Baltimore City rentals and uninvited guests

I have a 3 apartment MFD in Baltimore city. A 1br, 2br, and 3 br.

Of course the tenants have not paid rent in 4 months.

What is worse are the water bills I am getting each month. $900, $800, $1800 for July, August and September.  I live out of the country, and have a property manager for the unit.

I paid a visit several weeks ago.  There are 4 people living in the 1br.  8 people living in the 2br.  7 people living in the 3 br.  Each lease lists one tenant.

I want to get rid of the ‘guests’ living rent free there.  I have ‘No Trespassing’ signs posted on the property.

As I understand Baltimore City law, I need to give each of the tenants notice about telling the guests to move out.  And then call the sheriff to have them arrested for trespassing if they do not vacate the premises.

Does anyone in Baltimore City have experience with this situation?

Regards