art. IV, Sec. 4(d)(1)); 30% in R-1100-M, or 35% in subdivisions platted before March 31, 1975 (Art. VII, Sec. 4(d)(1))
Max Size (JADU)Not a category in Texas, and Richardson's ordinance has no junior ADU designation
Max HeightN/A for ADUs. Accessory buildings are limited to one story: 12 ft for a building of 150 sq ft or less, 25 ft for anything larger (Art. IV, Sec. 3(b); Art. VII, Sec. 3(b)). The principal house may be two stories, first story 25 ft and second 15 ft (Sec. 3(a))
Max Units1 dwelling unit per lot. The residential districts permit "single-family detached dwellings" (a structure containing one dwelling unit, Art. I, Sec. 2) and nothing that adds a second unit; a duplex needs D-1400-M, D-2400-M or D-3000-M zoning, and anything else needs a PD planned development district with its own enumerated uses (Art. II, Sec. 1 and Sec. 3)

Setback Requirements [1][2][3][4][5][6]

Because Richardson does not permit ADUs, there are no ADU-specific setback or parking standards; the accessory-structure rules below are what a future unit would start from. Owner-occupancy is set by local rules (confirm with the city).

Rear SetbackN/A for ADUs. The district rear setback is 25 ft, but a detached garage, carport or other accessory building may extend into it with a minimum 3 ft from the rear lot line, or 18 in where the rear lot line adjoins an alley (Art. IV, Sec. 4(g)(2); Art. VII, Sec. 4(g)(2)). Building Inspection measures these to the roof overhang
Side SetbackN/A for ADUs. An accessory building must meet the principal building's side setback: 7 ft on a lot under 80 ft wide, 10 ft at 80 to under 120 ft, 15 ft at 120 ft or more, 20 ft on a corner lot beside a side street; within the required rear setback 3 ft is allowed (Art. IV, Sec. 4(f)(1), (f)(3)). Building Inspection's accessory-building sheet applies 5 ft for a building entirely within the rear 25 ft, or 3 ft with a UL-rated 1-hour fire wall both sides; confirm at 972-744-4180
Front SetbackN/A for ADUs. The district front setback is 30 ft (up to 50 ft where an established building line governs), and no accessory structure may sit forward of it; unenclosed porches and similar appendages may project 5 ft (Art. IV, Sec. 4(e); Art. VII, Sec. 4(e))
Parking RequiredN/A for ADUs: no ADU standard exists. The residential baseline is two off-street spaces in an enclosed garage behind the front building line for each dwelling unit, attached or detached (Art. IV, Sec. 4(h)(1); Art. VII, Sec. 4(h)(1)). Converting a garage to living space requires a replacement detached garage of brick, stone or cementitious materials compatible with the house (Art. IV, Sec. 2(b)(2)), and any front-yard driveway must be removed or reconfigured (Sec. 4(h)(4))
Owner OccupancyMoot for ADUs, since none may be built. Servants' quarters must be occupied by persons employed full-time on the premises as domestic help by the occupant, and may not be rented (Art. I, Sec. 2). Renting rooms inside the house is allowed to a maximum of two individual renters or tenants (Art. IV, Sec. 1(j); Art. VII, Sec. 1(j))
Min Lot SizeN/A for ADUs. District minimums for the lot itself: 9,000 sq ft, 72 ft wide and 125 ft deep in R-1500-M (Art. IV, Sec. 4(a)-(c)); 8,000 sq ft and 64 ft wide in R-1100-M (Art. VII, Sec. 4(a)-(b))

Permit Process & Fees [7][8][9]

Richardson cannot issue an ADU permit under current zoning. The fees and timelines below are the general building-permit terms that would apply if the rules change.

Approval ProcessThere is no ADU permit in Richardson because there is no ADU use to permit. A second unit would need a zoning change, realistically a PD planned development district whose uses and standards are written for the individual tract (Art. II, Sec. 1; Art. XXI-C): a City Plan Commission and City Council process, filing fee $2,500 (Appendix B), not a counter application. For an ordinary accessory building, Building Inspection requires a permit for any structure over 40 sq ft; 150 sq ft or less needs an application with a location sketch, anything larger needs scaled drawings. Submit by email to permits@cor.gov or at 2360 Campbell Creek Blvd, Suite 550
Review TimelineNot published. Building Inspection (972-744-4180) posts no review time for accessory-building permits, and no ADU timeline exists because no ADU use exists.
Permit FeesAccessory building permit: $100 for a structure of 150 sq ft or less, $200 for one larger than 150 sq ft; a room addition is $200 up to 500 sq ft, then $200 plus $0.10/sq ft (Appendix B, Master Fee Schedule, Ord. 4559, Sept. 15, 2025).
Impact FeesNone found. The Master Fee Schedule (Appendix B, as amended through Ord. 4560, Oct. 13, 2025) lists no development impact fee for residential work; the only impact-related charges are traffic impact analysis reviews filed with a zoning request ($500 without modelling, $1,500 with). Water and sewer connection charges are billed per the schedule; confirm with Development Services
Plan CheckScaled drawings are required for any accessory building over 150 sq ft, and each exterior wall of a building over 150 sq ft must be at least 35% masonry (Art. IV, Sec. 2(b)(2)); 150 sq ft or less may be wood or metal. The building must be permanently anchored, and the approved permit must be posted on site before work starts. Richardson has adopted the 2021 International Codes and the 2020 National Electrical Code, and every contractor must be registered with the city ($100, Sec. 6-116)
Pre-Approved PlansNone. No city pre-approved plan library exists, and none would be usable while ADUs are not a permitted use

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Construction Costs [10][11][12]

If ADUs become legal in Richardson, building one would run roughly $140,000-$350,000 ($250-$400 per sq ft) at today's regional rates; a garage conversion about $30,000-$100,000.

See what this means for your lot — ask Richardson ADU builders for a quote →

Average Build Cost$140,000-$350,000
Cost per Sq Ft$250-$400
Garage Conversion$30,000-$100,000
Prefab ADU (Installed)$150,000-$300,000

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Rental Income Potential [13][14][15][16]

A 2-bedroom unit in Richardson would rent for around $1,850-$2,300/mo at current market rates — a hypothetical figure while ADUs are not permitted.

Avg Rent (1 Bedroom)$1,450-$1,950/mo
Avg Rent (2 Bedroom)$1,850-$2,300/mo
Short-Term RentalMoot for an ADU, but the house is regulated: any rental under 30 days, even a room, needs registration (Ch. 6, Art. XIII). Ord. 4597 (Aug. 10, 2026): no new single-family STR within 500 ft of a registered one; $300/yr.
Est. Annual ROI5-8% annual return (hypothetical: ADUs are not a permitted use in Richardson)

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Recent Law Changes

What's Changed Recently

  • Code currency: Municode Supp. No. 35, Update 2 codifies the Comprehensive Zoning Ordinance through Ord. No. 4590 (June 15, 2026). The ten ordinances adopted since (Nos. 4591-4600, July 13 to August 17, 2026) are a charter renumbering, site-specific PD rezonings and special development plans, mobile-vendor and open-air-market rules, and the STR amendments; none adds an accessory dwelling use or amends a residential district's use list
  • City Council directed staff on February 2, 2026 to begin modernising the 1956 Comprehensive Zoning Ordinance, citing 69 individual zoning changes since 2023 and a goal of supporting "missing middle" housing and more by-right uses; a work plan and benchmarking were to follow. As of September 20, 2026 no draft ordinance and no ADU provision has been published
  • Texas has no statewide ADU law: SB 673 (89th Legislature, 2025), which would have preempted local ADU bans, was placed on the House General State Calendar on May 26, 2025 and died at sine die. SB 15 (small-lot subdivisions) and SB 840 (commercial-to-residential) took effect September 1, 2025 but apply only to cities over 150,000 population, which excludes Richardson
  • Ordinance No. 4590, adopted June 15, 2026, added "Home-based business (no-impact)" to every residential district's use list and revised the Home occupation definition (Texas Local Government Code Ch. 229) without touching accessory dwellings
  • Ordinances 4597 and 4598, passed August 10, 2026, added a 500-ft separation between single-family short-term rentals (Sec. 6-512(g)) and raised the annual STR registration fee from $100 to $300, amending the STR ordinance (No. 4577) of March 23, 2026
  • Envision Richardson, the comprehensive plan approved November 11, 2024, is the policy basis the zoning update is meant to implement; the plan does not itself change any zoning regulation

Tips for Building an ADU in Richardson

  • Do not let a builder sell you a 'guest house' or 'casita' in Richardson: the code has no such use, and Servants' quarters, the only accessory living space, cannot legally have a kitchen or its own utility connections (Art. I, Sec. 2)
  • The 8%-of-lot-area cap on all detached structures stops most backyard projects before the use question arises: on a 9,000 sq ft R-1500-M lot that is 720 sq ft in total, garage included, and never more than 40% of the house's floor area
  • You can still rent rooms. Art. IV, Sec. 1(j) allows renting to a maximum of two individual renters or tenants inside the single-family dwelling, the legal way to earn rental income from a Richardson house without a second unit
  • If you convert or enclose your garage, the code makes you replace it with a detached garage in brick, stone or cementitious material that matches the house (Art. IV, Sec. 2(b)(2)), and the new garage needs 24 ft of pavement in front of the door for manoeuvring; budget for that before pricing the conversion
  • The only realistic path to a second unit today is a PD planned development rezoning of your tract ($2,500 filing fee) through the City Plan Commission and City Council. Talk to Development Services before you spend money on drawings
  • Watch the zoning ordinance rewrite. Council opened the door in February 2026 to 'missing middle' housing and more by-right uses; if an accessory dwelling use is ever written in, it will appear as a text amendment to Art. I and the residential articles, not as a permit type
  • If short-term letting is the plan, check the city's spacing first: since August 10, 2026 a new single-family STR within 500 ft of an existing registered one is ineligible, and registration now costs $300 a year
  • Cost basis: the cost ranges are hypothetical for Richardson and come from dated 2026 DFW guides (UHS Remodeling casita guide, June 29, 2026: $150,000-$400,000+ ground-up, $250-$400 per finished sq ft; UHS garage-conversion guide, April 24, 2026: $25,000-$75,000, up to $100,000 with a kitchen; Dwelling Index modular guide, May 27, 2026: $200,000-$400,000+ installed). Rents: HUD FY2027 Small Area FMRs for ZIPs 75080-75082 ($1,720-$1,970 1BR, $2,020-$2,320 2BR) and the Zumper Richardson median of September 20, 2026 ($1,436 1BR, $1,828 2BR)

ADU Builders in Richardson

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Sources & References

All data on this page is sourced from official government records and verified market data. View our full methodology.

  1. Richardson Comprehensive Zoning Ordinance of 1956, Art. I, Sec. 2 — Definitions (Accessory building; Servant's quarters; Single-family detached dwelling); Supp. No. 35, Update 2, codified through Ord. No. 4590 (6-15-26) Municipal Code — Accessed 2026-09-20
  2. Richardson Comprehensive Zoning Ordinance of 1956, Art. II — Zoning Restrictions Generally, Secs. 1-3 (districts; closed use lists) Municipal Code — Accessed 2026-09-20
  3. Richardson Comprehensive Zoning Ordinance of 1956, Art. IV — R-1500-M Residential District Regulations, Secs. 1-4 (Ord. No. 4590, 6-15-26) Municipal Code — Accessed 2026-09-20
  4. Richardson Comprehensive Zoning Ordinance of 1956, Art. VII — R-1100-M Residential District Regulations, Secs. 1-4 (Ord. No. 4590, 6-15-26) Municipal Code — Accessed 2026-09-20
  5. Municode OrdBank — Richardson ordinances pending codification, Nos. 4591-4600 (July 13 to Aug. 17, 2026): titles and adoption dates ordinance — Accessed 2026-09-20
  6. Comprehensive Zoning Ordinance — City of Richardson Development Services (article index) Planning Department — Accessed 2026-09-20
  7. Accessory Building — City of Richardson Building Inspection (permit threshold, setback sheet, submittal, 972-744-4180) Planning Department — Accessed 2026-09-20
  8. Richardson Code of Ordinances, Appendix B — Master Fee Schedule: Building Inspection and Development Services fees (Ord. No. 4559, 9-15-25; Ord. No. 4560, 10-13-25) fee_schedule — Accessed 2026-09-20
  9. Residential Permit Types — City of Richardson Building Inspection Planning Department — Accessed 2026-09-20
  10. DFW ADU & Casita Cost Guide 2026 (June 29, 2026), UHS Remodeling industry — Accessed 2026-09-20
  11. Cost To Convert Garage Into Living Space In DFW Texas 2026 (April 24, 2026), UHS Remodeling industry — Accessed 2026-09-20
  12. Prefab Modular ADU: 2026 Costs, Code Paths & Lot Fit (updated May 27, 2026), Dwelling Index industry — Accessed 2026-09-20
  13. Ordinance No. 4597 (Aug. 10, 2026) — amending Ch. 6, Art. XIII short-term rentals: Sec. 6-512(g) 500-ft separation; Ordinance No. 4598 (Aug. 10, 2026) — STR registration fee $100 to $300 (Municode OrdBank) ordinance — Accessed 2026-09-20
  14. Richardson Code of Ordinances, Ch. 6, Art. XIII, Sec. 6-511 — Short-term rental definitions Municipal Code — Accessed 2026-09-20
  15. HUD FY2027 Small Area Fair Market Rents — Dallas, TX HMFA, ZIP codes 75080, 75081, 75082 Government Data — Accessed 2026-09-20
  16. Richardson, TX rent research (median, updated September 20, 2026), Zumper Market Data — Accessed 2026-09-20
  17. Texas Legislature Online — SB 673, 89th Legislature Regular Session (bill history: last action 5-26-2025, no final passage) Government Data — Accessed 2026-09-20
  18. Texas Legislature Online — SB 15, 89R, enrolled text, Local Government Code Sec. 211.052 applicability (cities over 150,000) state_statute — Accessed 2026-09-20
  19. Texas Legislature Online — SB 840, 89R, enrolled text, Local Government Code Sec. 218.002 applicability (cities over 150,000) state_statute — Accessed 2026-09-20
  20. Richardson set to update comprehensive zoning ordinance to allow for more development — Community Impact, February 6, 2026 (Feb. 2 council briefing) news_media — Accessed 2026-09-20
  21. Envision Richardson Comprehensive Plan — City of Richardson Development Services (approved November 11, 2024) Planning Department — Accessed 2026-09-20
  22. U.S. Census Bureau QuickFacts — Richardson city, Texas Government Data — Accessed 2026-09-01

Frequently Asked Questions

Can I build an ADU in Richardson?

No — Richardson does not allow ADUs under current zoning. Richardson's Comprehensive Zoning Ordinance of 1956, codified through Ord. No. 4590 (June 15, 2026) with nothing in the ten ordinances adopted since, lists no accessory dwelling unit, garage apartment or guest house as a permitted use in any residential district, and Art. II, Sec. 3 closes the use lists. The one accessory living space it recognises, Servants' quarters, is by definition not rented, not a separate dwelling, and may not have kitchen facilities or separate utility connections (Art. I, Sec. 2). Council began a zoning-ordinance modernisation in February 2026; no ADU text has been published. Details: None. No residential district lists an accessory dwelling unit, garage apartment or guest house, and Art. II, Sec. 3 closes every use list. In R-1500-M (Art. IV, Sec. 1) and R-1100-M (Art. VII, Sec. 1) the uses are single-family detached dwellings; accessory buildings (detached garage, carport, other); church; construction field office; farming; gardening; home-based business; home occupation; public building; rental rooms (max two renters); servants' quarters; parochial school; antennas.

How much does an ADU cost in Richardson?

ADU construction in Richardson typically costs $140,000-$350,000. Garage conversions run $30,000-$100,000, and prefab ADUs cost $150,000-$300,000.

How much can I rent an ADU for in Richardson?

Average ADU rents in Richardson are $1,450-$1,950/mo for a 1-bedroom and $1,850-$2,300/mo for a 2-bedroom unit.

Do I need parking for an ADU in Richardson?

N/A for ADUs: no ADU standard exists. The residential baseline is two off-street spaces in an enclosed garage behind the front building line for each dwelling unit, attached or detached (Art. IV, Sec. 4(h)(1); Art. VII, Sec. 4(h)(1)). Converting a garage to living space requires a replacement detached garage of brick, stone or cementitious materials compatible with the house (Art. IV, Sec. 2(b)(2)), and any front-yard driveway must be removed or reconfigured (Sec. 4(h)(4)). Check with Richardson planning department for the latest Texas ADU parking rules, as many states have relaxed requirements in recent years.

How long does it take to get an ADU permit in Richardson?

Richardson does not publish a standard ADU review timeline. Building Inspection (972-744-4180) posts no review time for accessory-building permits, and no ADU timeline exists because no ADU use exists. Permit fees: Accessory building permit: $100 for a structure of 150 sq ft or less, $200 for one larger than 150 sq ft; a room addition is $200 up to 500 sq ft, then $200 plus $0.10/sq ft (Appendix B, Master Fee Schedule, Ord. 4559, Sept. 15, 2025).

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Richardson ADU FAQ

Answers to every common question about building an ADU in Richardson — costs, rules, permits, rental income.

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Richardson ADU Costs

Detailed cost breakdown: construction $140,000-$350,000, garage conversion $30,000-$100,000, plus ROI analysis.

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Garage Conversion ADU Guide

Complete guide to costs ($80K-$180K), impact fee savings, and permits for garage-to-ADU conversions.

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ADU vs Mother-in-Law Suite

Legal differences that affect what you can build, how you can use it, and rental rights.

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About this information: This page is an informational summary of publicly available regulations - it is not legal, financial, or professional advice, and it is not a substitute for confirming requirements with your local planning department. Rules change frequently; always verify current requirements before designing, budgeting, or building. Last verified: 2026-09-20. Contractors we introduce are independent businesses - verify license and insurance directly before hiring. Spotted an error? Tell us - we verify against primary sources and correct quickly.

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