This study analyzes the costs borne by Malaysian palm oil mills (POMs) in order to reach standard levels. A number of studies have been conducted on Malaysian palm oil mills; however, none has obtained the marginal abatement cost (MAC) through an estimated total cost function. More particularly, as far as inflation is concerned, the effluent-related fee and effluent charge specified have not been revised within the past two decades. In addition, to our knowledge, there has not been any study comparing MAC to the mills of the two different methods of disposal, namely watercourse and on land. Our results show that, to force POMs to meet the standard, the effluent charge must be set higher, equaling the MAC. While the results show the existence of economies of scale in abatement activity, setting the effluent-related fee equal to the MAC may encourage mills to further abate their water pollution.