As Bradford has no major rivers running through it, the city needed fresh water for drinking and to be able to process wool (fulling).

Scar House Reservoir was started in 1920 with direct labour under the control of James Watson's successor, Lewis Mitchell, and completed in 1936.

[5] The aqueduct starts downstream of Scar House Reservoir, after the screening chamber on the south bank, a short distance east of the dam, at Ordnance Survey grid reference SE 06820 76880.

The Aqueduct tunnels under Rain Stang hill for 2,486 yards (2,273 m) at a depth of 484 feet (148 m), and re-appears at Armathwaite Gill.

The aqueduct then tunnels below Greenhow Hill, 380 feet (120 m) below the summit, for 6,204 yards (5,673 m)[10] before re-appearing at Skyreholme, near Appletreewick.

It then heads across open land again, crosses the A59 at Bolton Abbey Railway Station and runs adjacent to Chelker Reservoir above Addingham.

[18] A pump was installed at Barden on the River Wharfe that is capable of abstracting 5,000,000 imp gal (23,000 m3) of water a day into the Nidd Aqueduct and bolster the supply to Bradford.

Ten years later, the original pipe was found to be 30 inches (760 mm) out of alignment where it runs underneath Bingley South Bog.