Two people charged in relation to dumping oil drums on Auckland roadsides face up to two years in jail if convicted.
Thirty charges have been brought by Auckland Council against two individuals and a company under the Resource Management Act.
It is the first time the council has prosecuted an incident of roadside dumping under the RMA which requires a discharge of contaminants into the environment to have occurred.
Sixteen charges relate to two incidents in the Waitākere Ranges in January and March, six are for a similar incident in Manurewa in December and eight relate to the storage of oil barrels at the home and business addresses of one of the defendants.
"The oil spewing out of the oil filters from the barrels, that is a contaminant, and made worse by in the Waitakeres they were dumped above a reservoir that feeds into Auckland's water supply," Mayor Phil Goff told the Herald.
"We have brought the most serious offence with the most severe penalties."
As well as jail time, the act allows for maximum fines of $300,000 for an individual and $600,000 for a company.
Charges have been laid against two people and an associated company.
It is understood the investigations involved tracking labels on the drums.
The case is set to be called in the Manukau District Court tomorrow..
In the first week of this year, 28 oil drums were dumped in a car park in the Waitakere Ranges. Runoff from the drums threatened the upper Nihotupu Reservoir which supplies water to Auckland.
A second lot of oil drums were dumped in the Waitakere Ranges Regional Park in March.
Goff said he hopes the prosecution will send the message that the council will prosecute serious cases when it has sufficient evidence and that "there are serious consequences for those who dump commercial waste or domestic rubbish illegally".
"It is the first very clear results of the extra effort and investment we are putting into this.
"It was the dumping of the oil barrels that got me to the point of where I said I'd had a gutsful and that we had to do something about people who are so irresponsible as to dump this sort of product on the side of the road."
Goff vowed to beef up enforcement after coming across leaking oil drums on the side of the road in Ardmore on his drive to work early this year. That dumping is not part of the current prosecutions.
Some of these were by a commercial operator because no one has dozens of oil filters from changing the filter in their own car, the mayor said.
"We have set up the 0800 NO DUMP dedicated line so people can give information to us and so that Council can also clean up the rubbish more quickly which is now happening," Goff said.
New resources to combat dumping and speed clean ups announced in February included the 0800 number, three more enforcement staff (bringing the total to nine) and doubling the number of CCTV cameras in hotspots to 14.
Steve Pearce, Auckland Council's Manager Regulatory Compliance, said that the seriousness of the incident prompted such serious charges being laid.
"Where offences cause significant effects or the offenders are out to make money by dumping material they have been paid to dispose of properly, we will take enforcement action including prosecution."
Besides the RMA, the Litter Act 1979 provides for fines of up to $30,000 for a company and $5000 for an individual.
The council brought two prosecutions last year under the Litter Act. It also issued $20,000 in instant fines but on average manages collect less than half.
Reports of illegal dumping are up 83 per cent since the hotline was installed and 95 per cent of the dumped rubbish was being cleared within five days of the job being logged, according to council data.
About 1300 tonnes of illegally dumped rubbish is collected each year at a cost exceeding $1 million.