…….and the answer is: Almost always “yes”. 
Whether you have to or not has nothing to do with what crime you have been accused of, whether you have a criminal record, or whether you have a lawyer (a good one or not). The requirement that a defendant waive his right to a preliminary hearing in order to be eligible for ARD is based solely on what county the case is in – be it Montgomery County, Chester County, Delaware County, Bucks County, Philadelphia, or parts beyond – and nothing else.
While it does seem unfair that a defendant give up his right to test evidence against him – sometimes even in a case where he or she may actually be innocent, county District Attorney’s Offices across Pennsylvania are making waiving the preliminary hearing a necessary step in the ARD process. The stated rationale for this policy is that prosecutors want to see individuals “accept responsibility” for the crime they’ve been charged with in order to be considered for ARD. In their eyes, a person exercising their constitutional right to a preliminary hearing is not “accepting responsibility” – they are putting up a fight. The nerve! Of course this is all crap. The real reason the requirement exists is that prosecutors merely want to save money, time, and effort by requiring that defendant’s surrender this right. No more and no less.
That’s said, Chester County was at the forefront of requiring waivers. That has been their rule forever. Bucks County followed suit this year and Montgomery County did the same just this month. Philadelphia County does not hold preliminary hearings. Of the counties in the greater Philadelphia area, that leaves Delaware County as the ONLY county where you can actually have a preliminary hearing and still be considered for ARD. For all first time offenders, whether it be for a Pa. DUI or for any other crime, it is advisable that they consult a criminal attorney that is well versed in the ARD rules in a particular county. Good luck.