South West Water (SWW) took a £16m hit from this summer’s cryptosporidium outbreak, it has emerged.

According to a statement by SWW’s parent company Pennon Group, the utility firm made the loss as a result of the “Cryptosporidium water quality incident”, which had now been “resolved”.

Some 17,000 households in the Kingswear, Hillhead and Brixham areas were instructed to boil their tap water after a parasite got into the supply in May.

There were about 100 reported cases of cryptosporidiosis as a result of the outbreak, with dozens falling ill with symptoms that included vomiting and diarrhoea.

In its trading statement update, Pennon Group described the outbreak as “an incredibly rare event” for SWW.

The utility firm cleaned and flushed the water network 27 times to remove the parasite in addition to replacing sections of the 30-kilometre grid and installing special filters to restore supply to customers, with contractors working round the clock.

SWW accrued further costs by having to distribute bottled water to residents over an eight-week period and addressing compensation claims to affected customers, which could reach about £3.5 million, although the figure was not mentioned in Pennon’s statement.

SWW subsequently boasted that the cleaning regime “led to the delivery of the best quality drinking water in the world”, but at a recent meeting organised by the firm, some residents interviewed by this paper said afterwards that their experience had put them off and that they would no longer drink from the tap supply.