City of Hanover issued the following announcement on May 7.
Good news! The Playgrounds are open!
The City of Hanover is removing official restrictions on playground use and opening them to the public starting today, May 6th. Note that the City cannot guarantee that surfaces are clean of COVID-19 or any other unseen virus/contaminant. Use at your own risk and follow all applicable guidelines per the CDC and MDH. Thank you for your patience waiting for the playgrounds to open!
Original source can be found here.
Source: City of Hanover