Obtaining neighbours OK to run stormwater pipes through their yard.

Hi all,
This is my first ever post so I'm officially a newbie on here! I've just put a contract on a property in Tarragindi (Brisbane QLD) which is a run-down post-war on an 810m2 two-lot block, with the intention of demolishing and building two new homes, and are currently just a few days into due-diligence.
Town planners have advised that due to the slope of the block (slopes away from the road, approx 3-3.5m slope across the length of the block), we would need to obtain the rear neighbours approval to run a new stormwater pipe through their backyard, or there's no chance of progressing a development on this site. Does anyone have any experience with tackling this sort of situation, and any tips for how best to approach the neighbours? Odds of agreement? On the positive side, it would be positioned down their property boundary (not cutting through the middle of it), in an area clear of structures (but does have at least one tree), and I'd be happy to compensate them for the inconvenience and return the lawn etc to it's previous condition etc. However, as I understand it, they are completely within their rights to say no, so therefore I presume the best strategy would be to find this out now, and if they indicate they wouldn't cooperate, i presume we should probably pull out before the due diligence period comes to an end? Have any of you been in this situation? Any advice would be much appreciated!
Welcome noobo

I'd suggest some low level stalking before approaching them, riffle through theirs bins etc, find out what they're into, what they drink. Then cautiously approach and perhaps bring up compensation of so many cases of xxxx or a set of golf clubs.

You'll need to know the size of the pipe and equipment that would be used etc as they'll want to know the level of destruction, how long it will take and how you'll make sure its as good as it can be after. You might need to turf a larger area or put in a garden or something to keep them happy.

Ive put in quite a few km of sewer pipes and although these people benefited directly it still had head aches!! Really comes down to the person and how you talk to them, don't use letters do it direct and know what your talking about have a likely plan of what's required. If you give the wrong info or be airy fairy it will bight you!
If I was approached I would expect fairly substantial compensation for making a 3m strip along my block very difficult to build on, if I wanted to subdivide. + being paid for the inconvenience.
Call Carol Williamson of BRW Enterprises in Toowong on 3876 0088. They do nothing but plumbing consultation / hydraulic engineer work, day in and day out, and often know of solutions "outside the box".
I did a development where there was no stormwater at all so we had to have a massive pit in the front with 2 pumps in it and the stormwater is pumped uphill and out into the gutter
The documentation you need is as follows

1. BCC Property owners consent or refusal - CC10835.
download from

2. A stormwater sketch plan. This plan needs to accompany the consent form and be signed by the neighbour.

DRW Consulting will do a professional sketch plan up for around $200. It will show the proposed line so you can show the neighbours. Phone 3341 1444.

(If you gain consent attach 1 and 2 above to your development application as proof of consent for council).

3. Attach an information sheet to the sketch plan for the neighbour

I am going through the same process as we speak.
good luck
Thanks everyone. In particular, thanks Rustymutt for those links - please let us know how you go with your situation and I'll be sure to update within this thread as to how we go.

Does anyone know if BCC would approve the pit & pump method mentioned above by fernfurn?