Does my employer have to pay me for drive time between job sites?

It depends, but probably "yes."  Assuming you report to work at a certain time each day, and that you clean a residence, then travel to the next location, clean that residence, travel to the next, etc. The time spent driving between the first residence, and the last (and all of those in between) would be considered "Time Worked" under the federal wage and hour laws.  That answer assumes you are an employee of the cleaning company.  If you are a true independent contractor, different rules may apply.