plumbers must be asked directly what they charge hourly and if that is in addition to a service charge. The two are separate and I think they have gotten away with outrageous charges because of the potential of water damaging homeowner structures. I had a plumber (not Home advisor) come and replace a part in my kitchen sink that was under warranty---the spray nozzle had been leaking...He charged me $85.00 for 15 minutes of work and I will never use Mr King again.
Plumbing originated during ancient civilizations such as the Greek, Roman, Persian, Indian, and Chinese cities as they developed public baths and needed to provide potable water and wastewater removal, for larger numbers of people. Standardized earthen plumbing pipes with broad flanges making use of asphalt for preventing leakages appeared in the urban settlements of the Indus Valley Civilization by 2700 BC. The Romans used lead pipe inscriptions to prevent water theft. The word "plumber" dates from the Roman Empire. The Latin for lead is plumbum. Roman roofs used lead in conduits and drain pipes and some were also covered with lead. Lead was also used for piping and for making baths.