Fears have been building water pooling in the quarry on the Old West Coast Road could be leaching into Christchurch's water supplies.
The quarry had the final sign-off in May last year - meeting all the conditions of the consent in regard to the rehabilitation of the site.
But after ongoing issues with the land - ECan and residents requested testing of the site carried out by Hill Laboratories.
Both sets of samplings provided to the NZ Herald show different results.
Residents received results showing E. coli in the water is 25 times above the acceptable level.
The maximum acceptable value level is less than one.
But ECan's central zone manager Joannes Welsch said from the results they received - their groundwater science team has no concerns over the water quality at the quarry.
Lucy Hogan, the landowner of the rehabilitated property, said Hills Laboratories have done their job properly but clearly were asked to do two different types of tests.
Welsch said ECan wants to consider all relevant evidence relating to this investigation - but residents have not passed on their results.
He said it did not have access to the E. coli results as the laboratory was unable to test in the required time period.
Previous investigations show E. coli detected is as likely to come from neighbouring properties as from the quarries, Welsch said.
Long-time Yaldhurst resident Anna Youngman disagrees with ECan's findings and believes the next step may be a judicial review.
She said there is no denying the water is contaminated and ECan needs to take action.
"It is just ridiculous in what they are saying. With all this glass and rubbish still surfacing, the water is still ponding and it's toxic water."
Concerns are mounting the rehabilitated quarry will never be used for productive farming land again.
But Welsch said their investigations shows stored topsoil at the quarry site was used to rehabilitate as per the consent requirement - and soil levels are not of concern.
Living on the land - which was signed off by authorities as good farmland - has proved to be an endless headache for Hogan.
When she first viewed the land - it appeared perfectly fine and has the photographs to prove it.
She said to later find out after purchasing the land that it is so toxic, she cannot take her dog walking in it nor have stock - is upsetting.
As a precaution, Hogan has now had her water bore tested and is awaiting results.