Rule 7 On-site sewage treatment and disposal
The discharge into or onto land of any water or contaminants other than septage, from on-site sewage treatment and disposal systems is a Permitted Activity if:
(1) the system is already in use at the time this Rule comes into force; and
(2) the discharge does not exceed 1300 litres per day (calculated as a weekly average);
(a) the discharge shall consist only of contaminants normally associated with domestic sewage;
(b) no stormwater shall be allowed to enter the system;
(c) there shall be no direct discharge from the system to groundwater, surface water, or above the soil surface; and
(d) the system shall be maintained on a regular basis.
(e) the discharge is more than 50 metres from any surface water body, farm drain, or water supply race in any catchment being managed for water supply in the Regional Freshwater Plan (see Appendix 6 of the Regional Freshwater Plan, which can be downloaded from the documents sidebar at the right of this screen); and
(f) the discharge is more than 20 metres from any surface water body, farm drain, water supply race, or the coastal marine area in all other areas.
(3) the system is a new or upgraded system; and
(4) the discharge does not exceed 1300 litres per day (calculated as a weekly average); and
(5) the system shall be installed on the same property as the premises to which the system is connected; and
(6) there shall be no direct discharge above the soil surface;
provided that conditions (a)-(f) above and the following conditions are complied with:
(g) a site investigation shall be carried out. The matters to be addressed in a site investigation are set out in Appendix 5 of this Plan (which can be downloaded from the documents sidebar at the right of this screen);
(h) the system shall be designed, constructed and operated to meet the following performance criteria:
(i) the system shall be designed with sufficient effluent retention time to enable adequate treatment in relation to any constraints identified in the site investigation;
(ii) the effluent shall be evenly distributed to the entire filtration surface of the disposal field;
(iii) the bottom of the effluent disposal system shall be sufficiently above the groundwater at its highest level, in relation to any constraints identified in the site investigation, to prevent any contamination of groundwater;
(iv) the area available for treatment shall be appropriate for the volume of the discharge and any constraints identified in the site investigation.
The Council will accept as compliance with criteria (h)(i)-(iv) an effluent treatment and disposal system designed, constructed, and operated in accordance with the principles and procedures outlined in [Guidelines for on-sewage systems in the Wellington region WRC/RP-G-00/47]. These guidelines can be downloaded from the documents sidebar at the right of this screen.
The wording in square brackets was substituted for the original wording by Plan change 1 to the Regional Plan for Discharges to Land, 2003.
Explanation. Rule 7 applies to discharges from on-site sewage treatment and disposal systems. These include septic tank/effluent disposal field systems, evapotranspiration systems, and community systems serving a number of houses. The on-site systems may be new (i.e., constructed after this Plan becomes operative) or existing systems, and may serve dwellings, institutions, workplaces, or clusters of dwellings, so long as the daily discharge volume is less than 1300 litres. This is equivalent to the amount of effluent produced by a large household.
This rule does not apply to septage (solid materials collected from septic tanks), or the compost from a composting toilet when discharged to land, or to systems designed to discharge above the soil surface (e.g., where effluent is used for irrigation) or to systems which are located on a separate legal property to that on which the premises creating the discharge. These activities are addressed by Rules 6, and 8.
The conditions relate to "good practice". The specific maintenance requirements which comprise "good practice" will vary depending on the type of system used and the volume and quality of effluent produced. All such requirements should be made available by the manufacturer or designer of the system at the time of installation. For example, regular desludging will be necessary to ensure that the system does not overflow.
New and upgraded systems (new systems are those installed after the date on which this plan became operative, and upgraded systems are those which were installed and in use before the Plan became operative, and subsequently require improvement to avoid, remedy or mitigate any adverse environmental effects being caused by the system) must also comply with the specified design criteria and be designed to reflect any constraints identified in the site investigation. Systems designed and installed in accordance with the principles and procedures outlined in the specified guidelines, are deemed to comply with these design criteria.