Stormwater connection for new granny flat on low side

If my property is on the low side of the road (i.e. slopes towards back) how does one typically sort out the stormwater connection for a new granny flat? I'm doing everything under CDC approval not council DA. I definitely don't want a charged line.

Is it as simple as connecting to the existing stormwater pipe used by the existing house? Does the SEPP allow this? Or do I need to deal with back neighbour?

 

What's wrong with using a charged line?

 

Where does the existing house go? If it runs down passed the proposed gf, you can just tap into it

 

Depending on the degree of slope on the backyard where the granny flat is, it may or may not be possible to get storm-water off the granny flat roof to run uphill to the street.

There are a few options:

1. rubble / stormwater disposal pit, which captures the run-off and let's it soak away
2. tap into a stormwater easement at the rear (if not on your land you may need neighbour's permission and pay them for the privilege)

 

As others said,

Easy options are:

Charged line and/or rubble pits

Tapping in to neighbours stormwater pipes will require paperwork and one off/ongoing payment.

Best to get stormwater engineer to draw out suitable solution!

 

I can't get my head around how the dirt / silt that will collect at the lowest point of the charged line will get pushed out to the street whcih could be 10m away and uphill - does anyone have any experience in owning charged lines, are they a hassle re maintenance?

 

A granny flat i had built on my parents site uses a charged line. My understanding (and i could be completely wrong) is that it is simply gravity.

Water flows from the highest point to the lowest point.
So the highest point would be the roof gutter, the lowest point, well is the lowest point. With a charged system, there is always going to be water collected/retained at the lowest point. But when it rains water collected from the roof gutter pushes all existing in the pipe out.

Note: There is nothing mechanical about it at all.

 

That would make the most sense and be the cheapest way - but it doesn't seem to be mentioned as a commonly done thing, e.g. this article by Granny Flat Approvals doesn't list it as an option - is it really this simple?

Yes that's right, but I still can't imagine the dirt can be pushed all the way out - maybe just the lighter particles but the heavier stuff will stay, also with the long dry periods it will harden and I'd imagine every year or so I'd need to get a plumber to use his jetter to clear it. Has this been your experience? Maybe I imagine a much worse situation than reality haha

 

Call a plumber, quick 5Min call should confirm, but if the current house goes somewhere there shouldn't be major issues tapping in * but there are always exceptions.
Water runs down hill and doesn't like being complicated, either does council! A GF isn't collecting a huge amount of water so unlikely to overload the pipe

Have you put an offer in yet?

 

Would a plumber know whether I'm allowed to tap into the existing pipe used by the existing house or is this a question for the private certifier? I'm sure physically it's possible and probably quite easy for the plumber, the issue is permission.

I put in a half decent lowball today, fingers crossed.

 

You can tap into the existing house sewer/stormwater. That is how it is done.

 

It's your pipe you can do what you like. Storm water is the poor neglected cousin to sewer. Council pretend they care but the storm water networks everywhere are in poorly managed