This is where we'll announce the most recent additions to our web site and council policies. If you've visited us before and want to know what's changed, take a look here first.


Current legislation known as 'Basix' has nearly been amalgamated with most council's Stormwater policy. Ask us if, or how your requirements to comply with stormwater guidelines can be 'reduced' by your requirement to comply with Basix. Contact Us


July 2020

Building and Development Certifiers Act and Regulation commenced on 1 July. Building Professionals legislation is now repealed and the Building Professionals Board is formally abolished. All functions carried out by the former Board are carried out by NSW Fair Trading staff. The Commissioner for Fair Trading is the ‘Secretary’ for the purposes of the new legislation. Owners now must complete construction and attain final occupation within 5yrs. Further details to be released.


Feb 2020

Georges River Council releases draft stormwater policy post merger. OSD reqiured for developments exceeding 55% site coverage and greater scrutiny on sites acceptable for charged systems.


July 2019

New SEPP code for mutli unit dwellings extended to more council areas


Sept. 2018

NSW postpones new legislation changing when a PCA can issue an interim occupation certificate.


July 2018

New SEPP code for mutli unit dwellings commences


May 2017

National Construction Code - NCC is updated and included numerous changes which are yet to  be co-ordinated with individual council DCP's


April 2015

Ku-ring-gai council updates DCP. Significant changes to policy deviating away from water conservation, and leaning more towards water quality measures. OSD is now mandatory and only 10% of the minimum rainwater tank requiremenst may be offset. Additional rainwater tank storage and bio-retention systems required.


August 2012


Warringah Council issues new OSD policy, which is intended to help streamline the design process for single dwellings only. Various changes to the code have been made which inlcude a simpler 40% site coverage rule before OSD is required, and storage requirement based on land area only rather then simulation of existing to proposed flows. In simple terms the storage requirements have increased significantly and generally now require some form or above or below ground OSD facility. The policy will be enforced from the 1-12-12. Various other technical changes have occurred also too detailed for this section. Contact ISC for further info.


July 2010


Ryde Council adopts draft DCP, which has been in the pipeline for quite sometime. Various changes to the code have been made which could eliminate the need for OSD, or provide a reduction in OSD via upsizing of raintank to a maximum of 5000L. Various other technical changes have occurred also too detailed for this section. Contact ISC for further info.


June 2010


Sutherland Council enforcement of DCP 2006 via DA consent conditions, as been relaxed after ISC consultation with council to adopt Rainwater concessions to Single Dwelling already under Basix legislation. In general, new homes requiring OSD that fall to the street or a drainage easement can provide a raintank of between ~5000_7000L in lieu of OSD.


December 2010


Sutherland Council gazettes Specifications for Stormwater Management of DCP 2006. All sites will essentially require OSD to ensure rate of runoff post development does not exceed that of pre development. Some exceptions do apply. Previously only the code was gazetted without an update to the specifications.


October 2009


Sutherland Council commences enforcement of DCP 2006 via DA consent conditions. All sites will essentially require OSD to ensure rate of runoff post development does not exceed that of pre development. Some exceptions do apply.


ISC invited by the AIBS to conduct training sessions throughout QLD for 2010.


June 2009


Ryde Council approves new Draft DCP allowing rainwater concessions for OSD up to 5000L. Watch this space to know when the DCP is formally adopted and can be used.


March 2009.


ISC conducts training presentation for the Australian Institute of Building Surveyors Brisbane Branch at the Pacific Golf Club Carindale. A turn out of over 35 members from the private and public sector made the event successful.


"All members found this to be the best presentation we have organised in the last 2 years of the branch's life. Was a good eye opener for all of us." - President of the Brisbance AIBS branch.

February 2009.


New Planning Code scheduled for release. ISC submissions and consultation with DOP, have pushed for a final amendment to the policy to allow absorption systems, however, all designs must be in accordance with the relevant councils DCP. ISC currently in consultation with several councils to implement assessment process for councils with complex DCP's based on merit design.


December 2008


Parramatta council will accept charged systems if hydraulic calculations provided. Preferred maximum of 500mm depth.


November 2008


Sutherland council now enforcing low level property policy through engineering department. Refusal letters must be sought if an easement cannot be obtained. Geotech permeability reports must then be obtained to determine soil characteristics and subject to report an absorption system and possibly OSD may be required.


October 2008


Pittwater council provides new alternative to OSD. OSD can now be provided internally of the raintanks  as a combined system. Condition is that the roof area must be greater than the new additional hard surface area being proposed.


September 2008


Sutherland council engineer, is now willing to consider charged systems to the street where easement alternatives have been absolutely exhausted and the depth of charging doesn't exceed 1m. ISC recommends client consult with a particular engineer in council, after easement alternatives have been exhausted and written evidence of such obtained, in order to gain consent to proceed with a charged system.


Canada Bay council implements internal policy changes to when OSD is required after meeting with ISC. Changes are complex. Email ISC for a breakdown of the changes.


June 2008


Ryde council planning policy preferences being adopted to OSD. Now limiting above ground OSD systems to larger sites where minimal impact occurs by retaining walls.


April 2008


Ryde Council will now consider low level properties exceeding 35% site coverage to approach a maximum of 40% if OSD is provided and an additional 6000L on top of Basix. Minimum backyard area still applies, being the hard surface area proposed must be equal to the available backyard area.


Sutherland council will no longer allow single dwelling concessions on low level properties. All low level properties will be required to prove they cannot obtain an easement. If an easement cannot be obtained than a Geotech report must be obtained in accordance with council DCP - Appendix A, and an assessment to confirm if absorption is a viable solution will need to be carried out.


Wingercarribee council confirms that no raintank compensation is being considered to offset OSD requirements.


March 2008


Bankstown council confirms alternative approach for driveway runoff to absorption trenches and pump out, currently in DCP. Transpiration Bedding 3m x 1m will now be acceptable.


Pittwater council commences implementing Amendments to LEP 21. OSD has tripled in volume requirement and rainwater tank concessions have halved.


January 2008


Ryde Council  new Urban Planning Policy creates obstacles with cost effective measures previously adopted. Council preference to tanks under driveway being considered. ISC currently investigating alternative methods of compliance.


Bankstown council now allowing smaller transpiration beds in rear yard for low level properties that require just their driveways to be catered for.


December 2007


Ryde Council adopts new Urban Planning Policy. Landscaping constraints become major obstacle for compliance of OSD. Smaller front yards due to rear setbacks increased.


August 2007


Ryde Council issues new draft Urban Planning Policy. Major ramifications to OSD may be adopted to eliminate above ground OSD systems based on the draft policy. Council is yet to confirm whether radical change will occur.


May 2007


Hornsby Council releases new policy on low level properties that can't obtain an easement. Owners now have the alternative if an easement can't be obtained of providing an additional 5000L raintank + Basix, and 12m of dispersal trenches. Conditions apply so contact ISC for further info.


March 2007


Warringah council now requiring construction certificate for stormwater separately to the house prior to the house construction certificate issued by the PCA. Similar to Baulkham Hills. Note that an accredited PCA must issue the stormwater construction certificate which is generally council.


January 2007


Lane Cove Council, require effective 10,000L raintank to avoid OSD connected to internal re-use. On average 12,000L is required to achieve the effective 10,000L


4th December 2006


Warringah Council, has updated policy on OSD compensation. All Raintank storage can be deducted from any OSD required storage, up to a maximum of of 50% of the OSD requirement. I.e 20cum of OSD can be replaced with 10cum of OSR and 10cum of OSD.


November 2006


Lane Cove Council, will now allow OSD requirements to be removed on a single dwelling site where a 10,000L raintank is proposed.


8th of September 2006


Lane Cove Council, to adopt new code very shortly. All Single dwelling that require OSD will be given the option to replace it with a larger rainwater tank. Watch this space for further details as it comes available.


20th of June 2006


Canada Bay City Council, adopts new code. All Single dwelling now require OSD unless an absorption system can be designed to accommodate the required runoff. Site coverage exceeding 35% will require a geotech report to confirm soil characteristics. Storage volume of approx. 8-12cum are anticipated.


30th of May 2006


Strathfield council has taken up the policy of NO charged systems to rainwater tanks. The implication are numerous, and will cost the average single dwelling considerably more than what Basix had estimated. Basix has taken a side line and is not willing to enforce the roof collection system as being part of the conservation system, and hence allowing council to enforce its no charged system policy to the harvesting system, which Basix has relied upon. Please ensure that you contact our offices before any design work commences for any applications to Strathfield Council, to ensure the design proposed can be achieved.


13th of January 2006


Bluescope Water's revised rainwater tank schedule of available tanks, which was effective on the 12th of December 2005.


Bluescope has advised that their older tanks will be available till the end of the month. Any existing jobs that have not yet been ordered, and were using tanks sizes no longer being produced, will have to refer to the approved design drawings, to check if alternatives were allowed for, and what limitations exists.


Another note to mention is that the Bluescope schedule refers to a Nominal storage and an AS3500 storage.

We have spoken to Basix, who are now updating their definitions, to state that the volumes required under Basix are the Nominal storages, and not that referred to as AS3500.

11th of November 2005


ISC makes major improvements to website to assist clients. Design Phases and downloads added. Low Level Properties explained.


14th of October 2005


Bankstown City Council's new DCP29 adopted on the 1st of June 2005, has now been re-interpreted. Chapter 11, now requires that all dual occupancy proposals that fall away from the street that cannot obtain a drainage easement and require an alternative method of stormwater drainage will require OSD, subject to a council assessment. All Single dwellings exceeding 66% site coverage will also need OSD.


1st of October 2005


Upper Parramatta River Catchment Trust implements Edition 4 Handbook to its 4 council catchment.


1st of July 2005


Basix now implemented in all NSW councils. Multi unit assessment tool available and compulsory from 1st of October 2005.


13th of May 2005


Bankstown City Council  issues new stormwater code DCP29.


21st of April 2005


Lane Cove Council to issue new stormwater code. Expected for June/July 2005. (Now anticipated for late 2005)


15th of April 2005


Ku-ring-gai Council Draft policy issued January 2005, expected to be in place shortly.


The amendment is mainly to correct some discrepancies with Basix, and some minor additional areas noted below:


1. Maximum above ground rainwater storage is 10,000L.

2. Maximum site coverage of 30% for sites that fall to the rear with proof that they cannot obtain an easement now have two options:

i. Site coverage exceeding 30%, can have the 30% to a dispersal system and the balance          roof may be charged to the street with a maximum of 2 downpipes and 150sqm.

ii. Pump out system for the balance exceeding 30% as in (i) above. Storage tank for pump out is high. e.g. 8700L for an additional 70sqm over 30% site coverage.

3. NO OSD required if site cannot obtain an easement and the above controls are met.


5th of April 2005


Upper Parramatta River Catchment Trust, to issue Revision 4 of the UPRCT OSD Manual in May 2005. Rainwater tanks will now be considered as part of the OSD subject to a number of variables such as no of occupants. Reduction in OSD is only marginal. Several other technical changes are being proposed. Council's affected - Parramatta, Holroyd, Blacktown and Baulkham Hills.

15th of February 2005


Ryde Council Amendment to DCP41 implemented. Email us for a copy.


1st of February 2005


Ryde City Council to implement Amendment to DCP41. maximum site coverage without On Site Detention requirements being enforced is 35%. Site coverage includes roof area (including gutters) and all hard paved areas. pervious paving will be consider (except for driveways) at 25% of actual area.






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