Complete 2026 cost breakdown: construction, permits, financing, and expected rental ROI.
Calculate your Pasadena ADU cost →Building an ADU in Pasadena costs between $150,000-$400,000 for new construction, with per-square-foot costs averaging $300-$450. These figures include design, permitting, site preparation, and construction. The most affordable option is a garage conversion at $120,000-$190,000, while prefab/modular ADUs fall in between at $180,000-$300,000.
| Cost Category | Estimated Range |
|---|---|
| Architectural Plans | $3,000 – $15,000 |
| Permits & Fees | Valuation-based (FY2027 General Fee Schedule, adopted June 8, 2026): building permit $1,738 plus $6 per $1,000 over $100,000; plan check $2,607 plus $9 per $1,000; Construction Tax 1.92%; General Plan and Technology fees 0.5% each; refundable C&D deposit flat $1,000; new address $345. |
| Impact Fees | Residential Impact Fee (PMC 4.17.050) is waived for ADUs of 900 sq ft or less and for any ADU with an executed Housing Agreement (effective July 17, 2025). A larger ADU pays a share of the per-unit fee (FY2027: $24,530 studio to $45,407 five-bedroom) prorated by ADU size against the main house. ADUs of 750 sq ft or less are also exempt under Gov. Code 66311.5. |
| Site Prep & Foundation | $10,000 – $35,000 |
| Framing & Structure | $15,000 – $45,000 |
| Plumbing | $8,000 – $20,000 |
| Electrical | $5,000 – $15,000 |
| HVAC | $3,000 – $8,000 |
| Interior Finishes | $15,000 – $40,000 |
Quotes for the same ADU commonly vary 20–40% between builders. We pass your request to up to 5 local builders serving Pasadena, where we have them — free, no obligation.
Get Pasadena builder quotes →Permit fees in Pasadena are Valuation-based (FY2027 General Fee Schedule, adopted June 8, 2026): building permit $1,738 plus $6 per $1,000 over $100,000; plan check $2,607 plus $9 per $1,000; Construction Tax 1.92%; General Plan and Technology fees 0.5% each; refundable C&D deposit flat $1,000; new address $345.. The review timeline is 60 days from a complete application for the city to act, or the ADU is deemed approved (Gov. Code 66317; SB 543 from Jan 2026). For Standard Plan submittals the city publishes about 3-4 weeks for first plan check and about 2 weeks per resubmittal., with plan check: Plan check is 50% off for ADUs using a city Standard Plan or with a Housing Agreement (affordability covenant or landlord agreement), and those units also skip the Construction Tax, General Plan Maintenance and Technology fees. ADUs of 900 sq ft or less without an agreement get 25% off those three items. Single-family sites only; reductions are not retroactive (effective May 6, 2025).. Impact fees are Residential Impact Fee (PMC 4.17.050) is waived for ADUs of 900 sq ft or less and for any ADU with an executed Housing Agreement (effective July 17, 2025). A larger ADU pays a share of the per-unit fee (FY2027: $24,530 studio to $45,407 five-bedroom) prorated by ADU size against the main house. ADUs of 750 sq ft or less are also exempt under Gov. Code 66311.5.. Pre-approved plans: Yes. As of August 2026 one free city Standard Plan compliant with the 2025 California Building Code is available citywide: Prototype A, a 374 sq ft studio. The five earlier plans (374-750 sq ft) expired Dec 31, 2025 and may only be used on properties red-tagged in the Eaton Fire. Plans cannot be modified, and a Hold Harmless Agreement is required..
| 1-Bedroom Rent | $2,300-$3,000/month |
| 2-Bedroom Rent | $3,100-$3,750/month |
| Annual Rental Income (est.) | $31,800/year |
| Payback Period (est.) | 8.6 years |
| Short-Term Rental | No. An ADU or JADU legally created on or after Jan 1, 2017 may only be rented for terms longer than 30 days, and neither may be sold separately from the main home except by a qualified nonprofit under Gov. |
| Overall ROI Estimate | 7-11% gross rental yield on a $400,000 detached build at $2,300-$3,750/mo, higher for a garage conversion (estimate before taxes, vacancy and financing) |
A typical ADU in Pasadena generates approximately $31,800 per year in rental income based on average 1-bedroom rents. At an average construction cost of $275,000, the estimated payback period is 8.6 years — before accounting for the resale value the ADU adds, which an appraiser determines from comparable sales in Pasadena and varies by market (often less than build cost).
1. Garage conversions save 40-60% vs new construction since the shell already exists. Average cost in Pasadena: $120,000-$190,000.
2. Prefab/modular ADUs offer predictable pricing and faster timelines. Average: $180,000-$300,000.
3. Pre-approved plans — available in Pasadena, which can save $3,000-$10,000 in design costs and 2-3 months in review time. See which cities offer pre-approved ADU plans.
4. State grants — California's CalHFA ADU grant (up to $40K) is currently paused; check calhfa.ca.gov/adu for status and your state for active programs.
5. Get multiple bids — ADU contractor pricing varies 20-40% for the same project. We recommend getting at least 3 quotes.
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