conditional offer

Hi, folks! I am very excited to be making the transition from the private sector to civil service. I took a civil service exam for a clerical position and have received a conditional offer from Office A, a city agency. However, I also applied for a position at Office B, a county agency. I will not know about Office B for another week or so, but I have reason to believe I am a strong contender for the position.

Throughout the interviewing process, several things happened that make me a little wary of working for Office A - lack of preparation for the interview, the salary listed in the job posting was completely different than what they said in the interview/ the offer, other things like that. If I get it, the position at Office B would also pay considerably more. My question is, if I accept the conditional offer for Office A and go through the background checks but end up getting the job at Office B, will I be able to turn down the conditional offer without serious consequences? I know in the private sector either party can back out of a conditional offer, but I wasn't sure if there was anything different when local government is involved.