The jetting process is expected to last another week and is costing Scottish Water £18,000. It follows repeated complaints from local residents about flooding from overflowing drains caused, the quango believes, by a build-up of silt in the sewer system.

"It has been a nightmare for residents and this operation will go some way to providing a solution," said Scottish Water's regional communities manager, Bill Elliot.

"I have been liaising with Selkirkshire councillor Vicky Davidson to find a long-term solution ... which may require a phased approach," he told The Wee Paper. "We will carry out CCTV investigations to see if the silt removal has been a success and decide if additional measures are necessary. We understand the frustration caused to residents by such flooding incidents."

For its part, Scottish Borders Council will clear surface water drains in the area.

The problems at South Port have prompted Scottish Water to launch a region-wide campaign for Borderers to keep sewers free by bagging and binning sanitary items and not flushing them down the toilet. Items include cotton buds, nappies, condoms and sanitary towels.

"Although a silt build-up is responsible for the blockages at South Port, our waste water system is just not designed to cope with these items." said SW regional manager Craig Lawson. "Grease and oil from commercial and domestic kitchens can also lead to harmful blockages to the network."

Meanwhile, a major investment at the Howden Water borehole site near Selkirk will provide clearer, fresher drinking water for the people of the town, it has been claimed.

Scottish Water has announced it will spend around £10million over the next two years constructing a new membrane plant at the site on the road to Ettrickbridge.

"This will improve water treatment at the facility and will benefit nearly 17,000 people in the central Borders, not only in Selkirk, but also in Melrose, Earlston, Lauder and parts of Galashiels," said Mr Lawson. "We are also building a 12-million litre clear water storage tank at Howden – enough to fill every swimming pool in the Borders."

The construction work, part of a £25million capital investment across the Borders, will be carried out by Biwater Leslie who will also refurbish the water treatment works at Roberton – one of three plants providing water for 42,000 people in Hawick, Jedburgh, Kelso and St Boswells. The other two reservoirs, at Dodburn and Acreknowe, will be phased out by the end of next year.

"This investment will provide a clearer, fresher drinking water supply, fit for the 21st century," said Mr Lawson.