Domestic workers are protected under federal labor law and, therefore, must be paid time-and-a-half for all hours worked over 40 in a 7-day workweek. (Exception: Live-in employees in most states do not have to be paid overtime rates, but they must be paid for each hour they work).  This is true whether you pay her on a salary or an hourly basis.

If you have agreed to a salary for a workweek of more than 40 hours, it is legal to include overtime into the salary.  To do this legally, however, you must include the rates of pay (regular and overtime) in your employment agreement to clearly show how the salary was computed -- and it must be signed by the employee.  If you need help with the math or the legal language, just give us a call.