After receiving a few rejections from neighbours to run a stormwater pipe through their yards, I'm turning to other options to subdivide the block and obtaining a lawful point of discharge. Has anyone done trenching (digging to the mains pit on the street) or filled their site and retained to gain stormwater access through the front of the block? What sort of costs did you hit? I'm trying to work out rough feasos but have no idea what numbers to factor in. For filling, there needs to be at least 2000m of soil at one point, with multiple retaining walls. For those in the know, should I be factoring 25K, 50K or even 100K?