Richardson does not allow accessory dwelling units. The Comprehensive Zoning Ordinance of 1956 lists no ADU, garage apartment or guest house as a use in any residential district, and Article II, Sec. 3 makes those lists closed — "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 recognises is Servants' quarters, and the definition rules out everything a homeowner would want it for: it must house full-time domestic help employed by the occupant, it is "not rented or otherwise used as a separate dwelling," and it "shall not have kitchen facilities or separate utility connections" (Art. I, Sec. 2). What Richardson does allow inside the main house is renting rooms — a maximum of two individual renters or tenants in a single-family dwelling. There is no ADU legalisation ordinance pending that could be found in a city source as of September 1, 2026.
Zoning & Size Requirements [1][2][3][4]
No — Richardson does not allow ADUs under current zoning. Richardson's Comprehensive Zoning Ordinance of 1956 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).
| Allowed Zones | None. No residential district in Richardson's Comprehensive Zoning Ordinance of 1956 lists an accessory dwelling unit, garage apartment or guest house among its permitted uses, and the lists are closed by Art. II, Sec. 3. In R-1500-M and R-1100-M — and in the same form across the R-2000-M through R-850-F districts — the permitted uses are single-family detached dwellings, accessory buildings (detached garage, carport, other accessory buildings), church, construction field office, farming, gardening, home-based business (no-impact), home occupation, public building, "rental rooms in a single-family dwelling, maximum of two individual renters or tenants," servants' quarters, parochial school on a church lot, antennas and rainwater harvesting (Art. IV, Sec. 1; Art. VII, Sec. 1) |
| Max Size (Detached) | N/A — a detached second dwelling is not a permitted use. A detached accessory building is 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 residence (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. An addition is simply part of the principal dwelling and is bound by the district's 30%-40% total building lot coverage |
| Max Size (JADU) | Not a category in Texas — Richardson's ordinance has no junior ADU designation |
| Max Height | N/A for ADUs. Accessory buildings are limited to one story: 12 feet for a building of 150 sq ft or less, 25 feet for anything larger (Art. IV, Sec. 3(b); Art. VII, Sec. 3(b)) |
| Max Units | 1 dwelling unit per lot. Richardson's residential districts permit "single-family detached dwellings" and nothing that would add a second unit; a duplex requires D-1400-M, D-2400-M or D-3000-M zoning, and anything else requires a PD planned development district with its own enumerated uses (Art. II, Sec. 1 and Sec. 3) |
Setback Requirements [1][2][3][4]
Richardson requires a rear setback of about 25 ft for a detached ADU, and parking requirements vary by unit size or location. Owner-occupancy is set by local rules (confirm with the city).
| Rear Setback | N/A for ADUs. For an accessory building, the district rear setback is 25 feet, but a detached garage, carport or other accessory building may extend into the rear setback with a minimum 3 feet from the rear lot line, or 18 inches where the rear lot line adjoins an alley (Art. IV, Sec. 4(g)(2); Art. VII, Sec. 4(g)(2)) |
| Side Setback | N/A for ADUs. An accessory building must meet the principal building's side setback — 7 feet on a lot under 80 feet wide, 10 feet at 80 to under 120 feet, 15 feet at 120 feet or more, and 20 feet on a corner lot adjacent to a side street — except that within the required rear setback a 3-foot side setback is allowed (Art. IV, Sec. 4(f); Art. VII, Sec. 4(f)). Note that the city's Building Inspection accessory-building page states 5 feet from the side property line for a building entirely within the designated rear yard, reducible to 3 feet with a UL-rated 1-hour firewall on both sides — check which figure your plan reviewer will apply with Building Inspection at 972-744-4180 |
| Front Setback | N/A for ADUs. The district front setback is 30 feet, and no accessory structure may sit forward of it (Art. IV, Sec. 4(e); Art. VII, Sec. 4(e)) |
| Parking Required | 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)). Enclosing or converting a garage triggers a requirement to replace it with a detached garage built of brick, stone or cementitious materials architecturally compatible with the house (Art. IV, Sec. 2(b)(2)) |
| Owner Occupancy | Moot 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 of the premises, 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)) |
| Min Lot Size | N/A for ADUs. District minimums for the lot itself are 9,000 sq ft in R-1500-M and 8,000 sq ft in R-1100-M, with minimum lot widths of 72 and 64 feet (Art. IV, Sec. 4(a)-(b); Art. VII, Sec. 4(a)-(b)) |
Permit Process & Fees [5][6]
An ADU permit in Richardson goes through a standard permit review. Confirm with Richardson Building Inspection (972-744-4180) — no published review timeline was found in a city source, and no ADU timeline exists. Permit fees: Confirm with Richardson Building Inspection (972-744-4180) — the accessory building permit fee schedule is not published on the accessory building page.
| Approval Process | There is no ADU permit in Richardson, because there is no ADU use to permit. A homeowner wanting a second unit would need a zoning change — most realistically a PD planned development district, where the permitted uses and the height and area regulations are written for the individual tract (Art. II, Sec. 1). That is a City Plan Commission and City Council process, not a counter application. For an ordinary accessory building, a building permit is required for any structure over 40 sq ft; structures of 150 sq ft or less need an application with a sketch, and anything larger needs scaled drawings (City of Richardson Building Inspection, Accessory Building) |
| Review Timeline | Confirm with Richardson Building Inspection (972-744-4180) — no published review timeline was found in a city source, and no ADU timeline exists |
| Permit Fees | Confirm with Richardson Building Inspection (972-744-4180) — the accessory building permit fee schedule is not published on the accessory building page |
| Impact Fees | Confirm with Richardson Development Services — no ADU-specific impact fee schedule was found in a city source |
| Plan Check | Scaled drawings are required for any accessory building over 150 sq ft, and each exterior wall of an accessory building over 150 sq ft must be at least 35 percent masonry (Art. IV, Sec. 2(b)(2)). Richardson has adopted the 2021 International Codes and the 2020 National Electrical Code. All contractors must be registered with the city before work starts |
| Pre-Approved Plans | None — no city pre-approved plan library exists, and none would be usable while ADUs are not a permitted use |
Get Free ADU Quotes in Richardson
Tell us about your project and we'll connect you with ADU builders serving Richardson. Free, no obligation — you choose who to work with.
Takes about a minute.
Up to 5 independent local ADU builders — never more, and we tell them nothing you don't submit here.
Compare quotes, verify license & insurance, hire (or don't). No spam either way.
🔒 Your info is secure. We share it only with contractors quoting your project. No spam, no obligation.
Just browsing? Search ADU builders near you by ZIP code.
Construction Costs [7]
Building an ADU in Richardson typically costs $120,000-$240,000 ($140-$265 per sq ft); a garage conversion runs $55,000-$140,000.
See what this means for your lot — get 5 free quotes from Richardson ADU builders →
| Average Build Cost | $120,000-$240,000 |
| Cost per Sq Ft | $140-$265 |
| Garage Conversion | $55,000-$140,000 |
| Prefab ADU (Installed) | $85,000-$190,000 |
Finance Your ADU Project
Most ADU projects are funded through HELOCs, construction loans, or cash-out refinancing. Compare rates from top lenders.
Some links on this page are affiliate links. We may earn a commission at no extra cost to you. Learn more
Rental Income Potential [8][9][10]
A 2-bedroom ADU in Richardson rents for around $1,500-$1,950/mo, an estimated 5-8% annual return (hypothetical — ADUs are not a permitted use in Richardson).
| Avg Rent (1 Bedroom) | $1,150-$1,500/mo |
| Avg Rent (2 Bedroom) | $1,500-$1,950/mo |
| Short-Term Rental | Moot for an ADU, since none may lawfully exist — but Richardson does regulate short-term rentals of the house itself. Registration is required for any residential property rented wholly or partly for under 30 consecutive days, including a room within the house. Ordinance 4597, passed August 10, 2026, added a 500-foot separation requirement between single-family short-term rentals and raised the annual registration fee from $100 to $300; a property within 500 feet of a registered STR is ineligible. Hotel Occupancy Tax is remitted directly to the city through the registration system from October 1, 2026. Renting for 30 days or more instead requires long-term single-family rental registration |
| Est. Annual ROI | 5-8% annual return (hypothetical — ADUs are not a permitted use in Richardson) |
Explore Prefab ADU Options
Prefab ADUs can save 20-40% vs. traditional construction and cut build time in half.
Some links on this page are affiliate links. We may earn a commission at no extra cost to you. Learn more
Recent Law Changes
What's Changed Recently
- Texas has no statewide ADU law — SB 673 (89th Legislature, Regular Session) would have preempted local ADU restrictions but died without final passage in 2025, so nothing overrides Richardson's own ordinance
- Ordinance No. 4590, adopted June 15, 2026, amended the use regulations of every residential district to add "Home-based business (no-impact)" and revised the Home occupation definition, in response to the 2025 state legislation now at Texas Local Government Code §229.902 — it did not touch accessory dwellings
- Ordinance No. 4597, passed August 10, 2026, imposed a 500-foot separation between single-family short-term rentals and raised the annual STR registration fee from $100 to $300; the city had earlier established an interim prohibition on new STR registrations
- Richardson's zoning is still the Comprehensive Zoning Ordinance of 1956 as amended; the residential use lists and the Servants' quarters definition remain the operative text as of September 1, 2026
- No ADU legalisation ordinance, moratorium or study could be found in a City of Richardson source as of September 1, 2026 — confirm current status with Richardson Development Services before assuming anything has changed
Tips for Building an ADU in Richardson
- Do not let a builder sell you a 'guest house' 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
- The 8%-of-lot-area cap on all detached structures is the number that stops most backyard projects before the use question even arises: on a 9,000 sq ft R-1500-M lot that is 720 sq ft total, garage included
- 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 get rental income out of 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 is architecturally compatible with the house — budget for that before pricing the conversion
- The only realistic path to a second unit is a PD planned development rezoning of your tract, which goes to the City Plan Commission and City Council. Talk to Development Services before you spend money on drawings
- If short-term letting is the plan, check the city's spacing map first — since August 10, 2026 a new single-family STR within 500 feet of an existing registered one is simply ineligible
- Building Inspection publishes its own accessory-building setback sheet whose side-yard numbers read differently from the zoning ordinance's. Get your specific setbacks confirmed in writing at 972-744-4180 before you pour a slab
ADU Builders in Richardson
Looking for an ADU builder in Richardson? ADU projects need a contractor experienced with local zoning, the permit process, and utility connections — not every general contractor has built one. We match Richardson homeowners with experienced local ADU contractors who provide free, no-obligation quotes. Getting at least three bids typically saves 20-40% on the same scope.
Sources & References
All data on this page is sourced from official government records and verified market data. View our full methodology.
- Richardson Comprehensive Zoning Ordinance of 1956, Art. I, Sec. 2 — Definitions (Accessory building; Servant's quarters) Municipal Code — Accessed 2026-09-01
- Richardson Comprehensive Zoning Ordinance of 1956, Art. II — Zoning Restrictions Generally (districts; closed use lists) Municipal Code — Accessed 2026-09-01
- Richardson Comprehensive Zoning Ordinance of 1956, Art. IV — R-1500-M Residential District Regulations (Ord. No. 4590, 6-15-26) Municipal Code — Accessed 2026-09-01
- Richardson Comprehensive Zoning Ordinance of 1956, Art. VII — R-1100-M Residential District Regulations (Ord. No. 4590, 6-15-26) Municipal Code — Accessed 2026-09-01
- Accessory Building — City of Richardson Building Inspection (972-744-4180) Planning Department — Accessed 2026-09-01
- Comprehensive Zoning Ordinance — City of Richardson Development Services Planning Department — Accessed 2026-09-01
- Angi — ADU Construction Cost Data Market Data — Accessed 2026-09-01
- Short-Term Rental Properties — City of Richardson Community Services (Ordinance 4597) Planning Department — Accessed 2026-09-01
- Zillow Rental Manager — Market Rent Data Market Data — Accessed 2026-09-01
- HUD Fair Market Rents Government Data — Accessed 2026-09-01
- Texas Legislature Online — SB 673, 89th Legislature Regular Session (bill history) Government Data — Accessed 2026-09-01
- U.S. Census Bureau QuickFacts — Richardson city, Texas Government Data — Accessed 2026-09-01
Frequently Asked Questions
Can I build an ADU in Richardson?
How much does an ADU cost in Richardson?
How much can I rent an ADU for in Richardson?
Do I need parking for an ADU in Richardson?
How long does it take to get an ADU permit in Richardson?
Ready to Build in Richardson?
Get free, no-obligation quotes from top-rated ADU contractors in Richardson.
Get Free Quotes →Build ADUs in Richardson?
Homeowners read this page while planning, then ask us to connect them with a local builder. We pass those requests to builders who cover Richardson — a flat fee only on the leads you accept, no subscription, and you contract directly with the homeowner.
See who's waiting in Texas →