The following content about ADU’s was provided by Dream House Draftinga Preferred Vendor of Team Lally. 
For More Information about ADU’s, we highly recommend contacting Dream House Drafting. 

ADU is an accessory or second dwelling unit that includes its own kitchen, bedroom, and bathroom facilities, and may be attached or detached from the primary dwelling unit.

The program was introduced as part of the Mayor’s Affordable Housing Strategy to combat the shortage of affordable housing on Oahu, especially rental housing. ADUs can help address this problem by allowing existing homeowners to build a second unit on their property even if the zoning on their property would not normally allow for the second unit. This allowance is limited to specific zoning districts (see list).

An ADU Pre-Check is conducted to determine if a lot is qualified for an accessory dwelling unit. This step should not be omitted under any circumstances. Many properties which meet the basic criteria for lot size and zoning may be disqualified for other reasons. During the ADU Pre-Check process the form is reviewed by multiple departments to make sure that the property will meet the public facilities standards with the addition of an ADU. An approved ADU Pre-Check Form does replace the building permit process and therefore does not grant the Applicant permission to construct an ADU without obtaining a building permit.

In July 2016 Mayor Kirk Caldwell signed Bill 27 (Ord. 16-019) into law.

Bill 27 was drafted by the DPP and passed unanimously by the City Council. The Ordinance includes provisions to provide fee waivers for ADUs for a period of two years, until June 30, 2018. The goal of these fee waivers is to encourage homeowners and contractors to continue the production of ADUs and increase the number of affordable rental units. The Ordinance also provides a permanent waiver of park dedication fees, the same as currently provided for Ohana Dwelling Units.

An Accessory Dwelling Unit can be built on:

A- Any lot zoned Residential






B- Country District with lot area of 3500 sf or more.

Number of ADU’s permitted on a single lot:

Only one ADU is permitted.

*Properties with multifamily dwellings, or which are part of a planned development housing, cluster, or group living facility are not eligible.

ADU difference from Ohana Dwelling Unit:

  ADU Ohana Dwelling Unit
Allowed Occupancy -persons who are related by blood, marriage, or adoption to the property owner(s)

-designated authorized representative(s),

-allowed for rent in unforeseen hardship circumstances (i.e., active military deployment, serious illness).

Strictly family members only
Size Limitation -max of 400 sf for lot size 3,500sf – 4,999sf

-max of 800 sf for lot size 5000 and more

*an ADU may not be rented for less than a six month period.

No size limitation
Off Street Parking Spaces 1 2

*An existing, legally established (permitted), accessory structure constructed prior to the effective date of the ADU Ordinance may be converted to an ADU and allowed to exceed the maximum floor area and/or be exempted from the off-street parking requirement through a zoning adjustment process. Completion of the zoning adjustment process requires added review.

The current rules require that a site plan and a preliminary floor plan of the proposed ADU be included with the completed ADU Pre-Check form. Dream House Drafting Inc. provides ADU design and routing of the Pre-Check form through the review process. Fees for ADU Pre-Checks start at $450.

If you would like to have Dream House Drafting Inc assist you in designing your ADU click here for the the ADU Pre-Check Form: adu-pre-check-form-2016-with-active-form-fields

Click here to download an ADU Pre-check Form from the Honolulu Department of Planning and Permitting website: http://www.honoluludpp.org/Portals/0/pdfs/construction/ADU%20Pre-Check%20Form.pdf