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Onsite Sewage Management

Some parts of Hornsby Shire do not have sewerage services and it is the responsibility of property owners to choose a method to treat wastewater.

Approval to install

Council approval is needed to install a new onsite sewage management system or upgrade your existing system.

Apply Now

There are guidelines to follow and documents you will need to submit when you are applying for an Approval to Install a Wastewater System. Please review the relevant checklist below to make sure you have all relevant information ready before you apply.

Please complete the Owner’s consent form and submit a signed copy with the application.

Download Owner's Consent Form

Checklists for Prior to Installation

Required Information for the installation of Trenches

When lodging your application, the following information must be supplied in order for Council to assess your application.

  1. Manufacturer’s plans and specifications indicating tank dimensions, capacity and brand; plus the licensed plumber’s name, address, phone number and licence number.
  2. An accurately drawn, detailed site plan drawn to scale and showing:
    1. The position of the house, including aspect.
    2. Floor plans for the dwelling showing all bedrooms, study, rumpus room, etc.
    3. The sanitary fittings of the house (including toilet(s), bathroom(s), kitchen and laundry wastewater disposal points), internal and external drainage lines leading from the dwelling to the wastewater tank(s).
    4. The position of the wastewater tank(s), ensuring at least 1.5m distance between tank/s and dwelling, property boundaries, driveways and any impervious surfaces.
    5. Location of property boundaries, watercourses, easements, bushland, recreation areas, etc. (Point 5, Page 6)
    6. A contour plan of the disposal area indicating trench position and dimensions. Note that the trench must be constructed parallel to the natural contours of the land. Trench location must comply with setbacks in accordance with AS1547:2012 OR:
      • 12 metres if up-slope and 6 metres if down-slope of property boundary
      • 6 metres if up-slope and 3 metres if down-slope of swimming pools, driveways and buildings
      • 100 metres from permanent surface waters (e.g. rivers, streams, lakes, etc)
      • 250 metres to domestic groundwater wells
      • 40 metres to other waters (e.g. farm dams, intermittent waterways and drainage channels, etc)
      • 20 metres to natural bushland
  3. Provide details on topography, soil type, soil composition and vegetation within the intended disposal area (this includes presence of rocky outcrops, slope, potential drainage problems, etc).
  4. Position of all roof, surface and subsoil drainage pipelines to their points of discharge.

Calculation to Determine Absorption Trench Length

Calculations for the required length of absorption trenches are to be made in accordance with the Australian Standard AS1547:2012. The following table contains a guide for trench length for wastewater disposal by sub-soil absorption.

LENGTH OF ABSORPTION TRENCH (METRES) FOR WASTEWATER DISPOSAL
BY SUB-SOIL ABSORPTION *

NUMBER OF
BEDROOMS
SOIL TYPE
SANDLOAMCLAY LOAMLIGHT CLAY
2 50m 66m 98m 190m
3 62m 82m 121m 240m
4 74m 98m 146m 288m
5 87m 115m 170m 330m

* A reserve area equal to the primary trench area is also to be shown on the site plan

Please Note:

  1. Failure to supply the above information may result in processing delays.
  2. Council requires that all wastewater applications are prepared in accordance with recommendations in Environment & Health Protection Guidelines - Australian Standard 1547:2012.
  3. The length referred to is in accordance with standard dimensions outlined in AS 1547:2012 and is only intended as a guide.
  4. Due to low permeability, trenches are not suited to clay soils.
  5. The position of the trenches relative to the wastewater tanks may result in the installation of a pump and secondary tank.
  6. Should you require information on tank sizes, contact the Environmental Compliance Team on 9847 6829 or compliance@hornsby.nsw.gov.au

Download Septic and Trench System Information

Required Information for the installation of Pump-out

When lodging your application, the following information must be supplied in order for Council to assess your application.

  1. Manufacturer’s plans and specifications indicating septic tank and collection well(s) dimensions and capacities, plus the licensed plumber’s name, address, phone number and licence number.
  2. An accurately drawn, detailed site plan drawn to scale and showing:
    1. The position of the house.
    2. Floor plans for the dwelling showing all bedrooms, study, rumpus room, etc.
    3. The sanitary fittings of the house (including toilet(s), bathroom(s), kitchen and laundry wastewater disposal points) with internal and external drainage to wastewater tanks marked.
    4. The position of the tanks, the draw-off pipe and the suction outlet at street level. Note that tanks must be located a minimum of 1.5m from the dwelling, driveway or any impervious surfaces.
    5. The position of the tanker standing area located a minimum of 3 metres from the centre line of the road.
    6. A contour plan from dwelling to draw-off pipe.

Please Note:

  1. Failure to supply the above information may result in processing delays.
  2. Delays in approval may occur if Council’s Environmental Compliance Team needs to assess the availability of adequate access and manoeuvrability of sullage tankers.
  3. If the holding well is installed in a position lower than the pipe outlet, a pump must be installed. This pump must be capable of delivering a flow rate of 364 L / min at the outlet.
  4. If the holding well is installed in a position higher than the pipe outlet, a gate valve must be installed at the draw off pipe.
  5. In situations where the placement of the pump-out pipe is through another property, an easement must be created. This may require assistance from solicitors and must adhere to Council’s “Terms of Easement” conditions.
  6. To determine the optimum capacity for both septic tanks and holding wells, contact the Environmental Compliance Team on 9847 6829 or compliance@hornsby.nsw.gov.au.
  7. Council requires that all wastewater applications are prepared in accordance with recommendations in Environment & Health Protection Guidelines and Australian Standard 1547:2012.

Download Septic and PumpOut Information

Required Information for the installation of an AWTS

When lodging your application, the following information must be supplied in order for Council to assess your application.

  1. Manufacturer’s plans and specifications indicating tank dimensions and capacity, plus the licensed plumber’s name, address, phone number and licence number.
  2. An accurately drawn, detailed site plan drawn to scale and showing:
    • the position of the house, including aspect
    • floor plans for the dwelling showing all bedrooms, study, rumpus room, etc
    • the sanitary fittings of the house (including toilet(s), bathroom(s), kitchen and laundry wastewater disposal points) with internal and external drainage to wastewater tank(s) marked
    • the position of the treatment tank(s), ensuring at least 1.5m distance between tank/s and dwelling, property boundaries, driveways and any impervious services
    • position of roof, surface and subsoil drainage pipelines to their point(s) of discharge

      A contour plan of the irrigation area (note that this area shall include a duplicate irrigation area and be distinct and separate from playing areas, swimming pool yards, fruit and vegetable gardens). Setbacks must comply with Australian Standard 1547:2012 or the following must be adhered to for spray irrigation:
      • 6 metres if area up-slope and 3 metres if area down-slope of driveways and property boundary
      • 15 metres to dwellings or any other building
      • 3 metres to paths and walkways
      • 6 metres from swimming pools
      • 100 metres to permanent surface waters (e.g. rivers, streams, lakes, etc)
      • 250 metres to domestic groundwater well
      • 40 metres to other waters (e.g. farm dams, intermittent waterway, drainage channels, etc)
      • 20 metres from natural bushland

      For surface drip and trickle, or sub-surface irrigation systems, the following setbacks must be adhered to:

      • 6 metres if area up-slope and 3 metres if area down-slope of swimming pools, property boundaries, driveways and buildings
  3. Details on topography, soil composition and vegetation within the intended disposal area (this includes presence of rocky outcrops, slope, areas of poor drainage, etc).
  4. Position of any environmentally sensitive areas (including native bushland, watercourses, intermittent waterways, Environmental Protection Zone B, etc).

Please Note:

  1. Failure to supply the above information may result in processing delays.
  2. Council requires that all wastewater applications are prepared in accordance with recommendations in Environment & Health Protection Guidelines and Australian Standard 1547:2012.
  3. Council will assess the application for the above system, and may require a site capability and system design report to be undertaken if:
    • the intended irrigation area is located within the prescribed buffer distances
    • fill is located in the intended irrigation area
    • the site is located in an environmentally sensitive area (i.e. Environmental Protection Zone B)
    • the only available area for irrigation is also to be used as a recreational area
    • any major site limitations are present that will impact on the absorption of wastewater or uptake of nutrients
    • the system is not the most suitable for the site

The following table outlines approximate areas required for disposal fields. These figures are to be used as guides only*.

NUMBER OF
BEDROOMS
SOIL TYPE
SANDLOAMCLAY LOAMLIGHT CLAY
2 120m 180m 220m 300m
3 180m 220m 300m 400m
4 240m 300m 350m 500m
5 300m 400m 500m 600m

* A reserve area equal to the primary area is also to be shown on the site plan.

Installation of AWTS

  1. Irrigation lines must be buried at a depth of 100 mm below finished ground level (in accordance with AS 1547:2012).
  2. The irrigation area cannot be used for growing fruit, vegetables or other consumable products.  The irrigation area cannot be used as a recreation area and must not support animal, vehicle or pedestrian traffic.
  3. Sprinklers must have a maximum throw of two metres, and the plume must be no greater than 400mm from the finished ground surface.
  4. Sprinklers are to be installed approximately one every 20m2 (subject to site specific conditions) and operational at all times.
  5. Irrigation must occur only in designated effluent disposal areas.

Download AWTS Information

Required information for the installation of Composting Toilets

When lodging your application, the following information must be supplied in order for Council to assess your application.

  1. Manufacturer’s plans and specifications indicating tank/s dimensions and capacity, plus the licensed plumber’s name, address, phone number and licence number.
  2. An accurately drawn, detailed site plan drawn to scale and showing:
    1. The position of the house, including aspect.
    2. Floor plans for the dwelling showing all bedrooms, study, rumpus room, etc.
    3. The sanitary fittings of the house (including toilet(s), bathroom(s), kitchen and laundry wastewater disposal points) with internal and external drainage to wastewater tank(s) marked.
    4. The position of the composting unit.
    5. The position of the greywater tank(s), ensuring at least 1.5m distance between tank and dwelling, property boundaries, driveways and any impervious surfaces.
    6. Property boundaries and a brief description of adjoining and adjacent land uses (e.g. dwellings, native bushland, recreation areas, watercourses - including drainage easements, creeks, dams, etc).
    7. The position of the intended grey water disposal area.
    8. Position of roof, surface and subsoil drainage pipelines to their point(s) of discharge.
    9. Position of any environmentally sensitive areas (including native bushland, watercourses, intermittent waterways, Environmental Protection Zone B, etc).
    10. Available area for burial of composted material produced in composting unit.

Please Note:

  1. Failure to supply the above information may result in processing delays.
  2. Council requires that all wastewater applications are prepared in accordance with recommendations in Environment & Health Protection Guidelines and Australian Standard 1547:2012.

Download Composting Toilets System Information

Required Information for the installation of a Greywater Treatment System

When lodging your application, the following information must be supplied in order for Council to assess your application.

  1. Manufacturer’s plans and specifications indicating tank/s dimensions and capacity, plus the licensed plumber’s name, address, phone number and licence number.
  2. An accurately drawn, detailed site plan drawn to scale and showing:
    1. The position of the house, including aspect.
    2. Floor plans for the dwelling showing all bedrooms, study, rumpus room, etc.
    3. The sanitary fittings of the house (including toilet(s), bathroom(s), kitchen and laundry wastewater disposal points) with internal and external drainage to wastewater tank(s) and/or sewer marked.
    4. The position of the greywater tank(s), ensuring at least 1.5m distance between tank and dwelling, property boundaries, driveways and any impervious surfaces.
    5. The intended disposal area/method of treated greywater, including details, plans and specifications of the reuse of the greywater.
    6. Property boundaries and a brief description of adjoining and adjacent land uses (e.g. dwellings, native bushland, recreation areas, watercourses - including drainage easements, creeks, dams, etc).
    7. Position of roof, surface and subsoil drainage pipelines to their point(s) of discharge.
    8. Position of any environmentally sensitive areas (including native bushland, watercourses, intermittent waterways, Environmental Protection Zone B, etc).

Please Note:

  1. Failure to supply the above information may result in processing delays.
  2. Council requires that all wastewater applications are prepared in accordance with recommendations in Environment & Health Protection Guidelines and Australian Standard 1547:2012.
  3. Council will assess the application for the above system, and may require a site capability and system design report to be undertaken if:
    1. The intended irrigation area is located within the prescribed buffer distances.
    2. Fill is located in the intended irrigation area.
    3. The site is located in an environmentally sensitive area (i.e. Environmental Protection Zone B).
    4. The only available area for irrigation is also to be used as a recreational area.
    5. If any major site limitations are present that will impact on the absorption of wastewater or uptake of nutrients.
    6. The system is not the most suitable for the site.

Download Greywater System Information

Required Information for the installation of a Research / Alternative System?

Research of alternative systems for onsite sewage management need to be assessed on an individual basis. This type of system will usually require an accompanying site capability and system design report, prepared by a suitably qualified wastewater consultant.

Ongoing maintenance, as a condition of approval, will involve regular monitoring of effluent quality AFTER treatment has occurred. It is advisable that applicants contact the Environmental Compliance Team on 9847 6829 or compliance@hornsby.nsw.gov.au before submitting an application to determine the level of detail required in the eventual submission.

Download Research System Information

Required Information for an Onshore Vessel Sullage Water Pump-out System

When lodging your application, the following information must be supplied in order for Council to assess your application.

  1. Manufacturer’s plans and specifications indicating septic tank and collection well(s) dimensions and capacities, plus the licensed plumber’s name, address, phone number and licence number.
  2. An accurately drawn, detailed site plan drawn to scale and showing:
    1. The position of the tanks, the draw-off pipe and the suction outlet at street level. Note that tanks must be located a minimum of 1.5m from any building, driveway or any impervious surfaces.
    2. A contour plan from tanks to draw-off pipe.
  3. Water use details utilised in the sizing of the system, including volume of fresh and salt water used in vessels within the past twelve months and forecasted water usage.
  4. Details of fixtures and fittings associated with the transfer line, including material type, couplings and pump capacity.
  5. Details of oil/water separators to be place in series with the pump out system, including capacity and maintenance schedule.

Please note:

  1. Failure to supply the above information may result in processing delays.
  2. Council requires that all wastewater applications are prepared in accordance with recommendations in Australian Standard 1547:2012), Australian Standard 3542 – Pleasure boats – Toilet waste collection, holding and transfer systems, and Septic Tank and Collection Well Accreditation Guideline (NSW Health, 1998).
  3. If holding well is installed in a position lower than the pipe outlet, a pump must be installed. This pump must be capable of delivering a flow rate of 364 L / min at the outlet.
  4. If the holding well is installed in a position higher than the pipe outlet, a lockable gate valve must be installed at the draw off pipe.
  5. In situations where placement of the pump-out pipe is through another property, an easement must be created. This may require assistance from solicitors and must adhere to Council’s “Terms of Easement” conditions.

Download Onshore Vessel Sullage System Information

Approval to operate

All owners of existing sewage management systems must hold a valid Approval to Operate (Licence), which helps Council monitor and manage the impact of pollution in local areas. The Approval to Operate also ensures property owners are aware of their responsibility to operate and maintain their system.
Download an Onsite Sewage Approval to Operate form

Are you concerned about a neighbour's onsite sewage?

If you have concerns about the onsite sewage management on a nearby property you can ask Council to investigate. Click here to lodge a sewage investigation request

Further information

Should you have any questions about your onsite sewage treatment system, phone Council's Environmental Compliance Team on (02) 9847 6829, email compliance@hornsby.nsw.gov.au or visit www.health.nsw.gov.au

You may also wish to consult the Easy Septic Guide here.