Septic tank system flush with success

Last Updated : 15 Feb 2022
System (1)

A collection of 45,000 septic tanks wouldn’t usually trigger excitement, but for Lizzie Johnson it was like winning Lotto.

It’s been known for some time septic tanks were contaminating waterways and streams across Auckland, but there was no efficient way to monitor the systems.

It took a massive effort to identify them and develop a compliance system to ensure septic tanks are regularly inspected and maintained.

Launched in November last year, the onsite wastewater compliance system is the first local government system of its kind in New Zealand.

“This system will have a huge impact on our beaches and streams and on people’s health,” says Senior Healthy Waters Specialist, Lizzie Johnson.

“It gives us more confidence septic tanks are being properly maintained and if they don’t meet safety standards, we can act more quickly to ensure they’re fixed.”

The challenge

Most properties in Auckland are connected to Watercare's piped network and pay for wastewater. But households that are not connected have private septic tanks to treat sewage and other wastewater.

Under the Auckland Unitary Plan, owners of these properties must provide regular inspection records verifying their onsite wastewater systems are in good working condition.

Previously there was no consistent information on the type, condition and maintenance history of septic tanks being used. To accurately capture this data, all septic tanks across the region – from Franklin to Rodney and on Waiheke, Great Barrier and Kawau islands needed to be located. It took Healthy Waters and Proactive Compliance teams two years to identify all the households using septic tanks; data for 45,000 properties was eventually collected and migrated into the new system, along with 9000 supporting documents.

The search involved:

  • Using GIS mapping system to identify areas and properties not connected to Watercare’s main wastewater network
  • Reviewing building and resource consents
  • Searching emails, and manual records and notes
  • Contacting property owners by mail and visiting properties in high-risk catchment areas to request information about their maintenance records.

Second phase goes live

An app-based form to make it easier to record new data from external contractors who clean and inspect septic tanks for property owners has also been developed. Information from contractors using the app will automatically update the corresponding property file in the compliance system.

Auckland Council's Proactive Compliance team will now start requesting and processing more maintenance records and create reports to identify overdue and failed inspections.

“The health of our waterways is vital to Auckland’s future,” Lizzie says. “By giving us accurate and consistent information within hours of an inspection, this system will go a long way to help us reduce public health risks from wastewater and improve our water quality.”

Onsite wastewater system compliance is one of five programmes funded by the water quality targeted rate, which aims to make our harbours, beaches and streams cleaner. Another programme is the western isthmus water quality improvement project, which is reducing wastewater overflows into the Waitematā Harbour and stormwater into the wastewater network.

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