A low cost packaging method, based on aluminium layered laminate sealing technology, is presented in this paper for the environmental hardening of planar waveguide splitters, filter WDM assemblies and other non-robust passive devices. Since the former two passive components will play a prominent role in PON networks and their upgrading scenarios, we questioned their long term reliability in uncontrolled outside plant environments by investigating their behavior in environmental testing as defined by Telcordia 1221. In particular, the optical performance of planar splitters and filter WDM assemblies from randomly chosen suppliers was monitored during temperature cycling and long term damp heat testing. A comparison was made between devices as packaged by the supplier and devices packaged in our Al laminate packaging. Although the packaging of planar waveguides has improved over the last years, our study convincingly demonstrates failure modes in the non-laminate packaged planar splitters. In addition, dramatic failures were also observed in filter WDM's assembled in modules for wide WDM, coarse WDM and dense WDM, which raise serious concerns about their long term environmental reliability. The laminate packaged devices however all pass the severe test conditions, exhibiting a better stability. This favors the use of our packaging method for the integration of planar splitters and filter WDM based assemblies in outside plant network elements.