One of the exemplary filter systems described includes a bracket and a filter module that can be suspended from the bracket by a plurality of flexible supports. The bracket can support the filter system beneath the grate of a storm drain without the need for the filter system to be attached to the grate. The grate can be lifted out of the storm drain separately from the filter unit, which allows the filter system to be lifted without the added weight of the grate. When the grate has been lifted out of the way, a suitable fastener structure can be attached to the bracket of the filter system to make the use of mechanical lifting devices more convenient. The bracket can be manufactured to known dimensions, or it can be offered from among a set of brackets that are pre-configured for known storm drain dimensions or as a standard bracket that can be modified to fit the dimensions of a particular storm drain.