Confirm Parking Requirements
ADU parking requirements have changed dramatically. Many states and cities have eliminated or reduced parking mandates for ADUs, especially near public transit. This can be the difference between building an ADU or not.
Quick Summary
Traditional requirement
1-2 spaces
Near transit
Often waived
Garage conversion
No replacement needed*
*In most ADU-friendly states
Why Parking Rules Changed
Parking requirements were one of the biggest barriers to ADU construction. A required parking space can cost $5,000-$30,000 and consume valuable yard space. State legislatures recognized this and many have limited local parking mandates:
California
No parking required for ADUs within 1/2 mile of transit, in historic districts, in existing structures, or when there's a car share nearby. Garage conversions don't require replacement parking.
Oregon
Many cities have eliminated ADU parking requirements entirely. Portland requires no parking for ADUs and doesn't require replacing garage parking if converted.
Washington
Recent laws limit local parking requirements. Seattle requires no parking for ADUs. Many suburban cities have followed suit or reduced requirements.
Common Parking Scenarios
No Parking Required
Your ADU may not require any additional parking if:
- • You're within 1/2 mile of public transit
- • You're in a historic district
- • You're converting existing space (garage, basement)
- • Your city has eliminated ADU parking requirements
- • There's a car share service within certain distance
One Space Required
Many jurisdictions that still require parking limit it to one space. Options include:
- • Driveway parking (tandem behind existing car)
- • Carport or covered parking
- • New garage space
- • Street parking (if permitted by your code)
Garage Conversion
Converting your garage to an ADU used to require replacing the parking. Now:
- • Most ADU-friendly states: No replacement required
- • Some cities: Replacement required but can be uncovered
- • Traditional: Must replace garage spaces elsewhere
Tandem Parking
Tandem parking (cars lined up behind each other in driveway) is often acceptable for ADU parking. Check if your jurisdiction accepts this—many do, though some require side-by-side spaces.
Calculating Transit Distance
If parking exemptions depend on transit proximity, know how to calculate:
Find your nearest bus stop, rail station, or transit hub
Measure walking distance (not straight-line) from your property
Common thresholds: 1/4 mile, 1/2 mile, or 3/4 mile
Frequency requirements may apply (e.g., 15-minute service)
Tip: Use Google Maps "walking directions" to measure the distance. 1/2 mile is approximately a 10-minute walk.
True Cost of a Parking Space
If you do need to provide parking, understand the real costs:
| Parking Type | Cost | Space Used |
|---|---|---|
| Driveway extension | $3,000-$8,000 | 180-200 sq ft |
| Carport | $5,000-$15,000 | 200-250 sq ft |
| New garage | $25,000-$50,000 | 250-400 sq ft |
| Lost yard space value | Varies by market | - |
Frequently Asked Questions
What if my HOA requires parking?
HOAs may have their own parking rules separate from city requirements. In some states (like California), state law limits HOA ability to require more parking than the city, but this is evolving. Check both your CC&Rs and state law.
Can I charge ADU tenants for parking separately?
Yes. Many landlords include parking with rent, but you can also charge separately or not provide parking at all (if not required). Unbundling parking can help target tenants who don't own cars.
Does street parking count?
Usually no—most codes require on-site parking. However, if your code doesn't require ADU parking at all, street parking becomes a practical (though not code-required) option for your tenants.
Feasibility Complete!
You've completed the feasibility phase. Next, you'll decide what type of ADU to build—detached, attached, garage conversion, or prefab.