How NOT to Install a Water Filter

We recently investigated the cause of failure of a water filtration unit that cracked and caused an extensive amount of water damage to residential dwelling.  During the course of the investigation, it was determined that a whole house water filter unit had been installed in a cabinet beneath the kitchen sink.  This location is perfectly acceptable as were the piping connections that were made to connect the unit to the cold water supply line.  However, when the upper and lower halves were assembled, the pieces were put together with pipe joint compound.  This is absolutely unnecessary and amounts to an improper installation.  The filtration unit comes with an O-ring that is intended to fit between the halves and seals any gaps while preventing water leakage.  Although the unit failed as a result of over pressurization,  the presence of pipe joint compound indicated that the filtration unit had been improperly maintained.  The failure of the unit is shown in the photographs below.