Depending on how you define plumbing, we have had some sort of plumbing for several thousand years. We were wishing we had it before that, of course, but what could we do without plumbing and plumbers? As long as we were traveling in small bands, hunting and gathering, it was not much of a problem, as we would just move on and leave the problem behind. But when we started to settle down, plant, tend fields, harvest, and store grain, we had to figure out some system to deal with it all.
Those old castles that you might visit if you make a vacation trip to the isles of the United Kingdom often had sanitary sewer systems of one sort or another. Those go back a few thousand years as well. They may have even taken care to keep the castle sewage out of the moat, so that the water could be kept clean and fishes caught out to be served on Fridays. Those old castles also had some of the earliest attempts at what we might call a water closet, though mostly without the water. To be exact, it would have been a sort of alcove into the wall, with a hole leading to the under-the-castle sanitary sewage arrangements. That would be an improvement on a bucket beside the bed in milady’s chamber, I’m sure we can agree.
But now we’ve arrived, with whirlpool tubs, low flush toilets, and fancy showers that come at you from all angles. Hooray for us! And Hooray for the plumber that install all these conveniences, and keep them flowing and flushing as well.