The key is the no HOA. If there's no HOA then there is no one to enforce a no-rent rule.
The county has a rule that only allows a certain number of PEOPLE to supposedly be living in the home, but if the people are family members then it is allowed.
The Realtor answer is check with an attorney or county official. If you're asking me though, I say go for it.
It depends on how many people you have in your house currently. There is a maximum number of people you can have inhabiting a house per Gwinnett County, but I honestly don't remember what this number is. Take a look at the Gwinnett County website and see if you can find it or call any local Gwinnett County police precinct - they'll know. Other than this, without a homeowner's association, you should be just fine.
If anybody knows any different, feel free to chime in.