Understanding soil contamination and its impact on land development

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Soil contamination occurs when hazardous substances such as heavy metals, hydrocarbons, pesticides, or other chemicals are present in the ground at levels that could harm people, plants, or the environment. Contaminated soil can affect soil health, water quality, and air quality, as well as pose risks to human health.

Because of these risks, soil contamination can have a major impact on the safety, cost, and feasibility of any land development project.

Across the Auckland, Kaipara, and Northland regions, land development is growing rapidly. As environmental standards evolve, there is an increasing requirement for contaminated land assessments as part of the planning and consent process.

At Buckton Surveyors and Planners, we assist landowners and developers by carrying out a preliminary desktop contaminated soil assessment to determine whether a full site inspection or Preliminary Site Investigation (PSI) is needed.

What causes soil contamination?

• Industrial activities: manufacturing, chemical processing, vehicle servicing and metal works.

• Agricultural practices: use of pesticides, herbicides and fertilisers.

• Fuel storage and refueling: underground tanks, service stations or depots.

• Waste disposal: landfills or areas where hazardous substances were buried or dumped.

• Urban land uses: paint residues, lead, asbestos or stormwater runoff.

Even small-scale or historical activities, such as a former orchard, market garden or workshop can leave behind contaminants that persist for decades.

Why soil contamination matters for development projects

• Pose health and safety risks during construction and for future occupants.

• Delay or halt consent approvals if not properly assessed.

• Increase costs through remediation requirements.

• Affect land valuation and marketability.

Identifying and managing contamination early in the project planning process helps mitigate environmental, legal, and financial risks, and ensures developments meet public health and environmental standards.

Regulatory guidelines and compliance: NES-CS and HAIL

In New Zealand, soil contamination is managed under the National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health (NES-CS). This national regulation ensures that land being developed or redeveloped is safe for its intended use.

A key tool used under the NES-CS is the Hazardous Activities and Industries List (HAIL), which identifies land uses that may have historically caused contamination, such as fuel storage, timber treatment or agricultural spraying.

If a property is identified as a HAIL site or suspected of contamination, a Preliminary Site Investigation (PSI) or Detailed Site Investigation (DSI) may be required. These assessments determine whether contaminants are present, their concentrations, and whether remediation or management is needed before development can proceed.

Even if you don’t suspect contamination, an assessment may still be required if you plan to:

• Subdivide industrial or production land for residential purposes.

• Change the use of land to a more sensitive activity (e.g. housing, childcare, education).

• Undertake earthworks on a site that was previously used for industrial or horticultural purposes.

How to check if contamination may exist on your land

If you suspect a HAIL activity or industry has been carried out on your property, you can:

• Ask Auckland Council (or your local council) for records they hold about the land’s use history.

• Review LIM reports, property files and regional databases.

• Seek information from previous owners or neighbours who may know the site’s history.

• Engage a Suitably Qualified and Experienced Practitioner (SQEP) to carry out a professional Preliminary Site Investigation (PSI) and assess the likelihood of contamination.

How Buckton Surveyors and Planners can help

• Identify potential HAIL activities and assess contamination likelihood using property files, LIM reports and historical aerial imagery.

• Request a Contaminated Land Information Search through Auckland Council under Regulation 6(2) of the NES-CS, covering dangerous goods, property and regional environmental records.

• Connect you with qualified environmental practitioners (SQEPs) and provide our preliminary findings to support their investigations.

• Prepare and manage any required resource consent applications.

• Coordinate with councils to ensure compliance and smooth project progress.

• Provide advice to help you plan developments that are both compliant and cost-effective.

A good starting point is the Ministry for the Environment’s publication: Information for landowners and developers. 

Whether you’re a landowner, developer or consultant, our goal is to provide clear, practical advice that ensures your project proceeds safely, efficiently, and in line with New Zealand’s environmental standards.

Contact our team at Buckton Surveyors and Planners, which is based in Warkworth, Dargaville, and Northland, to discuss your site and how we can assist with soil contamination assessments and NES-CS compliance for your next development.

Contact the team