Project Appreciation and Objectives
Follow-up investigations carried out by water companies following coliform occurrences are often unable to provide valid reasons for their occurrence in drinking water. Recently, the Drinking Water Inspectorate (DWI) has been critical of some of these investigations and their conclusions. It has requested that water companies exercise due diligence and investigate these occurrences more thoroughly.
Currently, there is no consensus view for the industry on what would represent a thorough investigation of a coliform occurrence and water companies have developed their own individual responses.
This project has collated water company responses to coliform occurrences and, with the agreement of participants and the DWI, devised a standard operating procedure for investigation and remediation. The DWI provided the project with anonymous examples of what it considered to be good and poor investigative follow-up reporting.
Benefits to Clients
- Demonstration of due diligence to DWI.
- Reduction in lengthy and costly investigations when responding to the occurrences of coliforms.
- Collate water company procedures for, and experiences of, responding to coliforms in drinking water and review examples of good and poor investigation provided by the DWI.
- Review the individual procedures for consistency of approach and develop a procedure that demonstrates good practice for investigating the cause of coliform occurrences.
- Agree a standard procedure for investigating coliform occurrences between the participants and the DWI.
- ADocumented and consistent procedure for investigating and reporting occurrences of coliforms agreed with DWI.
- Detailed final report.
- Dissemination workshop
Related WRc Work
WRc has considerable expertise in this field, dating back to the early 1990s, beginning with work for FWR on formulating criteria to predict the likelihood of detecting coliforms in water supplies. More recent work includes:
- A study evaluating the usefulness of bacteriological indicators. UKWIR (2004-2005).
- Partner in EU FP5 Microrisk Programme - the application of quantitative microbial risk assessment in water supplies. (2002-2006).
- Portfolio project - Best Practice Manual for Sampling Microbiological Quality of Drinking Water (PT2118), April 2001.