"Watts WP5-50 Premier Five-Stage Manifold Reverse Osmosis Water Treatment System" sells for $170 on Amazon. Replacement filter kit for it sells for $30 - pretty cheap. Now, suppose I have got a low key electro-mechanical workshop and I want to go into business competing with Watts making these machines. Obviously I cannot make my own membrane filters, so I would just buy the replacement kits. How hard would it be to produce a device capable of using an existing replacement filter kit to filter water like the OEM device does? Will this require some additional super-dooper complex membranes which Watts does not sell in kits, thus making it impossible for me to replicate it (without actually extracting such components out of legit OEM devices)? Or will it be just a run-off-the-mill electrical pump device with water-tight joints that can be assembled from widely available components?