Granny Flat Plumbing and Sewerage Guide


When it comes to granny flats Melbourne has seen a real rise in the popularity of these types of homes in recent years and given the rising hour’s prices it stands to reason that people have been looking for alternatives. There are a number of challenges with these types of properties which builders must get past, however, the first of which is that the size is small and that requires some careful planning and some real creativity to make the place feel as big as possible. Another challenge comes in the shape of plumbing, and that is something which we are going to take a look at today.

Whilst you are likely to already be sat on top of a property where there is plumbing installed, it is a tough task to navigate the right sewerage and the right plumbing for this annexed building.

Rule of Thumb

Generally speaking, the suggestion is that you build the draining of your granny flat lower than where the existing mains is, the pipe which feeds water into the property. If however, this is not the case then the drainage water will go into some underground pit and that will then need a pump to be installed to get rid of it, not to mention the fact that the council may have a slight issue with that kind of setups, in fact, they definitely will. This is a simple design which basically uses gravity to clear through the drainage from the granny flat.

Checking The Rules

Another important thing to know is that you are only allowed to have one connection from the council sewer into a property, which means that the water from the granny flat is going to have to connect to the line from the main property. This can be problematic so it is essential that you get things checked out first, otherwise you run the risk of having to create a new junction or paying the council to cut open the main pipe.


It is absolutely essential that you remember that this work has got to be carried out by a registered and licensed plumber, it does not work which you are able to undertake yourself. Australia is very strict on this so before you even consider doing the work on your own, you should remember that you have to get a fully licensed professional plumber. If you do this work with someone unlicensed or on your own unlicensed then you will find that you could be fined or the plumber which has been registered to your granny flat could lose their license. There is no point in running this risk as, beyond the rules around it, there is a high chance that a mistake could be made which will lead to an expensive outcome.

Read more: Restorations and repairs by Service restore

The key to getting this work done well and done right is to pick a great plumber in your area, preferably someone who actually specializes in work on granny flats. Do your research around what you can and cannot do and if you are in any doubt at all then speak with your local authorities.

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