As of 10 September, Scottish Water was continuing work to restore normal water supplies in the Denny, Bonnybridge, Cumbernauld and Larbert areas after reports from customers about an earthy or musty taste or odour in the water supply. Monitoring of water supplies from the Carron Valley Water Treatment Works (WTW), which serves these areas, and the source reservoir confirmed that the earthy/musty taste or odour was due to geosmin, a harmless naturally-occurring by-compound associated with the breakdown of algae and other micro-organisms in the raw water sources. It has a distinct earthy, musty taste and odour and is present in some foods such as beetroot, spinach, and mushrooms. It also contributes to the strong scent that occurs in the air when rain falls after a dry spell of weather or when soil is disturbed.
The water was still being tested in Scottish Water’s laboratories and the company stressed that it was safe to use as normal and did not pose a risk to public health.
The latest sample results showed a significant reduction in levels of geosmin in the treated water supply. However, Scottish Water acknowledged that some customers would still experience the taste or odour issue with their water. [Source: Scottish Water Current update, accessed 11 September 2017. http://www.scottishwater.co.uk/contact-us/current-updates]
The origin and control of geosmin are further discussed in a 2007 study by Jüttner and Watson available at http://aem.asm.org/content/73/14/4395.