I would think the building or zoning department for the city would have that information. And there may be CC & Rs even if no HOA.

Christine Kankowski Temecula & San Diego Speak with your zoning authority in your city. They will tell you whether or not the current zoning will allow a multi-unit home. If allowable it could be automatic or require a zoning district change or possibility something as simple as a special use permit. Good luck with it.

Michael Setunsky nailed this one!

I would call the City zoning department.

In my area we have a planning and zoning department we contact at city hall

local zoning authorities

Good question, call the city I think

Non HOA, contact the city.

As Jeff Dowler and Michael Setunsky wote

easy go to city zoning department

have you considered researching the zoning laws?

Contact the authorities who have zoning authority over the subject property.

Christine Kankowski Temecula & San Diego - the next level is, town. Check with town officials for the same.

Check with the local governing authority

Contact the city offices. They will point you to the right person. 

I'm with Jeff Dowler on his answer!

Building Dept. County Clerks, Title Company and Zoning.

We have a planning commission in our town that has all the information on zoning and controls which would be the place I would start.

In any case you check with teh town or city hall's building and or zoning dept

Local zoning department should be able to help!

The planning department for the city or county would be a place to start.

In Charlotte, we would contact the Zoning Commission. One would have to petition (or file) for exception or approval.

Talk to the city.

The City building / planning / zoning department is where I would start.

And now maybe add an ADU or JDU - which might be a lot easier.

Download your local zoning and building codes.

Or hire an attny who is very skilled in this area.

Jeff Dowler ...spoke well

there are town zoning laws that can be found at the local town/city hall.... there are zoning maps with information concerning what's allowed; what allowed with special permits; and what is prohibited....

In your city, you probably have a zoning and permit department who would provide you with detailed local information. 

Contact your local zoning office.

I think that Jeff Dowler gave you the perfect answer.  And I would suggest you go in person to get the answer.  A

Township zoning officer is my 'go-to' for questions of that nature. 

City/County Public Works, Development Services, Planning and Zoning, Building Department or some such.

Village would have restrictions on that most of the time. They do that so people don't chop up their house into multi-rental units.

That's up to your local zoning board. If it's zoned single family residential, it's doubtful you can convert to multi unit. Parking, water and sewer, traffic, fire and rescue, etc, etc will all be factors.

You would go to the city or county authorities. Even in an HOA you'd need to check zoning requirements with the city/county authorities.