Public Release: 

Leaky pipes can allow contaminants into our drinking water

University of Sheffield



It had been assumed that only clean water from the leak would be sucked in, and that even if contaminants were sucked in these would simply be ejected once the pressure returned to normal. The new study has shown, however, that groundwater from around the pipe - which often contains harmful contaminants - can be sucked in, remain in the pipe and travel on through the network.



Professor Boxall says: "Previous studies have shown that material around water pipes contains harmful contaminants, including viruses and bacteria from faeces, so anything sucked into the network through a leak is going to include things we don't want to be drinking.

"Many of us will have had a 'dodgy tummy' in the past that we couldn't quite explain, often putting it down to something we'd eaten. It now seems possible that some of these illnesses could have been caused not by food, but by water."



Co-researcher Dr Richard Collins says: "Our research shows that contaminants that enter through a leaking pipe could be reaching consumers' taps, and although this will be at very low concentrations, it would fail the safety tests if detected. We also believe that microorganisms, including pathogens, which enter the network in this way could attach to the inner surface of the pipe and multiply. If they are later dislodged by another change in flow, they could then reach our taps in higher concentrations."



The UK regulator, Ofwat, deems that leaks within the UK water network have been at an economically sustainable level for the last 15 years - which means that the cost of finding and repairing the leaks would cost more than the value of water lost.

"It's not feasible for the water industry to stop all leaks, and most of the time, leaks don't pose a risk," says Professor Boxall. "This is why the water industry is now focusing on preventing the pressure changes which enable contaminants to enter the system, rather than eliminating the leaks through which they enter."

