The heart of the eighteenth century Town of Birmingham lay on a north-east to south-west geological fault line, known as the Birmingham fault (see Fig. 1). To the south-east the bedrock consists of the red–brown marl called Mercian mudstone. To the north-west the bedrock was Helsby sandstone.
The impermeable marl of the Rea valley led to rapid drainage with consequent violent fluctuations in the run-off to the river. Just beyond the fault line, bands of marl within the sandstone prevented deep seepage of rain water and except during unusually dry periods offered a copious supply from natural springs and shallow wells. Water from these surface springs and shallow wells tended to be clear and soft.
This regular flow provided by Birmingham’s springs and wells provided a sufficient water supply for both domestic and industrial purposes until the mid-nineteenth century. The main public wells were one at the north end of Digbeth, very near St. Martin’s churchyard believed to have been called Holy Well, and another near the old parsonage between Smallbrook Street and Bromsgrove Street, at Ladywell,  probably formerly dedicated to the Virgin Mary and fed by two springs.  Together they were said to be
‘…. ..so extensive and powerful, that it is stated to be sufficient for the supplying the city of London with water.’ 
In 1815 it was said that
‘… numerous people find their advantage in conveying that useful article [soft water] in carts, and innumerable others in carrying it with a yoke and two buckets, to those who want it, which they sell at the rate of from ten to twelve gallons for one penny, according to the distance.’ Continue reading