There is an ongoing question as to how ships will demonstrate their ballast water is in compliance with regulations when they pull into ports as well as how port State control might check this. Making a direct measurement of compliance can be a long process requiring skilled scientists and resulting in costly delays. Several companies have developed rapid compliance tools which make indicative measurements based on well-established scientific methods. The question is – what is being done in the maritime industry to show these indicative measurements are truly a good indication of compliance with the ballast water regulations? This paper presents why the 10-50 μm sample size is being used for these indicative measurements, the types of data presented by indicative tools, an overview of the various instruments being developed, and then most importantly, what organisations are validating compliance monitoring and what is the current status of their validations. In addition, some organisations who have already adopted using compliance monitoring in their processes and how they are using it will be included.