The aqueduct bridge of Segovia starts at the Casa del Aqua. A 42 m long section of wall is followed by a 683 m long bridge of arches in a section that changes direction several times. The corners where the bridge changes direction have not been strengthened in any way. A first section of 75 singe arches is followed by the most famous section of two tiers and 44 double arches that crosses the valley close to the city wall with a maximum elevation of 29 metres. The aqueduct bridge is completely built in opus quadratum, large blocks of granite without the use of cement. This method of construction is probably imposed by the lack of limestone to make cement in this part of castille, but helped to preserve the building by making the bridge flexible to survive small earthquakes, settling and small motions due to wind and temperature gradients. The ornamentation of the bridge is sparse and restricted to imposts along the tops of the spandrels, at the springing of the arches, and in the piers. The imposts were probably meant as ornamentation, but also to carry the formwork to build and maintain the bridge. The diameter of the piers decreases stepwise by one Roman foot upwards at the imports from 3 x 2,4 m at the base of some pillars to 2,5 x 1,8 m at the top. Because of the decreasing diameter of the piers, the arches increase in span from 4,5 m to 5,1 m at the top.
The aqueduct is special in that nearly every pillar and spandrel has a different design. Some arches have a common springer, others have spearte but touching ones, and the base of many of the spandrels is different. This may partly be due to later reconstruction, but especially in the two tier section of the bridge, the design seems to be original. This would imply that the bridge was not designed in advance in great detail, but that arches and spandrels were designed on the spot with the bocks that happened to be available and designed as construction progressed.