Accessibility quick skip links

Dunsandel Community Water Supply Contamination

Current location in the site

Update 25th August 2011

Water quality testing continues on a weekly basis.  As there has been no contamination recorded since April 2010 we will only update this site if there is a contaminated reading.

If you have any queries or concerns please contact the Council.

Previous Updates

29th November 2010

17th June 2010

4th June 2010


29 November 2010 Letter to residents.

Update from Public Meeting 17th June.

There was some excellent debate at the public meeting of 17 June, and some interesting points raised. We would like to thank those from ECan and the District Health Board that came to share their expertise.

It is a frustrating situation for both the Council and the community alike. Council staff are very clear that providing safe to drink water is a priority. We have achieved this with an ultra-violet (UV) light system now killing any bacteria that may be in the well (source) water.

The water we provide to your property is safe to drink. The water has been treated since October with chlorine and now more recently UV light treatment. Water does NOT need to be boiled before using.

The tests we take show bacteria are present before the UV treatment. We continue to take these tests before the treatment and in the townships pipe network, which confirm a safe to drink supply.

What is bacteria type - DNA testing

We know that the bacteria are from ruminants. Only days before, Council had been approached by a specialist in the North Island who claims that they have the techniques available to determine the type of animal. The scientist has been contacted and asked to provide further details. We are not about to undertake DNA testing if the potential for uncertainty is there. We will update you via the website as further details come to hand.

We will revisit the cost of inspecting the well casing (inside of casing) shortly and get a more precise figure. We will also get a quoted price for tracer testing to be put down the outside of the well casing to see if these turn up in our well.

Thank you to those that have pointed us in the direction of some potentially contaminated wells in the area. We have been in contact with ECan this morning to check this information in terms of well depth and location. It may be possible for ECan/SDC to do another round of sampling of some close wells at approximately the same depth to check the wide spread effect. We will keep you up to date with any new information.

Of course the main issue raised many times at this meeting is 'Who pays?' The Public Health Risk Management Plan (PHRMP) is the Dunsandel ratepayers chance to tell the Council what they want done with the water supply and how this should be funded. Please make sure you get your feedback to the locked box at the Dunsandel Store or Council Headquarters at Rolleston, or email

Both your Regional and District Council continue to investigate and research the contamination issue. Any information and feedback is always welcome. 

Update 4 June 2010

Water Contamination - Type of Bacteria

It is clear from the testing done to date that ruminants, including cows, are the sole cause of the bacteria in the water supply. We have no evidence that suggests onsite septic tanks are the cause. There is no current ability to confirm exactly where the contamination has come from. Quite simply the area around the site is farmed, and there are potentially many "pathways" from the ground surface activities to groundwater. Council staff continue to be involved in a large number of projects all centred on trying to identify the route of bacteria. 

Water Quality Testing

Water testing is being done once per week at present. Supported by the Ministry of Health, this testing programme has not detected any bacteria in the well water since early April 2010. Previous test results 

The Ultra Violet Water Treatment System Is Now Working

The water remains safe to drink.

From the week of 3 May 2010, the refurbished Ultra Violet light system has been working to kill bugs that might be in the well water. The chlorine dosing system has been turned off as a result, but the chlorine taste may take several more days to disappear.

What is Council Doing Now?

Council staff continue to be involved in a large number of jobs all centred on helping to identify the probable cause of the bacteria into the well water.

1. Working with ECan to share water quality, water take and age testing information

2. Provision of a draft Public Health Risk Management Plan (PHRMP) to the Dunsandel Township Committee for their discussion - meeting 17 June 7pm at Dunsandel Hall. Representatives from Environment Canterbury and the District Health Board will be attending the meeting to answer questions. Copies of the full document can be obtained from the Council or at the Dunsandel Store or on the link above. A summary of the document will be posted to residents. Feedback can be returned to the box at the Dunsandel Store or the Council or email to by 25 June 2010.

Through this document and resulting community consultation the long term options will again be reviewed. 

We also continue to respond to many queries from media, the township committee, Councillors and ECan.



Footer navigation list

© Selwyn District Council | Edit |