421. Usual covenants in lease as to rates, taxes and outgoings.

The tenant usually covenants to pay all rates, taxes and assessments payable in respect of the demised premises during the term; and in cases of long leases, and sometimes also in short tenancies, the covenant is extended so as to include liabilities which are described by one or more of the words 'duties', 'outgoings', 'impositions', 'burdens', or 'charges'; and it is expressed so as to include such liabilities 'now or hereafter' imposed, and whether they are imposed 'on the demised premises or on the landlord or tenant in respect thereof