David Harris, Managing Director of Water Services at South West Water, explains how the water company is continuing to learn lessons following the cryptosporidium outbreak in Brixham - one of the key lessons learnt is the importance of early detection.

David Harris: It has been over nine weeks since we lifted the final customers from the boil water notice that impacted people in the Brixham area following the outbreak of cryptosporidium in May. We deeply regret that this incident occurred and as part of our ongoing work in Brixham and across the wider region we are determined to understand exactly why this happened, and how we can make sure it never does again. Our top priority will always be protecting our customers and providing the best quality of water you all rightly expect.

In Brixham and Kingswear, water is treated at Littlehempston Water Treatment Works which takes its water from river sources near agricultural land. Because of this, we test every single day for cryptosporidium in this untreated water. We also use advanced treatment processes at that site and test the water as it leaves the treatment works and enters our water network to make sure it meets the highest quality standards.

We do further regular testing for many contaminants at service reservoirs, including the Alston, Hillhead and Boohay service reservoirs. We test for a range of contaminants, including those that would be markers for the presence of cryptosporidium. We also monitor issues across the network and have teams that look for changes in pressure, potential bursts and respond to customer contacts around how their water looks and tastes to see if there are any changes we need to be aware of.

So how did this issue occur?

In Brixham this May, unfortunately despite all the monitoring in place, cryptosporidium was able to enter our clean water network. We identified the site that caused the issue, we isolated and fixed a damaged asset, and we are continuing our investigation into the source on that site.

Our teams worked around the clock for eight weeks to provide bottled water to thousands of customers, isolate the cause of the infection and thoroughly clean and protect our network.

We flushed over 34km of water pipes 27 times at high velocity to clean network pipes and remove cryptosporidium, and carried out 17 phases of ice-pigging and swabbing – a more aggressive cleaning approach. We also installed ultraviolet solutions and microfilters to provide barriers to remove cryptosporidium within the network. We then lifted the boil water notice in line with the principles agreed with public health partners, including the UK Health Security Agency and the local authority's Environmental Health department.

What have we learned?

Thankfully incidents such as this are extremely rare both in our region and across the UK as a whole but that does not take away from the impact this caused to our customers. The public water supply in the UK is among the most tightly regulated in the world and this has led to the delivery of the best quality drinking water in the world since those regulations were introduced in 1989. However, we need to continue to work hard every day to be sure we maintain those standards.

We have already learned valuable lessons from this incident and are taking action to ensure a safer and more reliable water supply for the future. We will also share these learnings with the rest of the UK water industry to help prevent similar outbreaks from happening anywhere else.

One of the key lessons we have learned is the importance of early detection. Our processes did not detect this outbreak early enough and so we need to look at improving our monitoring technologies so contaminants can be detected more quickly and accurately.

We are identifying opportunities for enhanced investment within our network to further minimise the risk of future contamination. In Brixham, Hillhead and Kingswear, a filtration system and ultraviolet treatment has been installed to provide long-term additional protection for our customers.

We have worked tirelessly to address the cryptosporidium incident and to implement measures that will prevent such incidents in the future. As well as continuing our own internal investigations we are fully co-operating and supporting the Drinking Water Inspectorate’s investigation into what happened.

We will continue to work hard to make improvements and rebuild trust within the Brixham community so that everyone can have confidence in the water we supply.