Accessory Dwelling Unit (ADU) Construction in Hillsboro, OR — Costs $68,400 to $399,000
What does accessory dwelling unit (adu) construction cost in Hillsboro? Average $171,000, ranging $68,400–$399,000. Labor runs $35.4/hr locally — 14% above the national average. Free breakdown with material + labor split.
Hillsboro, OR Market
+14% vs nationalLabor Rate
$35.4/hr
Material Index
110
Avg Permit Cost
$1,408
Median Home Price
$443,953
Hillsboro is a mid-sized city in Oregon with a healthy pool of local contractors. Homeowners generally have several options to compare for a accessory dwelling unit (adu) construction, which helps keep pricing competitive. Costs in Hillsboro run slightly above the national average, though the gap is modest enough that smart material choices and timing can close it. The median home in Hillsboro is valued at $443,953, putting this project at about 38.5% of home value — a moderate investment with a projected 80% ROI.
Low Estimate
$68,400
National: $60,000
Mid-Range
$171,000
National: $150,000
High End
$399,000
National: $350,000
Per Sq Ft
$285
National: $250
Accessory Dwelling Unit (ADU) Construction Cost Calculator for Hillsboro
Adjusted for Hillsboro's labor rate ($35.4/hr) and material costs (index 110).
Mid-grade materials, good quality fixtures, standard options.
Estimated Total in Hillsboro
$171,000
Based on 200 sq ft at mid quality, adjusted for Hillsboro market rates.
Local Cost Breakdown
At Hillsboro's average rate of $35.4/hr (18% above national avg)
Material cost index 110 (10% above national baseline of 100)
Accessory Dwelling Unit (ADU) Construction vs. Home Value in Hillsboro
| Metric | Hillsboro | National Avg |
|---|---|---|
| Accessory Dwelling Unit (ADU) Construction (Mid-Range) | $171,000 | $150,000 |
| Median Home Price | $443,953 | $350,000 |
| Project as % of Home Value | 38.5% | 42.9% |
| Estimated ROI | 80% | 80% |
| Median Household Income | $69,054 | $75,000 |
What Affects the Price in Hillsboro
- 1Local labor rates ($35.4/hr in Hillsboro)
- 2Material cost index (110 vs national 100)
- 3Attached vs detached
- 4Size and bedroom count
- 5Kitchen and bath quality
- 6Local ADU regulations
Popular Upgrades
- Full kitchen
- Separate entrance
- Solar panels for energy independence
Other Projects in Hillsboro, OR
Second Story Addition
$228,000
Room Addition
$102,600
Swimming Pool Installation
$73,580
Garage Addition
$62,700
Home Addition
$90,880
Inground Swimming Pool
$73,320
Attic Conversion
$62,920
Swimming Pool Construction
$57,200
Accessory Dwelling Unit (ADU) Construction in Other Oregon Cities
Planning a Accessory Dwelling Unit (ADU) Construction in Hillsboro
Building permits are typically required for a accessory dwelling unit (adu) construction in Hillsboro. The average permit fee in this area is $1,408, though costs vary based on project scope. Permit fees in this market are above average — factor them into your total budget. Plan for 6-18 months from start to finish.
A accessory dwelling unit (adu) construction is a complex project best left to licensed professionals. In Hillsboro, skilled contractors charge an average of $35.4/hr, and the specialized nature of this work means cutting corners on labor can lead to costly rework.
For the median Hillsboro household earning $69,054/year, this project at $171,000 represents a significant investment. Consider financing options or phasing the work to spread costs over time.
Accessory Dwelling Unit (ADU) Construction — National Guide
See the full national cost guide with DIY tips, cost factors, and ROI analysis.
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