Just thought I’d jump on here as we are also doing KDR in GRC, have a low level property and are going through CDC. GRC do have final say on the stormwater design unfortunately. Which sucks because the whole point of CDC is efficiency but it’s not when you still need council engineer approval. (Side note: it’s taken us 6 months to do cdc waiting for stormwater approval. Anyone else experiencing ridiculous delays??)
We don’t have to get an easement but we did need a refusal letter signed by our rear neighbours. We’re proposing a charged system and it meets council’s requirement of draining by gravity from boundary to kerb. Not an engineer so apologies if I’m butchering the explanation haha. We’ve been told there were some amendments required from council this week but sounds like not major enough to tell us what (so I’m assuming charged line is a go). Hoping to FINALLY get approval next week.
Just our personal experience, but hope you can find an alternative solution other than easement.
Is your Garage RL higher than the boundary RL? This would be the most critical thing re charged systems in our area, and for most low level properties, they cannot achieve fall from the garage to the street kerb, meaning a pump out, or absorption is required - which GRC usually always refuses. So, I think your case may be simpler than you think.
Also your explanation was quite good :p