4.15 On-site wastewater
Introduction
On-site wastewater systems are provided for residential dwellings or other facilities not served by a public wastewater network. The following rules, controls and assessment criteria apply to discharge of domestic type wastewater onto or into land and water from such sites.

Discharges of contaminants to land and water from public wastewater networks, including exfiltration, and from wastewater treatment plants are not addressed in this section.
1. Activity table
The following table specifies the activity status regulating the discharge of contaminants onto or into land and/or into water from onsite wastewater treatment systems. Refer to the zone rules for provisions regulating the use of the site for rural production activities.

[rp]
Activity  Activity status
Discharge of treated domestic-type wastewater to land within a site via a treatment and land application disposal system  P
Discharge of domestic-type wastewater to land via a treatment and land application disposal system that was a permitted activity and/or lawfully in existence without the need for a resource consent at the date this rule becoming operative  P
Discharge of domestic-type wastewater from one dwelling without permanent power supply to land within a site via a treatment and land application disposal system  P
Discharge of domestic-type wastewater to land via one or up to three treatment and land application disposal systems within a site, in circumstances where the wastewater systems cannot be feasibly combined  P
Discharges of up to 6m3 of wastewater or domestic-type wastewater not meeting the permitted activity controls  RD
The discharge of wastewater and/or trade wastes that are not provided for by any other rule in this Unitary Plan  D
The discharge of wastewater to land from a private wastewater network  D
The discharge of domestic-type wastewater by existing deep bore disposal where a replacement bore is required and there is no viable alternative land disposal option  D
The discharge of wastewater or domestic-type wastewater directly to water (unless previously authorised)  Pr
The discharge of domestic-type wastewater by new 'deep bore' disposal  Pr
2. Controls
2.1 Permitted activities
Any permitted activity that does not comply with the below controls is a discretionary activity unless otherwise stated. 
2.1.1 General
1. The wastewater discharge must not result in contamination of ground water or surface water or contaminants discharging into stormwater drains or onto neighbouring propertie.
2.The construction of the on-site wastewater treatment system and the resulting discharge of treated wastewater must not disturb any historic heritage site or any site or place of significance to Mana Whenua.
3. The wastewater treatment system must be maintained by a contracted service provider in accordance with Technical Publication 58 On-site Wastewater Systems: Design and Management Manual 2004 (TP58) recommendations, the system provider's recommendations or the suitably qualified maintenance contractor's recommendations. At a minimum, the maintenance where relevant to the specific system must ensure that:
a.treatment plant filter(s) are checked and cleaned quarterly
b.secondary/tertiary treatment plant is serviced six monthly by a suitably qualified maintenance contractor
c.primary/septic tank is pumped out by a suitably qualified wastewater system service provider when sludge and scum levels occupy 50 per cent of the tank volume, and
d.records of each maintenance action must be retained and made available on the site for inspection by the council or their agents.
2.1.2 Secondary treatment domestic-type wastewater to land within a site via a treatment and land application disposal system
1. The wastewater design flow and actual flow must not be greater than 2m3 per day.
2. The proportion of site area to wastewater discharge volume must be equal to or greater than 1.5m2 per litre per day.
3. The site is not contained or described in a title issued under the Unit Titles Act 1972 or a cross-lease form of title.
4. The site investigation procedures, design, installation and operation of the on-site wastewater treatment and land application disposal system must be undertaken in accordance with TP58, and must in particular give effect to the following matters:
a. the site assessment practices to determine the system suitability (Chapter 5 of TP58). The flow allowances used to establish system design flow must be at least 120 litres/person/day for residential dwellings and the maximum estimated water use for all other activities as specified in Chapter 6 of TP58
b. septic tanks must be fitted with an outlet filter, unless the equivalent level of treatment is provided within an aerobic treatment system
c. the secondary treatment system or better design criteria and parameter ranges provided in Chapter 7 of TP58
d. the land disposal system must comprise pressure compensating dripper irrigation with an areal loading rate of up to 5mm/day depending on soil type
e. the provision and maintenance of a minimum reserve land disposal area (Chapter 5 of TP58).
2.1.3 Treated domestic-type wastewater to land via a treatment and land application disposal system that was a permitted activity and/or lawfully in existence without the need for a resource consent at the date this rule becomes operative
1. The nature of the wastewater discharge must be the same as that existing at the date the Unitary Plan becomes operative.
2. The wastewater discharge must not exceed 2m3 per day and the design flow must be no greater than that existing at the date the Unitary Plan becomes operative.
3. The wastewater treatment and land application disposal system must be maintained in accordance with its original design or better.
2.1.4 Treated domestic-type wastewater from one dwelling without permanent power supply to land within a site via a treatment and land application disposal system
1. The wastewater design flow and actual flow must not be greater than 2m³ per day.
2. The proportion of site area to wastewater discharge volume must be equal to or greater than 1.5m2 per litre per day.
3. The site must not be contained or described in a title issued under the Unit Titles Act 1972 or a cross-lease form of title.
4. The site investigation procedures, design, installation and operation of the on-site wastewater treatment and land application disposal system must be undertaken in accordance with TP58, and must in particular give effect to the following matters:
a. the site assessment practices to determine the system suitability (Chapter 5 of TP58)
b. the flow allowances used to establish system design flow, must be at least 100 litres/person/day (Chapter 6 of TP58)
c. septic tanks must be fitted with an outlet filter, unless the equivalent level of treatment is provided within an aerobic treatment system.
d. the land disposal system must comprise pressure compensating dripper irrigation or low pressure effluent distribution systems (LPED) or trenches or beds
e. the discharge quality standards to be achieved by the system (Chapter 7 of TP58)
f. the provision and maintenance of a minimum reserve land disposal area (Chapter 5 of TP58).
2.1.5 Treated domestic-type wastewater to land via one or up to three treatment and land application disposal systems within a site, in circumstances where the wastewater systems cannot be feasibly combined
1. The design flow and actual flow for each system is not greater than 3m³ per day.
2. The proportion of site area to discharge volume is equal to or greater than 3m² per litre per day for the total combined flow of the discharge.
3. There must be no less than 100 per cent reserve wastewater disposal area per system available within the site.
4. The wastewater disposal area must be fenced to prevent heavy vehicle or access to the area by stock.
5. The site investigation procedures, design, installation and operation of the on-site wastewater treatment and land application disposal system must be undertaken in accordance with TP58, and must in particular give effect to the following matters:
a. the site assessment practices to determine the system suitability (Chapter 5 of TP58)
b. the flow allowances used to establish system design flow must be at least 160 litres/person/day for residential dwellings and the maximum estimated water use for all other activities as specified in Chapter 6 of TP58
c. septic tank must be fitted with an outlet filter, unless the equivalent level of treatment is provided within an aerobic treatment system.
d. the land disposal system must comprise pressure compensating dripper irrigation or low pressure effluent distribution systems (LPED) or trenches or beds
e. the discharge quality standards to be achieved by the system (Chapter 7 of TP58).
3. Assessment - Restricted discretionary activities
3.1 Matters of discretion
1. The council will restrict its discretion to the matters below for restricted discretionary activities. 
a. the quality and design flow volume of wastewater
b. the design and performance of the wastewater treatment system
c. the design of the disposal system, the disposal method, and the rate of land application
d. the avoidance, remediation or mitigation of adverse effects on the environment arising from the design or intended operation of the wastewater treatment and disposal system
e. the provision of a suitable land application reserve area
f. an assessment of the potential impact on Mana Whenua values.
3.2 Assessment criteria
The council will consider the relevant assessment criteria below for restricted discretionary activities. 
1. The appropriateness of the proposed on-site disposal of wastewater in terms of:
a. the absence of a community, municipal or de-centralised wastewater system available to the site, or the practicality of connecting to such a system
b. the on-site wastewater treatment and discharge is of a quality and volume that:
i. is suitable for the site conditions, including proximity to surface water bodies, stormwater drains and neighboring properties
ii. avoids significant adverse effects (including cumulative effects) on surface water, groundwater quality, public health and amenity; and other potential adverse effects are remediated or mitigated.
iii. ensures that any matters relating to the potential adverse effects of the discharge from the on-site wastewater system that impact on Mana Whenua values is identified and addressed.