You will have six exam attempts within a six-month period. Once you have attempted an exam six times, you must wait six months from the first attempt to register again.
You must wait ten days between each time you test before you will be allowed to test again, unless indicated otherwise by the applicable licensing board. You may test as many times as needed until you pass the exam unless indicated otherwise by licensing board requirements.
A licensing board may have specific retesting requirements. Before you register to retake an exam you should refer to the applicable state or jurisdictional Examination Information Bulletin by going to https://www.iccsafe.org/certification-exam-catalog