Three Waters Practice Notes – on-lot stormwater management
What is stormwater and three waters?
When land is developed, rainwater flows differently across the site. This can increase flooding, affect waterways, or cause problems for neighbours if it is not managed properly.
These Practice Notes explain how stormwater needs to be managed on your own property (called on lot stormwater management) and help with achieving compliance with the stormwater requirements of the Hamilton City Council (Council) District Plan when you are building or developing in Hamilton. Some also include information about water supply and wastewater, not just stormwater (combined they are called the three waters).
Why does stormwater need to be managed?
Stormwater from roofs, driveways, and other hard surfaces can:
- Increase flooding on your property and nearby land
- Carry sediment and pollutants into streams and rivers
- Cause nuisance or damage to neighbouring properties
Managing stormwater properly helps to:
- Reduce flood risk
- Protect the environment and restore the mauri of the Waikato Awa
- Keep our neighbourhoods safe and healthy
Hamilton City Council is also required to meet regional and national environmental rules, including Waikato Regional Council’s Comprehensive Stormwater Discharge Consent.
Who is responsible?
Stormwater management is a shared responsibility:
- Hamilton City Council manages the wider public stormwater network and must meet regional and national requirements. They also undertake high-level inspections of on-lot devices to meet the requirements of the Comprehensive Stormwater Discharge Consent.
- Property owners and developers are generally responsible for managing stormwater on their own site, in line with the District Plan and technical requirements.
What are the Practice Notes?
The Three Waters Practice Notes are guidance documents that explain:
- What the District Plan, Regional Infrastructure Technical Specifications, and Stormwater Bylaw 2021 requires.
- How stormwater can be managed on-site.
- What information may be needed as part of a development or building application.
They are designed to help you understand your obligations and get it right the first time. Using these Practice Notes can help you:
- Understand what Hamilton City Council expects before you apply
- Avoid delays, redesigns, or extra costs
- Reduce the risk of flooding or issues on your property
- Protect waterways and neighbouring properties
For homeowners, this usually means clearer requirements and fewer surprises during the build or development process.
What do the Practice Notes cover?
On this page you will find:
- Guidance on designing common on lot stormwater management devices.
- Guidance about what information needs to be included if the District Plan requires you to provide:
- A Site Specific Stormwater Management Plan (how stormwater will be managed on a particular site)
- A Three Waters Infrastructure Capacity Assessment (evaluation of whether existing three waters infrastructure can accommodate a proposed development)
- A Water Impact Assessment (the combined effects of a development on drinking water, wastewater, and stormwater)
- An Integrated Catchment Management Plan (a high-level planning document that sets out how the three waters will be managed across the entire catchment or sub-catchment).
- Information for specific developments (e.g. industrial/commercial sites)
Where do I start?
Start with reading the HCC01 Overview Practice Note which outlines requirements and next steps. The form below is also a helpful tool for understanding what may be required for your site.
Many projects will need input from a designer, engineer, or planner, especially for larger or more complex developments.
These Practice Notes are not a substitute for professional advice, but they explain what is required and why.
We recommend contacting Hamilton City Council early in your project if you have queries about any aspect or to confirm what is required for your site.
Email: info@hcc.govt.nz
Ongoing requirements for owners
Property owners are responsible for the ongoing maintenance of on-lot stormwater management devices on their property. This is to ensure the devices continue to function as designed and do not contribute to flooding, nuisance, or environmental harm.
Please refer to the brochures below for helpful information on how to maintain your device. These also include information on common issues you may face with your device, and how these can be fixed.
Your device may be inspected and audited by Hamilton City Council as part of compliance requirements. You will be contacted prior to your device being audited.
Practice notes
Practice-Notes
Standard-Drawings
Maintenance Brochures for Residential Devices
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Last updated 1 July 2026