There is no definitive answer to this question, as it can depend on the size and type of washer in question, as well as the amount of laundry that needs to be washed. However, a good rule of thumb is to not fill the washer more than two-thirds full, in order to allow for proper washing and rinsing. Additionally, overloading the washer can cause it to vibrate excessively and may lead to damage over time.