This document specifies a method for the determination of drainability of flocculated sludges. It is applicable to sludge and sludge suspensions from storm water handling, urban wastewater collecting systems, urban wastewater treatment plants, treating industrial wastewater similar to urban wastewater (as defined in Directive 91/271/EEC) and water supply treatment plants. This method is also applicable to sludge suspensions from other origin. Anycase, it is applicable to all kinds of sludges provided particles are larger than 500 ?m in size. That is why the test should preferably be performed on sludges first flocculated.