Subdivision Restrictions

Restrictions you may face

Engineering constraints may prevent you from subdividing your land.

Engineering constraints are important, and if a site has a topography falling towards a street, you can be reasonably assured most of the required infrastructure such as sewer, stormwater and water mains are likely also located in the same street. This is not always the case and service locations should be reviewed as early as possible. ‘Dial Before You Dig’ offers a free and valuable service to confirm service locations by submitting a search request at

As sewer and stormwater are gravity systems, the site must fall towards an existing or proposed sewer and stormwater connection for a subdivision to be possible. A ‘Dial Before You Dig’ search is not sufficient alone to determine if a site can be serviced as it doesn’t show the depth of relevant mains. If they are not deep enough to service the site, alternate mains may be required. There can also be capacity issues that could prohibit a subdivision in an area with costly upgrades required potentially at the developers’ expense.
Does the lot fall away from the street?
Any land falling away from a street (rear falling) will usually have a sewer either passing along its lowest point or through the neighbouring property. Where a main sits in a neighbouring allotment, there will likely be a single sewerage connection provided to the site. A single connection can’t be used to service more than one allotment, and all lots must be provided with an independent sewer connection directly from a sewer main.
Where an existing main is located in a neighbour’s property, the property owner’s written consent is required to gain access to their land and undertake works to augment the sewer network and provide sewer connections to the new lot/s. Likewise, stormwater is nearly always required to drain through a pipe to a lawful point of discharge, and quite often, this may be to a street at the rear of a site passing through a neighbour’s property. As with the sewer, written consent from the neighbour is required to construct a stormwater pipe through their property, and in some cases, provide easements to council over the sewer or stormwater mains.
If agreement is required to undertake works in a neighbour’s property, but the neighbour has not consented, in many cases council will not approve a subdivision over the site. However, some council’s do not assess water and sewer services where there is a separate water corporation and can approve a subdivision application without assurance these services can be provided. There is a risk that in these circumstances council will approve a subdivision that cannot be acted upon if sewer and water cannot be connected if any consent from neighbours hasn’t been provided.
Each council has different policies on stormwater management, but the requirement to connect to the reticulated sewer system is usually always the same. For larger subdivisions, some may allow a private sewerage pump station to enable sewerage to be pumped uphill to the nearest reticulated sewer main, however this approach is inconsistent between different jurisdictions.

Is the site on a combined drain?

Allotments within Brisbane’s pre-war inner city suburbs may have a combined drain, which can be an issue. In the 1930s, reticulated sewerage systems were installed on a budget, and combined drains servicing up to three homes, were commonly installed. This means each allotment doesn’t have its own sewer connection directly from a sewer main. All subdivision proposals require allotments to be serviced with a sewer connection directly from a new sewer main instead of the combined drain. For this to happen, consent of all affected property owners is required and the developer will fund the works, unless commercial terms can be reached between the properties owners.
If you are planning to renovate your home on a site with a combined drain, please be aware you are restricted to four additional plumbing fixtures (toilet, sink, bath, tap or shower) before an allotment must be removed from a combined drain. Whether you are subdividing or extending your home, with more than four additional plumbing fixtures you will need all affected property owners’ to consent to works through their property. If this is not possible you will not be able to subdivide the site or add more than four fixtures.
It’s a good idea to get an engineer to review any proposed subdivision. Not only to help identify any constraints, but also to provide an estimated cost for any required civil works.

It pays to get the right advice

An engineering review of any proposed subdivision is always recommended as part of the due diligence process to identify any constraints which may apply. An Engineer is also often able to assist in providing budget estimates for the cost of civil works required for a subdivision.
Contact Consult Planning for your subdivision project to ensure that you have all the necessary advice to make your project a success.