ADU or Rec Room

Some considerations for building an ADU vs Rec Room

• Regardless of what you call it: ADU or a Rec Room, if you obtain a building permit and the space contains a food prep area, as defined by the Dept of Env Services, the City & County of Honolulu will assess a  sewer base change, monthly. Meaning that you will likely be charged a sewer based charge for the primary dwelling + a sewer base charge for the ADU or Rec Room. 
• Fees are collected via you monthly Board of Water Supply (BWS) bill. On the back, it includes a sewer base charge, currently $77.55/mo per ESDU. When sewer usage fees and BWS fees are added, when you add an ADU or Rec Room, your monthly BWS bill will increase approx +/-$100 (depending on  actual water usage).
• An ADU is a legal second dwelling unit and adds more equity/appraised value than a Rec Room. An ADU may allow you to use the income from the 2nd unit to help qualify for or refinance your mortgage; lender requirements vary.
•  An ADU can be separately metered for water, electricity and gas, which makes it easier to pass on those costs to the tenant. A Rec Room cannot have separate meters installed by the utility companies, but some owners install privately owned and read submeters for water and electricity.
• If you wait (5+years) until you need it, you may not have the energy, resources, time, or health to see the project through. It takes a combination of all that and more to supervise a construction project in your own home.
• Codes will change in the future and may require additional retrofits before an ADU can be legally installed (i.e. fire sprinklers, solar water heater -- these are not currently required, but could be in the future). Future zoning regulations may restrict locations where ADUs are allowed, or the CIty Council may rescind ADUs entirely.
• Sewer capacity may be used up in your neighborhood and other infrastructure may no longer be avail to support new/additional ADUs in your area.
• Permit fees will increase in the future.
• Permit fee waivers expire 6/20/2018. ADUs permitted before then save by not having to pay the one-time sewer connection fee is currently $6,616 but has increased each year for the past few fiscal years and may increase again on July 01, 2017.

Caveat: The above information is provided for discussion purposes only and should be verified by the appropriate government agencies. The source of this information makes no warranties as to its accuracy.