Not only do plumber apprentices have to complete their training and education to receive their licenses, they also are required to pass a criminal background check and carry liability insurance. Hiring just anybody can make you vulnerable to fraud since unlicensed plumbers might not know what they're doing or could pretend to fix something and end up charging you for the incomplete work.
Plumbing reached its early apex in ancient Rome, which saw the introduction of expansive systems of aqueducts, tile wastewater removal, and widespread use of lead pipes. With the Fall of Rome both water supply and sanitation stagnated—or regressed—for well over 1,000 years. Improvement was very slow, with little effective progress made until the growth of modern densely populated cities in the 1800s. During this period, public health authorities began pressing for better waste disposal systems to be installed, to prevent or control epidemics of disease. Earlier, the waste disposal system had merely consisted of collecting waste and dumping it on the ground or into a river. Eventually the development of separate, underground water and sewage systems eliminated open sewage ditches and cesspools.