Vaping is becoming pretty popular. :-)

It could be a good accessory apartment if there was access from the back

Most zoning laws in most cities do not allow accessory dwelling units, (ADUs) in neighborhoods with single family zoning.  

(iv) The junior accessory dwelling unit complies with the requirements of Section 65852.22.

Exemptions include "Housing accommodations in which the tenant shares bathroom or kitchen facilities with the owner who maintains their principal residence at the residential real property.(5) Single-family owner-occupied residences, including a residence in which the owner-occupant rents or leases no more than two units or bedrooms, including, but not limited to, an accessory dwelling unit or a junior accessory dwelling unit."

If the lot is big enough with the rental you already own, you can add an "accessory dwelling unit" and a "junior accessory dwelling unit" on the property you already own, you can convert a garage, etc. 

My turn to chime in.Headline of the ad says “Nice Clean 3/1 UPSTAIRS unit in this charming Duplex”First Sentence of the ad and the last two sentences of the ad as well as halfway through the ad it says “No Smokers of any kind, no vaping, no e-cigarettes, no cigars, nothing .

thanks guys theres other form than smoke/vape?

I made sure the buyer knew about this.In the town I live in they allow accessory units restricted to family member use in some zones. 

@Dan TannerDogs $100 monthlyCats $50 monthly (& I like them way less)Smokers, (& vape) outside only.