How to build over a sewer pipe

by | Jan 19, 2023 | Advice & inspiration, Building basics & regulations, Building tips

Sewer pipes are one of those everyday necessities we tend to take for granted. However, when it comes to constructing a new home or addition, you cannot afford to take an out of sight out of mind approach to any pipes under your building site. But what are the rules when it comes to building over or near sewer infrastructure? Let’s take a deep dive into how to build over a sewer pipe.

Different councils will have different rules when it comes to building over a sewer pipe. It’s vital that you check with your local council every time you build. All our information is South-East Queensland specific.

Can you build on top of a sewer pipe?

Yes, but there are a few big “ifs”. Whatever you’re planning, it’ll need to comply with the Queensland Development Code MP 1.4 or otherwise be approved. The key details to being approved are that your building work won’t:

a) adversely affect the operation and functional needs of the sewer lines

b) place too much weight on the sewer or do anything that could damage the infrastructure.

c) interfere with the maintenance of the sewer lines.

d) put you or anyone else in harm’s way.

To build over a sewer, you’ll need to gain council approval. You’ll also likely need a structural engineer to help you create a design that will meet all the necessary requirements outlined in the code.

Unsure whether you can build over your sewer line? Get in touch with us to discuss the situation and get our expert opinion.

What is the Zone of Influence?

When it comes to sewer pipes, there is what is known as a sewer zone of influence. Imagine if you drew lines at a 45 degrees angle from the bottom of the sewer in each direction until they reach the ground surface. The area you’d have within these boundaries is the sewer zone of influence. The purpose of this is to determine what parts of the land are most likely to affect the sewer line.

Who are unity water and urban utilities?

Unity Water and Urban Utilities both provide similar water supply and sewerage services but in different areas. They’re statutory authorities run by their respective local governments.

Urban Utilities is an independent board but its shareholders are the Brisbane, Scenic Rim, Ipswich, Lockyer Valley and Somerset councils.

Unity Water is owned by the Moreton Bay Regional Council and the Sunshine Coast Council and services these two areas.

Depending on where you live, either Urban Utilities or Unity Water is responsible for the sewer lines leading to your property. Property owners are responsible for the pipes within their own infrastructure.

In Logan, Redland and the Gold Coast, water services are provided by the respective local council.

What are the rules for building over sewer pipes?

Rules for building over sewer pipes protect both your building and the pipe itself. If not properly thought out, the weight of your building could damage the pipes, which in turn to lead some very unpleasant substances leaking onto your property.

When building over a sewer, water main, stormwater drain or combined sanitary drain, the proposed building work will have to be assessed and meet Queensland Development Code specifications. To read the rules, click here for the official document. This outlines the acceptable solutions and performance requirements you need to meet.

Below is a general outline of where the rules specified in the ODC apply and where they don’t. If in doubt, it’s best to speak to your relevant service provider and double-check.

Where the rules apply

The rules outlined in the MP 1.4 applies to lots:

  • that contain relevant infrastructure or are adjacent to a lot that does.
  • which are adjacent to a road reserve that contains relevant infrastructure.
  • subject to a registered relevant service provider’s easement.

Where the rules do not apply

Building work that is at least or further than the minimum distance from the sewer infrastructure. This includes:

  • Clear from the zone of influence
  • 3 metres away for a Class 1 (houses or dwellings of a domestic or residential nature) or class 10 (non-inhabitable buildings and structures including sheds, carports, fences and swimming pools) building
  • 5 metres away from a Class 2-9* building
  • 5 metres away for driven piles and piers
  • 1o metres away for ground anchors and rock bolts

The rules also won’t apply to any internal alterations, repairs or changes to an existing structure or building so long as they don’t

* Class 2-9 buildings include boarding houses, apartment buildings, office buildings and more. Click here for more information.

How to get building work approval

To build over a sewer line, sewer mains or any sewerage infrastructure, you’ll need to apply with a building application to the relevant service provider.

Unity Water

Unity water requires to contact a qualified building certifier for any building work that is on or next to a property with water or sewer infrastructure or easement on it. If your work cannot meet the standards set out in the Queensland development code MP 1.4, you’ll need to make an application.

When applying you’ll need the following:

  • Site plans which show all existing and proposed buildings and structures, water and sewerage infrastructure and the property connections to said infrastructure.
  • a statement that illustrates which of the acceptable solutions you can’t meet and how your alternate solution still meets the related performance within the code.
  • elevation views of your proposed building work that shows
  • design drawings by a structural engineer that show the footings and groundings of your proposed building work and how they relate to the sewerage infrastructure.

While unity water will consider requests to approve building work that encroaches an easement protecting their infrastructure, they rarely grant them.

Urban utilities

Like Unity water, Urban utilities don’t accept self-assessment referrals, so you’ll need to contact a building certifier.

You’ll likely have to supply the same documentation as outlined for Unity Water.

Are my plans eligible for approval?

With various types of plans needing assessment, it’s difficult to know whether yours are eligible without hearing the specifics. For alternative solutions, an assessment manager will need to determine whether your proposal is feasible. Buildi will help you determine your new build’s chances of getting approval. We’ll also let you know if you may need to make adjustments.

Click here to book your free, impartial consultation today!


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