The ecodrain must be installed along the drain line. What this means is that you must have access to the drain pipe that exits from the shower. Beneath a shower drain, you will find a p-trap. This is a curved section of pipe that seals the shower from the sewer. The ecodrain can be installed at any point beyond the p-trap, ideally as close as possible to the shower. If you have a basement or crawl space, the pipe might be exposed (visible) on the ceiling of either.