This warning came yesterday from the Waitaki District Council's assets committee chairman, Cr Alistair Mavor, who is writing to Waitaki MP Jacqui Dean seeking answers from the Government and ministry.
The council is spending $4.6 million over six years upgrading its 21 water schemes to meet new drinking water standards.
However, Cr Mavor's concern at yesterday's council meeting was not the cost of upgrading, but the ongoing annual cost of regular tests under the new standards.
In particular, he is worried about the impact on small schemes opting for "point of entry" treatment - individual water treatment, such as ultraviolet and filters, at the house rather than where the water enters the scheme.
"Point of entry", particularly on smaller schemes, is cheaper than building or upgrading a treatment plant.
Cr Mavor had no issue with upgrading to meet standards, but "the cost of that [testing] will be a real threat to the ability of some of our smaller schemes to survive," he said.
Council testing assessors Public Health South indicated a visual inspection of each household's point of entry treatment would be needed, preferably daily, or at least weekly.
That would cost each household getting 1800 litres a day $420 a year.
"This makes a very expensive water supply and effectively rules out this treatment option [point of entry] for the majority of council's smaller supplies," he said.
Some water scheme committees had told the council they did not see a need to treat all the water entering their schemes when much was used for stock and other farm uses.
Point of entry treatment at the house was a logical and practical alternative.
Farmers may change to irrigation schemes to supply stock water and for other uses, reducing demand on the water schemes and threatening scheme financial viability.
Cr Mavor wants Mrs Dean to provide details on the likely level of testing required, when the testing rules would be confirmed and when the Government subsidy scheme for upgrading water supplies would be reopened.
