The feasibility of employing a centrifugal settling method for measuring the bound water content in waste activated sludge was investigated. The results demonstrated that, for such highly compressible sludge, the centrifugal settling test can only provide information about the cake compressibility and the method proposed by Matsuda and colleagues fails. A method combining vacuum filtration tests and centrifugal settling tests for estimating the bound water content is proposed and compared with expression tests. The agreement was close.