What are Variances on the Clean Water Act?

The CWA allows for variances from its requirements when circumstances justify exemption. There are two main exemptions available to existing sources, discussed below.

What is Economic Justification under the Clean Water Act

If a party cannot afford the BAT requirements, it must show that the technology employed to prevent discharge of pollution is all that the company can afford and that it will be effective in reducing pollution to within allowable levels. This variance effectively modifies the BAT for this party.

What is Process Justification under the Clean Water Act? 

A Fundamentally Different Factor (FDF) variance allows certain exemptions from the BPT permitting requirements. The EPA will consider the cost of implementation (such as facility or manufacturing costs), but the ability of the party requesting the variance to pay the cost is not considered.