Cause of water contamination found

Following reports over the past week about kerosene or diesel tasting water around the Upper Riccarton area, Council staff have found traces of fuel at the top of a well at a water pumping station in the area.

Operations and Maintenance Manager Mike Bourke says that a small leak has been found in an underground diesel fuel line at the pumping station.

“The location of this leak is close to the well, although just how this diesel fuel migrated to the well has not been determined. It is very likely that a small quantity of the leaked fuel was sucked into the top of the well and tainted the water supply, and that this is the sole cause of the contamination that occurred last Friday night and over the weekend.“

Preliminary results from the samples taken over the weekend from a number of streets where the odour and smell appeared to be the strongest have shown minute traces of a petroleum product. Mr Bourke says that while the samples did smell, these results also showed that the water was well within the Ministry of Health Drinking Water 2000 Standards. “Unfortunately it takes only a small amount of petroleum product to taint a very large volume of water.”

Further samples of the water have been sent away for analysis, to confirm that the source of the contamination was from the fuel leak at the pumping station. Staff are currently determining how the fuel got into the wellhead and are making the necessary repairs at the station. Full testing will be carried out before the station is returned to service.

Mr Bourke says that the extensive flushing carried out at the time seems to have resolved the issue, since no further complaints have been received since Monday. A total of 35 households were affected.

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