Generally an affidavit should be notarized. For purposes of recordation or acceptance into a court of law, it needs to be attested to/sworn to before an officer of the state, i.e. a notary public. However, many state agencies, such as DOT, will accept affidavits that are not notarized. Short answer is - it depends on what you intend to do with it. Most likely it should be notarized.