@Jacob Jenkot if it’s going to be a permitted ADU, the city may have a laundry list of requirements beyond plumbing.

If you can meet these conditions, then you should apply for a building permit.  

It's not really a MHP it's vacant land possibly with a permit to develop but as mentioned possibly not.

They'll be responsible for the work/permits.

@Alan Baumann in CA these are permitted through the State as factory built housing, which I believe likely follows in most other States as well.

- Cost of permits included?

Tenant shall permit reasonable access toLandlord, and any of Landlord’s invitees, agents, or contractors, in accordance withlocal statues and ordinances, upon receiving 2 days’ notice by mail, telephone,written notice or other means designed in good faith to provide notice.

What about permits?

As of right now, Airbnb’s are being regulated and as long as you get the proper permits etc, you are in business.   

The actual plans were not required for permitting in this area.