Making minor plumbing work
Small plants hydraulic predominantly take orders for minor plumbing work. They can be associated with connecting new sanitary facilities or carrying out small repairs. All such work can be carried out also by plumbers self-employed. You just have to reckon with the fact that the services contract with an independent plumber probably will prolong the work carried out. However, this should not affect their quality, and sometimes it turns out that the plumber running his own business applies doubly to perform the outsourced tasks themselves. They may rely on both the exchange of a faulty seal and at the connection of the new tap.
Wikipedia facts
Water supply and sanitation has been a primary logistical challenge since the dawn of civilization. Where water resources or infrastructure or sanitation systems are insufficient for the population, people fall prey to disease, dehydration, and in extreme cases, death.
Major human settlements could initially develop only where fresh surface water was plentiful, such as near major rivers. Over the millennia, technology has dramatically increased the distances across which water can be relocated, but the availability of clean and fresh water remains a limiting factor on the size and density of population centers, and is expected to remain so into the foreseeable future.
Źródło: https://en.wikipedia.org/wiki/History_of_water_supply_and_sanitation
Plumbing - from Wikipedia
Plumbing is any system that conveys fluids for a wide range of applications. Heating and cooling, waste removal, and potable water delivery are among the most common uses for plumbing however plumbing's not limited to these applications.1 Plumbing utilizes pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids.2 Trades that work with plumbing such as boilermakers, plumbers, and pipefitters are referred to the plumbing trade. In the Developed world plumbing infrastructure is critical for public health and sanitation.
Źródło: https://en.wikipedia.org/wiki/Plumbing#Systems