The present invention provides a device in a multiwell plate that allows for one to obtain substantially all of the liquid that has flowed through the filter thereby reducing hold up volume. This is accomplished by forming at least one hydrophobic area in the hydrophilic filter in each well. After the filtration has occurred, air is allowed to enter the underdrain of the plate through the hydrophobic area(s) which causes any residual fluid held by surface tension to be released and to flow out of the underdrain to the outside environment.