There was practicaly no improvment in water supply systems in midle ages. In Germany, water works were constructed in 1412 and pumps were introduces in 1527 in Hanover. Franciscan monk constructed aqueduct of Zempola in Mexico in the middle of 16th century. In 1582, a pump was erected on the Old London bridge for the supply of water from the Thames. The water was conveyed through lead pipes.
References: Punmia BC, Ashok J, Arun J. (1995). Water Supply Engineering