leak through (something)
Of a liquid or gel, to penetrate or soak (something) by slowly seeping or flowing through. My bottle must have a crack in it, because water has completely soaked through my bag. We've lined the interiors of the container with a polymer coating to keep the corrosive contents from leaking through.
leak through something
[for a fluid] to seep through something. Rainwater leaked through the roof. I was afraid that the crushed orange would leak through the paper bag.