[quote=gzz]SDR, running utilities to your ADU could either be fairly simple or double the project cost, if your current setup is too small to be simply extended to the ADU.

I asked a developer about preserving my house and building a triplex behind it versus just tearing it down for 4 units. He said completely new hookups are needed and building around an existing one is extremely expensive and kills the economic advantage of building 3 instead of 4 units.[/quote]

I’ve got existing gas lines back there for a fire pit and barbecue I can tap into. Planning to put solar on the roof and there’s a separate 220 amp sub panel in back for a spa I removed years ago. I think plumbing will be bigger issue but master bath is in the back corner on that side so hopeful I can tap in there. also when the house was built new, my house was the last phase of the project. When I arrived to do my walk-through there was a set of blueprints sitting in the garage that I knew they would not be needing anymore so I threw them in my trunk. I have a complete set of blueprints from my house so locating anything I need to tap into won’t be a mystery.

with all that said I’m hoping to build something really nice, in fact while smaller it will be nicer than my house and will be my eventual home. I figure $300/sf to do what I’m thinking on a 2/2 1000 SF ADU. right now at 700 square-foot one bedroom condo near me runs about 350 K plus taxes and HOA. Seems like a no brainer long term