Renting a home with only one bathroom

We’re closing on a lakefront home in Maine soon with 3 bedrooms & 1 bathroom. It actually has a bonus room in the semi finished basement being used as a bedroom now but we won’t set it up as a bedroom. It will sleep 5 max which still sounds like a lot of people for just one bathroom. It also has a septic tank so we are cautious about renting to too many people at once and having to deal with septic issues.

Anyone else rent a place with just one bathroom? What is your max guest count? I’m wondering if 4 is more reasonable.