Skip to content
Free chat

From the studio

What should i do if there is a sewer main running through my site?

If a sewer main is close to where you want to build, you need to check its depth and consult an engineer to ensure foundations are far enough back.

What should i do if there is a sewer main running through my site?
Shea Cullen, Registered Architect at Good ArchitectShea CullenNSW Registered Architect 9748 · Updated 6 July 2026

It depends on where the sewer main is exactly. If it is well away from the house or on the street then you should be ok. If it is close to where you want to build then you really need to check its depth and consult an engineer to make sure the house footprint and foundations are far enough back.

How Do I find out if there is a sewer where I want to build?

The easiest way is to go to the Dial Before You Dig website and lodge an enquiry with your address. Then have a look at your water provider plans to see where it sits on the site. Here in the Central Coast, the Central Coast Council manages water and sewer so you need to check their plans for the sewer location. If you were in Sydney it would be Sydney water to check., if you were in Newcastle it would be Hunter Water plans to check for sewer location.

What is a sewer peg out?

A sewer peg out sets out the exact location and depth (invert) level of the sewer so that your engineer can design it according to the council guidelines which can be found here.

What is a long Section?

A long section will show you the invert levels for a sewer. It is not as accurate as a sewer peg out, it is good to have at the feasibility stage though so that you can ask your engineer how far away the footings and building footprint need to be. It costs $42.18 from council, there are directions on how to apply for it below.

How to apply for a Long Section through Central Coast Council

  1. If you don't have an online services account for Central Coast Online Services Property and Payments Portal, apply for one here. It will take about two days for council to get back to you and then you'll be able to login.

  2. Login to Central Coast Council's Property and Payments Portal here.

  3. Select Apply for a Certificate:

Central Coast Council apply for a certificate webpage with two workers pictured

Apply for a certificate, click on this image on council's website

4. Click on Long Section:

Central Coast Council certificate price list with the Long Section option ticked

5. Select your Address:

Council property portal address search form with the street details highlighted

6. Write in the address and then select the address:

Council portal search results showing one matched Wyoming property

7. Select your Address again:

Council portal confirmation screen with the Long Section certificate selected

7. Fill out the form and pay the cost (about $42.18).

6. Council will then come back to you with the long section that will let you know your levels, give it to your engineer and architect so they can start designing to the council guidelines which can be found here.

It is a good idea to also get a sewer peg out done when you get the initial survey done so that you have the best information. I recommend getting both because the cost is small compared to the cost if something goes wrong and you end up excavating a sewer when building.

This is definitely a prerequisite for if you are building near a sewer.

Render of a curved balcony townhouse development on a street

Thinking about a
project?

We take on a small number of projects at a time, so you get Shea, not a junior. There is usually room to start something new.

Book a free 15 min chatTalk to Us
4.9 out of 5 from 15 Google reviews