Do I need a Resource Consent for my Septic Tank?

Resource Consent or Permitted Activity? Installing or upgrading a septic tank or on-site wastewater system can seem straightforward but under the Resource Management Act 1991 (RMA), any discharge of contaminants to land or water requires either:

• Explicit permission under a regional or unitary plan (Permitted Activity), or
• A Resource Consent from the relevant council.

Because wastewater discharges have the potential to affect water quality, soil health and ecosystems, every regional council (and the six unitary authorities) sets its own rules and thresholds.

Although the details vary between councils, several common national triggers determine when a system moves from “permitted” to “consented”.

Proposed National Wastewater Regulations

The proposed national wastewater environmental performance standards, currently being developed by Taumata Arowai, aim to set consistent national rules for public wastewater networks but do not apply to privately owned on-site systems such as domestic septic tanks.

This means the triggers for when a septic tank requires a resource consent remain unchanged and continue to be governed by each regional or unitary council’s local rules, though future updates may eventually extend national standards to include on-site systems.

Common National Thresholds for Requiring Consent

These thresholds align with NZS 1547:2012 (On-site Domestic Wastewater Management)the design standard most councils refer to when assessing systems.

Why Location and Rules Matter

While the 2 m³/day and setback rules are common, each regional or unitary authority sets local variations based on:

• Topography and soil permeability (e.g., clay vs sand)
• Proximity to sensitive receiving environments (streams, estuaries, wetlands)
• Groundwater vulnerability
• Local drinking-water supplies and aquifers
• Type of development (residential vs tourist, subdivision, commercial)

For example:

• Auckland Council (Unitary Authority) applies the E5 rules of the Auckland Unitary Plan, with stricter standards in coastal and island areas.
• Bay of Plenty Regional Council and Waikato Regional Council have almost identical 2 m³/day thresholds, but apply higher treatment expectations near Lake Rotorua or the Waikato River.
• Tasman, Marlborough and Nelson apply similar thresholds but link them to catchment sensitivity under their combined regional/district plans.

Advanced Systems and Disinfection (UV or Chlorine)

When sites are near water, in high-risk soils, or use spray irrigation or dripper dispersal, councils often require secondary or tertiary treatment with disinfection, commonly UV or chlorination to remove pathogens.

However, there is no national blanket rule:

• Some regions (e.g., parts of Auckland’s islands or coastal zones) strongly encourage disinfection;
• Others only require it for spray irrigation or consented systems exceeding basic thresholds.

Whether disinfection is required depends on:

• Consent conditions for the site,
• Disposal method (e.g., spray = disinfected secondary effluent), and
• Proximity to people, water and sensitive habitats.

Key Takeaways for Homeowners and Developers

1. Check your region’s plan. Look under the regional or unitary council’s “on-site wastewater” rules (often called “E5” or “DW1”).
2. Confirm your discharge volume, setbacks and site sensitivity.
3. Engage a suitably qualified wastewater designer early they can model flows, soil loading and determine if your system can stay “permitted.”
4. If you need consent, expect conditions for:
   • regular servicing (3-yearly for primary, 6-monthly for secondary),
   • maintaining records and, if required,
   • flow monitoring, sampling or disinfection performance reporting.

In Summary

While every council applies local nuances, most follow the same broad pattern:

If your system discharges ≤ 2 m³/day to land, outside a sensitive area, meeting all setbacks and maintenance standards, it’s usually permitted. If not, a resource consent is required.

Understanding these triggers early helps you design a compliant, sustainable wastewater system and avoid costly delays later.

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