Noise
Quiet hours in Berkeley are 10pm to 7am seven days a week...in every neighborhood — on every street. If police receive a noise complaint, the officer initially responds to corroborate the "unreasonable" noise reported by the person who complained. The criteria include loudness, pitch, duration, time of day, and necessity of the noise. If the officer corroborates that the noise is unreasonable: 1st response - warning; 2nd response - up to $100 fine. (BMC 13.40.030)

Public Nuisance Gathering
If police are called because of a loud or unruly gathering or party, they will respond and investigate. If police observe something that makes them suspect that criminal activity is taking place, including underage drinking, they can enter the house, apartment, etc. to investigate. Their primary concern is public safety. A secondary question is whether the gathering constitutes a public nuisance (BMC 13.48.020). The criteria for a public nuisance includes:

• hindering the quiet enjoyment of significant portion of the neighborhood;
• ten or more people;
• excessive noise or traffic;
• obstruction of public streets by crowds or vehicles;
• public drunkenness;
• serving alcohol to minors;
• fights or disturbances of the peace; and/or
• litter.

If it is a public nuisance violation, you are subject to the Second Response Ordinance (BMC 13.48.050)