According to Southern Water, blocked sewers are the single biggest cause of pollution incidents, but AI has now cut internal flooding by 40% and external flooding by 15%.
The water company says it has about 32,000 sewer lever monitors that can check on flows and spot anything out of the ordinary which might indicate a blockage or leak.
Mr McElhinney said: “Most customers do not realise the average suburban sewer is only the diameter of an orange or a tennis ball.
“It doesn’t take much cooking fat to combine with other ‘unflushables’ such as sanitary products, wet wipes or even ear cleaning sticks, to form a fatberg,” he added.