Some Comments About Rangiora Water

At present we in Rangiora turn on the tap and the water comes out.  Some summers we have had to severely restrict our use in the garden, but generally we take it for granted.

OK, it turns the insides of our kettles brown.  And sometimes it smells of the chlorination that is used to kill unwanted bacteria – but, then, most water supplies around the world need to be chlorinated – Christchurch’s and Kaiapoi’s being obvious local exceptions.

So what’s wrong with it?

Rangiora’s main source of supply comes from the “Western” wells beside the Ashley River, near River Road where it meets West Belt.  There are additional wells at the Ayers Street pumping station and in Dudley Park.  These Western Wells are fed by the Ashley and are shallow.  The problems are these:

  1. Low flows in the Ashley threaten the supply of water.  As most of us know, there have been water restrictions in the past and we also know that Rangiora is growing quickly and that the demand for water will be increasing.
  2. The current chlorination kills bacteria but does not kill protozoans like giardia and cryptosperidium.  These are serious potential contaminants and the shallowness of the wells means that they are not protected.  A dead dog in the Ashley riverbed recently caused a scare.
  3. There is a risk that the draw-off of water will exceed the resource consent limits set by Environment Canterbury.
  4. The quality of the water does not meet current national standards – standards that the Council now has to meet within a few years.


The Council has looked for deep safe water in and around Rangiora on and off for twenty years.  Enough water to service Rangiora has never been found.

Further treatment to remove the risk of contamination has been found to be more expensive than the option of bringing the water from Kaiapoi – and does not get around the problem of there not being enough consentable water in the current wells.

The Council staff also looked at bringing in water from a variety of sources to the west or south.  A well drilled at Mandeville looked OK for quality but did not have the required quantity. Other wells to the west,  had the reverse problem: in combination they might have the quantity, but, being shallow, were likely to have quality problems. This was potentially the cheapest solution but there were no guarantees that the Council could get (and obtain consents for) the required quantity or meet the quality standards.

What was Planned?

Pumping the water up from Kaiapoi gets around both problems.  There is plenty there and, being deep and old water, does not need treatment.  It will not come from the same aquifer as the Kaiapoi water supply and investigations have failed to show any effect on that supply.

It will be expensive (but cheaper than treating the existing supply).  The Rangiora water rate is currently $141 per property per year.  If the planned work to source the work in Kaiapoi had been proceeded with, this would have risen to about $370 within two years.  It would have fallen back slightly after that but would have remained high mainly because of the operational costs of pumping up the slope from Kaiapoi and servicing the loans required to build the scheme.

What Are the Risks in Delaying?

The Council has been told by the staff that there are a number of risks.  These include:

  1. ongoing risk of waterborne disease
  2. increasing risk of water restrictions in summer
  3. increasing risk of a supply outage resulting from deferred maintenance on the Ayers Street headworks.

They have also been told that probable consequences are:

  1. increase in construction costs when upgrade proceeds
  2. difficulty in getting a Public Health Risk Management Plan approved (required by new legislation).

Why has the Council Delayed?

  1. Because, during the election campaign, some councillors promised not to increase rates.
  2. Because they say they want a water strategy developed before doing anything.  This seems to be about joining up existing water schemes.

There has been no indication how joining up a number of small water schemes is going to help Rangiora.  Nothing has been put into the Draft Annual Plan to pay for a physical search for other sources of water for Rangiora.

One can ask why some successful candidates campaigned on a no-rates-rise platform without apparently considering Rangiora’s water problems.

Since the 19th Century, local bodies have considered the provision of safe water a fundamental requirement.  We are now in the 21st Century.


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