A fill limit vent valve configured for use with a reductant tank, the fill limit vent valve comprising: a valve body that defines an inner chamber and has a valve outlet; and a float having a float body configured to be received within the inner chamber and configured to sealingly engage the valve body; characterized by: a vapor permeable membrane disposed on the float body and providing an outer boundary of a float chamber provided on the float, the vapor permeable membrane configured to permit vapor to pass through while inhibiting liquid from passing through; the float further including a knob that defines a float passage; and the float movable between (i) an open position wherein vapor flows along a first flow path through the valve inner chamber around the float and out of the valve body and further along a second flow path through the vapor permeable membrane, through the float chamber, through the float passage, and out the valve body; and (ii) a closed position wherein the float sealingly engages the valve body and precludes vapor from flowing along the first flow path, wherein vapor still is permitted to flow along the second flow path through the vapor permeable membrane, through the float chamber, through the float passage, and out of the valve body. a valve body that defines an inner chamber and has a valve outlet; and a float having a float body configured to be received within the inner chamber and configured to sealingly engage the valve body; characterized by: a vapor permeable membrane disposed on the float body and providing an outer boundary of a float chamber provided on the float, the vapor permeable membrane configured to permit vapor to pass through while inhibiting liquid from passing through; the float further including a knob that defines a float passage; and the float movable between (i) an open position wherein vapor flows along a first flow path through the valve inner chamber around the float and out of the valve body and further along a second flow path through the vapor permeable membrane, through the float chamber, through the float passage, and out the valve body; and (ii) a closed position wherein the float sealingly engages the valve body and precludes vapor from flowing along the first flow path, wherein vapor still is permitted to flow along the second flow path through the vapor permeable membrane, through the float chamber, through the float passage, and out of the valve body. a vapor permeable membrane disposed on the float body and providing an outer boundary of a float chamber provided on the float, the vapor permeable membrane configured to permit vapor to pass through while inhibiting liquid from passing through; the float further including a knob that defines a float passage; and the float movable between (i) an open position wherein vapor flows along a first flow path through the valve inner chamber around the float and out of the valve body and further along a second flow path through the vapor permeable membrane, through the float chamber, through the float passage, and out the valve body; and (ii) a closed position wherein the float sealingly engages the valve body and precludes vapor from flowing along the first flow path, wherein vapor still is permitted to flow along the second flow path through the vapor permeable membrane, through the float chamber, through the float passage, and out of the valve body. (i) an open position wherein vapor flows along a first flow path through the valve inner chamber around the float and out of the valve body and further along a second flow path through the vapor permeable membrane, through the float chamber, through the float passage, and out the valve body; and (ii) a closed position wherein the float sealingly engages the valve body and precludes vapor from flowing along the first flow path, wherein vapor still is permitted to flow along the second flow path through the vapor permeable membrane, through the float chamber, through the float passage, and out of the valve body.