A water filter cartridge has a cap with radially oriented first and second (either inlet or outlet) flow channels on first and second generally cylindrical portions. First and second seals encircle the first flow channel on the first portion and third and fourth seals encircle the second flow channel on the second portion. The second and third seals form a void volume during use which may be accessed by a vent path to eliminate moisture or to test for or indicate leaks. The radial flow paths reduce axial, push out forces on the filter cartridge and allow smaller locking tabs to be used. The first seal forms a top void volume during use which may be accessed by a vent path to eliminate moisture or to test for or indicate leaks.