Frequently Asked Questions

• Up to two ADUs can be built per lot with a principal unit (e.g. single family home, duplex, townhome). ADUs can be attached (such as in a basement attic or garage conversion) or detached.
• ADUs can be up to 1,000 square feet of habitable area. See ECC 15.540.040 for full design standards for ADUs. See Building Bulletin-14 (BB-14) Design Criteria & Regulations for relevant code and design criteria references. 
• There is no parking requirement for the first ADU. One space is required for the second ADU. If your ADU reduces off-street parking for your principal unit, you may need to provide alternate parking. See ECC 15.550.040 for additional information about off-street parking.

City permit fees will vary based on the size and complexity of construction. Creation of new dwelling units requires payment of traffic and park impact fees. For recent ADUs, impact fees plus building permits have ranged between approximately $3,400 and $4,600. For more specific fee questions, please reach out to Community Development.   

It depends. Manufactured homes are allowed on City lots that allow single family housing. Units that qualify will have red insignia placed by the manufacturer in accordance with Labor and Industries and US Department of Housing and Urban Development (HUD) construction standards. A building permit is required for placement.

If you are looking to place any other structures, please contact building staff for additional guidance.

One EV-ready parking space is required for each dwelling unit with a private garage in the 2021 Washington State Building Code. If you add an ADU and garage space to your property, this requirement could apply to you project. For more information, see WAC 51-50-0429 or contact the Building Division.  

Consistent with Washington State requirements (RCW 36.70A.681), ADU building permits are exempted from frontage improvement requirements. Other new construction projects that involve ADUs along with other development may still require these improvements. For more information, see ECC 4.06.060, Ordinance 4971 or contact Public Works.

No additional off-street parking is required for the first ADU on a lot. If a second ADU is added, one off-street parking space is required in addition to those required for the principal unit. If ADU construction removes any of the previously required off-street parking for the principal unit (e.g. a garage conversion), the site plan submitted with the ADU building permit must show how off-street parking requirements are met for the entire site. Additional information is available in ECC 15.550.040. Please consult the Planning Division with specific site questions.