The security deposit can be used, for example, to cover:

unpaid rent,
unpaid utilities or other charges related to the tenancy,
damage to the property, furniture or equipment beyond normal wear and tear,
missing or broken items, keys, access cards or remotes,
extra cleaning if the property is not left in an acceptable and reasonably clean condition,
costs or fees that arise if you break or end the contract earlier than agreed, as described in your Tenancy Agreement.

You cannot use the deposit to pay your regular monthly rent or utilities during the tenancy. Monthly payments must still be paid on time, as agreed in the contract.