How long did the Roman aqueducts take to build?

Construction time for the aqueducts depended upon several factors, so there was no set time for them to be completed. The engineers had to take into consideration distance, landscape, and weather along with the number of men needed to complete the project and, especially, how many bridges needed to be built to carry the water over valleys of to maintain the sloping gradient needed to keep the water moving. The construction of bridgework was the most-time time consuming part.