By harnessing the power of high tech radar sensors beneath more than 20000 sewer manholes, Southern Water has prevented 55 pollution incidents in two years, helping to cut incident numbers by 35 per cent in the past year.

Southern Water has the UK’s first digital sewer network - the success of the programme means another 10,000 monitors will be added.

sewer level monitor in manhole

Left unchecked, the manhole would have overflowed causing pollution

Alex Saunders, head of wastewater networks at Southern Water paid tribute the work of the proactive maintenance teams which uses the sewer level monitors to detect when fatbergs are starting to form in pipes.

“On top of the important cut in pollution incidents is the impact on customers. 498 garden floods have been prevented and better yet 48 homes have been spared the misery of internal sewer flooding,” he said.

Blockages from fat, oil and grease and ‘unflushables’ such as wet wipes and sanitary products are the biggest cause of pollution incidents – responsible for 28 per cent last year.

Sewer level monitors are radar devices fitted beneath manholes in high risk areas. They constantly measure the level of wastewater flowing beneath them. Machine learning then helps Southern Water to understand how flows behave normally – in dry weather, wet weather and in the morning and evening ‘wastewater rush hours’.

If the level starts to creep up this will be flagged as a sign that a blockage is starting downstream of the monitor. Proactive teams can be dispatched with heavy water jets and other tools to clear the growing fatberg before it causes a serious problem.

The monitors are also being used to monitor for high ground water pushing its way into pipes and helping the water company prioritise areas at risk of groundwater flooding for work to seal sewers and customers’ pipe against water getting in.