rental property late fees

[Lorie Madruga]

hi I'm new to this forum. I am looking at a existing investment.  I am seeking help on the laws of late fees. I have been in discussions with a private owner about purchasing a apartment dwelling. Going through some of the paperwork I noticed that the current landlord is charging the tenant late fees on their existing rental agreement which is $40 for the first day late and $3 per day thereafter. He gives a 5 day grace period for for rent, but if they're  late on the 6th day he charges the $40 on the first day of the month and $3 thereafter , so if a tenant was hypothetically late 25 to 30 days late , charges can run up to 130 per month. I was reading some of the laws in California and the most I seen for a late charge of 10% of the rent. Most of the units he rents out or $650 per month which would make your late fees $65 I wanted to see if this is legal the way he has it set up? or do I need to restructure everything?  if I do and if I do end up buying complex? Any legal help you could assist me with we greatly appreciate it Thanks.