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Faecal bacteria in some Otago waterways is causing a mixed bag of water quality readings this summer, but the results have drawn limited response from the Otago Regional Council.

Many waterways have had elevated E. coli levels this summer, including five that have red or "unsuitable for swimming gradings" at present.

They are the Kakanui estuary; the Kakanui River, at the Clifton Falls Bridge; the Taieri River, at Waipiata; the Waikouaiti estuary; and the Waikouaiti River, at Bucklands.

E. coli bacteria come from the intestines of people and animals and are introduced to the environment through faeces and can cause diarrhoea, nausea and occasionally vomiting, fatigue and fever.

The presence of faecal indicator bacteria indicates other harmful pathogens may also be present.

Warning signs have been put up at various times this summer at some sites with elevated E. coli levels, including Queenstown Bay, which has had a mix of "green" (suitable for swimming), "amber" (caution advised) and "red" (unsuitable for swimming) gradings since December 1. Its grading yesterday, from its most recent water sample, on January 10, was amber.

Approached for comment earlier this week, an ORC spokesman referred back to a statement the previous week from Queenstown Lakes District Council chief engineer Ulrich Glasner, who said the Queenstown results could be caused by high winds creating choppy conditions on the lake.

Alexandra man Gavin Dann, a retired science teacher and former chairman of Central Otago's Last Chance Irrigation Company, said in a subsequent letter to the Otago Daily Times that it was "a load of old codswallop" to claim E. coli was caused by windy conditions.

"Ask any person with a modicum of biological or medical knowledge ... will tell you [E.Coli] is a type of bacteria that normally lives in the intestines of people and animals."

An ORC spokesman again provided no comment yesterday, and referred questions to Mr Glasner, who could not be contacted.

Three other Otago waterways have "amber" gradings: Lake Hayes, Hampden beach and the Manuherikia River, at the Shaky Bridge, in Alexandra.

All other Otago waterways have "green" gradings, including Frankton Bay; Lake Dunstan, at Alpha St, Cromwell, and at the Dunstan Arm Rowing Club, near Clyde; Lakes Wanaka and Waihola; Brighton, St Clair and St Kilda beaches; and Pounawea and Kaka Point.

 - The ORC takes samples from nominated waterways every week in summer and the results are updated every Wednesday evening on the Land, Air, Water, Aotearoa website, which also has a link on the ORC website.