Two independent filter housings are skid-mounted and manifolded, making one filter unit active while the other is out of service. However, both filters can also be in service at the same time. Inlet and outlet connections are provided on each end of the skid, and legs are attached to cross supports on the skid. These units can be used for filtering a range of industrial and commercial process fluids, groundwater discharge from construction sites, stormwater or urban runoff.