Late Fees

[Adam Schwartz]

In Montgomery County, MD the law states that interest cannot be charged until rent is late by 10 days. If an owner wants me to write language into a lease that late fees will be charged if received after the 5th of the month, which would prevail in a court of law - the lease language a tenant agrees to, or, if a tenant challenges after the fact, the rule/law of the County? Any help would be appreciated.