Discharge to land standard
These standards come into effect on 19 December 2025. We will continue to develop material to support implementation of the standards and will keep this page updated.
The discharge to land standard provides a framework to check if land is suitable for receiving treated wastewater and then sets discharge limits based on the specific risks at that site.
The most important contaminants for discharges to land – Total Phosphorus, Total Nitrogen and E. coli – are covered by the standard.
The standard has three steps to follow.
-
Assess the risks to classify the site.
-
Check the contaminant limits and what monitoring and reporting is needed.
-
Include and implement the requirements in the resource consent conditions.
Wastewater standards are implemented by consenting authorities as conditions of consent when new or renewed wastewater resource consents are granted.
Where a regional plan enables discharges of treated wastewater to land, a consenting authority cannot grant a resource consent that imposes requirements that are different from those in the standards. This includes treatment limits for key contaminants, as well as monitoring and reporting requirements. Where a consent is approved, it must be issued for a 35-year duration.
Consenting authorities maintain discretion over matters not covered by the standards, e.g. locally significant contaminants.
View the information about timeframes for transitioning to the new standards.
We are working with the New Zealand Land Treatment Collective (NZLTC) to develop practical guidance to support implementation of the discharge to land standard. Please email stormwater_wastewater@taumataarowai.govt.nz if you wish to be notified when new guidance materials are made available.
Guidance materials will cover the following matters.
-
An overview of processes to carry out baseline and site-specific assessments to determine land suitability, considering factors such as soil type, drainage, slope, groundwater and land use.
-
How to develop and apply a risk-based framework to assign land classes and set appropriate discharge limits for Total Nitrogen, Total Phosphorus and pathogens (e.g. E. coli).
-
Guidance on assessing compliance with the requirements of the standard.
-
Guidance on developing management plans and operations manuals including monitoring, reporting and contingency planning.
Applicability and exceptions
Standards only apply to public networks, which are primarily owned and operated by local councils. They do not apply to:
-
privately-owned wastewater treatment networks or septic tanks
-
discharges from wastewater treatment plants that fall within the scope of the Australian/New Zealand Standard AS/NZS 1547:2012 (e.g. campground wastewater systems)
-
where inconsistencies have been identified with aspects of legislated treaty settlement obligations in the Waikato-Waipā, Whanganui and Whangaehu river catchments.
The discharge to land standard does not apply to wastewater that comes only from trade and industrial waste streams, or if the discharge:
-
could harm cultural sites (e.g. historic pā sites)
-
leaks from oxidation ponds
-
is applied to crops for human consumption
-
happens on unsuitable land (as determined by the site suitability assessment)
-
involves bypasses.
In these cases, an exception applies. Any proposal for discharge to land will be assessed under the existing framework by the consenting authority.
A three-step approach is used to analyse whether a specific site is appropriate for discharging treated wastewater to.
|
|
Step 1 |
Step 2 |
Step 3 |
|
Action |
Baseline assessment (not part of the standard). |
Assess public health, environmental and social risks.
|
Assess the ability of the site to receive treated wastewater. |
|
Considerations |
Includes examining geology and nearby groundwater, topography and size, and current or proposed land uses for the site. |
Any risks to groundwater, recreation areas, food growing areas etc posed by discharging treated wastewater to the site. |
In-depth analysis of the characteristics of the land (via groundwater and soil assessments), how treated wastewater would be applied, and options for reducing any potential impacts of applying treated wastewater. |
|
Objective |
Confirm whether a site is appropriate to progress to more detailed assessments in next steps. |
Determine the risk category for the site. There are four possible categories. |
Determine the ‘site capability’ category. There are four possible categories. |
Once the three steps are completed, use the table below to identify the site's classification by locating the cell that matches its risk level and site capability category.
Contaminant limits
The standard covers the most common contaminants that could have an impact on land: Total Nitrogen, Total Phosphorous and E. coli.
For the contaminants covered by this standard, regional councils cannot impose stricter or more lenient treatment requirements in resource consents.
Some contaminants, like per- and polyfluoroalkyl substances (PFAS) or heavy metals such as iron and aluminium, are not included in the standard. These may be less common or there is currently a lack sufficient evidence to set national limits. In such cases, consent authorities can continue to set treatment requirements as needed.
Different limits apply depending on the rate of wastewater infiltration to land.
-
Rapid infiltration schemes: this refers to the discharge of treated wastewater at a rate that results in an annual hydraulic load of six metres or more.
-
Slow rate infiltration: These schemes discharge at a rate resulting in an annual hydraulic load of less than six metres.
The following limits apply to slow rate infiltration schemes.
|
|
Total Nitrogen |
Total Phosphorous |
E. coli (annual 90th percentile) |
|
Class of land |
Kilograms that can be discharged per hectare each year (kg/ha/year) |
Kilograms that can be discharged per hectare each year (kg/ha/year) |
cfu*/100 millilitres |
|
1 |
550 |
110 |
No limit |
|
2 |
250 |
50 |
2,000 |
|
3 |
150 |
30 |
1,000 |
The following limits apply to rapid infiltration schemes.
|
|
Total Nitrogen |
Total Phosphorous |
E. coli (annual 90th percentile) |
|
Class of land |
Kilograms that can be discharged per hectare each year (kg/ha/year) |
Kilograms that can be discharged per hectare each year (kg/ha/year) |
cfu*/100 millilitres |
|
1 |
20,000 |
7,000 |
100,000 |
|
2 |
10,000 |
3,000 |
10,000 |
|
3 |
4,000 |
1,000 |
1,000 |
*cfu = ‘colony forming unit’. It estimates the number of bacteria that have the potential to reproduce and increase overall levels of bacteria that could make people sick. Different limits for E. Coli apply to slow rate infiltration sites where the risk of exposure is higher.
Nitrogen and phosphorus are nutrients that help plants grow. If levels of these nutrients in discharges to land are too high, they can have adverse impacts on nearby waterbodies – e.g. increasing plant and/or algae growth, and over time reducing water clarity and oxygen levels. This lack of oxygen can reduce the numbers of aquatic animals (e.g. shellfish and other invertebrates as well as fish). Nitrogen and phosphorous can be measured in different ways. The standard sets limits for ‘Total Nitrogen’ and ‘Total Phosphorus’ which includes all forms of nitrogen and phosphorous in treated wastewater. This makes measurement consistent and straightforward.
E. coli is a type of bacteria commonly found in the intestines of warm-blooded animals including humans. They’re a useful indicator of whether bacteria, viruses or protozoa (single-celled parasites, like cryptosporidium and giardia) that can make people sick are present in soil and freshwater.
Management and operation plans
As part of this standard, all sites that discharge to land would be required to develop both a management plan and an operations and maintenance plan.
These will include:
-
operations and maintenance procedures (e.g. when discharges can take place, how often inspections are required or desludging schedule)
-
risk management planning
-
environmental monitoring requirements.
Please email stormwater_wastewater@taumataarowai.govt.nz if you wish to be notified when guidance material on management and operation plans is made available.
Monitoring and reporting requirements
As part of this standard, all sites that discharge to land are required to implement some minimum monitoring and reporting requirements. These include:
- monitoring of treated wastewater
- groundwater monitoring
- regular reporting to regional councils and the Water Services Authority – Taumata Arowai
- published on a publicly accessible website.
The full suite of monitoring and reporting requirements will be set by the relevant consenting authority.