Stormwater and your property

Discharging swimming pool and spa pool water

Certain conditions must be met when discharging water from a swimming pool or spa pool to stormwater, a river, water course or ground as discharged water may contain traces of chlorine or other chemicals at levels which could be harmful to the environment or toxic to fish.

Permission is not required to discharge domestic swimming pool or spa pool water into the wastewater (sewer) system in Christchurch.

Canterbury Land and Water Regional Plan

The Canterbury Land and Water Regional Plan includes the following rules for the discharge of swimming pool and spa pool water:

5.10 The discharge of swimming pool or spa pool water into water or onto or into land in circumstances where a contaminant may enter water is a permitted activity, provided the following conditions are met:

1. The discharge of filter backwash water is only onto land, and the discharge does not enter any surface waterbody or wetland, including via a stormwater system; and
2. For swimming pool or spa pool water discharges that do not contain filter backwash water, the discharge may be either onto land or into water, provided:
   (a) that for all discharges:
             (i) there are no copper chemicals or flocculants, including aluminium salts, in the discharge and the concentration of sodium chloride (common salt) does not exceed 3500 g/m³; and
             (ii) the swimming pool or spa pool has not been treated within the previous 14 days with a pool sanitizing agent containing chlorine, bromine, or Baquacil^TM; and
             (iii) the discharge does not result in water or contaminants flowing onto another site; and
   (b) that for discharges to surface water:
             (i) the discharge is not within a Group or Community Drinking-water Protection Zone as set out in Schedule 1; and
             (ii) for discharges to a river, the rate of flow in the river, at the point of discharge, is at least five times the rate of discharge.

5.11 The discharge of swimming pool or spa pool water into water or onto or into land in circumstances where a contaminant may enter water that does not meet one or more of the conditions of Rule 5.10 is a restricted discretionary activity

The exercise of discretion is restricted to the following matter:

1. The actual and potential environmental effects of not meeting the condition or conditions of Rule 5.10.

If the discharge of swimming pool or spa pool water is a restricted discretionary activity under Rule 5.11, then a consent from Environment Canterbury will need to be obtained. For further information, or if you suspect someone of emptying their swimming or spa pool into the stormwater system that does not meet with the conditions please contact Environment Canterbury(external link) (ECan).

These items must not be put in any wheelie bins. Some items are accepted at EcoDrop(external link) recycling centres, preferably in the original container or in a labelled container:

• liquid chemicals
• dry chemicals
• household cleaners
• used car oil and automotive liquids
• car batteries
• paints and associated painting solvents
• refrigerators and freezers
• gas cylinders
• fire extinguishers
• garden pesticides
• cooking oil.

Please see the hazardous waste and household chemicals webpage for more information.

Stormwater attenuation minimises the effects of increased runoff from small sites in Christchurch. 

Why do we need to reduce stormwater runoff

On undeveloped land, a large proportion of rain soaks into the ground and either flows slowly through the upper soil layers into streams or seeps down into groundwater, as illustrated in the diagram below. Development results in increased impervious (hard) surfaces that have a number of negative effects on stormwater:

Before development                After development

• The volume of runoff is increased as less water soaks into the ground (think of what happens to rain on a roof as opposed to a grass surface).
• The speed at which runoff reaches a stream increases, resulting in changed flows in the stream.
• There are increased flows in streams that increase erosion and affect habitats.
• Flooding becomes more common due to the increased volume of runoff and the speed with which it reaches pipes and waterways.
• Pollutants are more easily washed off from hard surfaces and affect stream water quality.

Even small sites can have a negative effect on stormwater, and when this is combined with hundreds of other small sites the effect can be significant. It is therefore important to mitigate these effects to help clean up Christchurch’s streams and to reduce flooding. The measures described can also be used by anyone wishing to develop their property in a more sustainable way. Reducing runoff helps to recreate the way that rain behaves on undeveloped land. This can be achieved, in order of preference, by:

1. Reducing the amount of runoff generated within the site by minimising the impervious surfaces.
2. Increasing the amount of water soaking into soil, such as through soakage systems, permeable pavement, or rain gardens.
3. Holding back as much of the runoff as possible using a stormwater storage system and releasing it slowly.

The acceptable solutions for minimising the effects of increased runoff from small sites in Christchurch are below.

Situations covered by these solutions

These solutions are applicable for development on small (less than 1000 m²) residential or commercial sites. However, not all development on small sites requires runoff to be reduced. The criteria below are used by Council to determine whether or not a site requires mitigation.

Developers of existing sites where the coverage is already greater than 70% of the total site area will need to discuss attenuation requirements with the Council.

These guidelines are about how to reduce the peak flow from your roof, driveway and hardstanding areas.

Stormwater tank installation guidelines [PDF, 381 KB] [PDF 381KB]

Under Section 30 of the Water Supply and Wastewater Bylaw 2022, prior written approval is needed from the Council to discharge stormwater into and/or to connect to the Council's stormwater network. This includes but is not limited to: kerb connections, pipes or outfalls into waterways or open drains.

Conditions of connecting

We may impose conditions of connecting to the network based on the requirements of an operative Stormwater Management Plan or a stormwater network discharge consent, which the Council holds from Environment Canterbury. Conditions could include providing onsite rainwater storage to avoid increasing flooding downstream, or a treatment system to remove contaminants from stormwater.

Consent

If you are planning a building or development that would use our stormwater network we suggest you get advice early on to take this into account in the design and consenting process. Please contact us at stormwater.approvals@ccc.govt.nz with a description of your proposal.

Before construction commences, Council engineering acceptance must be obtained for stormwater works outside the property boundary if the pipe is 225 millimetres diameter or greater. The drawings will be checked to ensure they comply with the Council's Infrastructure Design Standards (IDS), Construction Standard Specifications (CSS) and any other relevant standards and guidelines, then stamped and signed by a Council officer. More information about this can be found on the engineering plan acceptance for three waters infrastructure web page.

In addition to the permission to connect to the Council stormwater network, we also require stormwater discharge compliance with Environment Canterbury’s regional rules. We hold a number of discharge consents throughout the district, which we may use to authorise the discharge of stormwater into our network. Compliance with relevant consent conditions may require onsite stormwater mitigation (treatment and/or attenuation/disposal). Before a building consent can be issued you must seek authorisation from the Council’s Three Waters and Waste Unit by contacting stormwater.approvals@ccc.govt.nz.

If we do not authorise the stormwater discharge under one of our global consents, separate authorisation from Environment Canterbury may be required prior to a building consent being issued. The obtained authorisation must be included with the supporting documents of your building consent application.

This is a separate process to the Building Consent process. Even if your building consent plans are approved, this does not constitute permission to connect or discharge into the Council's stormwater network.

If you are rebuilding a house or garage you must check your plans don’t involve building over a Council drain.

The Council's Water Supply and Wastewater Bylaw 2022 specifies the proximity of building work near drains – including public water, wastewater and stormwater pipes. This is so the Council can check, repair and replace drains quickly and efficiently. For more information please see the building over pipes page(external link).

Use our interactive map to see public utility pipelines and waterways.

Even small sites can have a negative effect on stormwater, and the cumulative effects of hundreds of other small sites can be significant. It is therefore important to mitigate these effects to help reduce flooding and contaminants in stormwater.

Find out more in the onsite stormwater mitigation guide [PDF, 1.6 MB].