There are four separate places to look, and you check all of them because any one can stop you.
First, the zoning ordinance for the district the property sits in. Find the definitions section and read how the code defines family or household, then find the occupancy provisions. Many single-family districts allow a family plus a small number of unrelated adults, and caps of two, three, or four unrelated people are common. This varies by city and state, and how a given cap applies to your arrangement is a question for a local land use attorney rather than something you decide from the text.
Second, the property maintenance or housing code, which is usually a different chapter. That's where minimum square footage per occupant and bedroom requirements like egress windows live. A room without legal egress isn't a bedroom you can rent.
Third, rental licensing or registration, if your city runs a program. Ask whether four separate leases in one dwelling is registered as one rental or as rooms, and get the answer by email.
Fourth, the HOA. The recorded CC&Rs are the main document, and you want the amendments too, plus the rules and regulations the board has adopted, because boards often add leasing restrictions that never appear in the original CC&Rs. Request the full resale or estoppel package and read the leasing section closely.
The question people forget to ask the HOA is about minimum lease terms and occupant approval. A six month minimum term, or a rule that all occupants must be listed on one lease, kills per-room renting without ever using the words room rental. If the docs are ambiguous, ask the manager in writing what the board's current position is and keep the reply, because a verbal from a board member won't help you later.