We know quite a bit about your dilemmas with the hydraulic water pump to discharge your stormwater. As you've seen on our thread we were horribly disheartened to hear this news at our tender appointment.
Does your land have much fall?
A couple of suggestions for you, and believe me, we have done so much research on this one:
1. You mention an easement running along the back of your property for sewer use. Sewerage will not help you here (South East Water). What you need to find is a stormwater discharge pit in this easement in one of your neighbours land. Henley would have already applied for a legal point of discharge from your council, and presented that document to you today. This doc will contain any evidence of council stormwater drainage pits.
2. If you are lucky enough to have a discharge pit nearby, then you can have Henley draft up a letter to take to your neighbours so you can access the easement during the construction. We were fortunate with ours. Our hydraulic pump quote was $16K. Using the easement option and draining in a pit 2 houses down came in at just over $5K.
3. You can contact your local council and ask for their stormwater engineer (yes, they have them), and ask advice about your block and use of pumps vs curb & channel draining. Be warned though, that they may say your block is set for curb & channel drainage, but what the builder says goes.
4. You can engage another builder to look over your drawings, and site survey (may come at a cost) to see whether they believe you can build with a cheaper stormwater discharge option.
5. Enquire about having a gravity fed system (charge pump) instead of a hydraulic pump - much cheaper, and I have horrible fears of a hydraulic system breaking down and flooding everything - Imagine going away on holidays??
6. Lastly, if all else fails, and you have no other option but a pump, look at buying one for yourself from ebay. Work hard with Henley if you pursue this option to make sure you purchase the right one. My brother bought a hydraulic pump for his house at a grand cost of a few hundred dollars!!
Can I add, that after we had our tender, I spoke to my consultant who informed me that most of the costs in our site cost estimates were provisional (some were non-negotiable), I mean we had provisions for a franna crane and spotter $5K, Arborist $1K which are not a guaranteed use. Our tender presenter didn't give us the impression these were provisional.
Good luck, I hope you get the result you're after. I know the horrible feeling of shock after tender.
Thanks so much for the info kirst81! This is probably our last sticking point in terms of going ahead so i'm hoping we can resolve.
Our land has a bit of a slope but not much. From the front to back it starts at 100.06 and slopes down to 99.49. From west to east it slopes from 99.85 to 99.6. To build the house we will have three "steps" that have quite gentle slopes between them from the front to the back with the slab going on the middle plateau.
The council don't appear to be very helpful although admittedly we haven't spoke to them directly. On all of the plans/maps the council have provided, there is no stormwater access for our block. Further, there is no access for any of the houses on our side of the street or to the houses around the corner from us. Based on the plans, the closest access is across the road and uphill. I find it hard to believe that none of the houses near us have access to a stormwater drain so i'm hoping the easement is the answer and its just not on the drawings! About 4 or 5 house behind us there is a large open stormwater channel so i'm hoping that somehow our stormwater is linked into that.
Our tender presenter said that a drainer was coming to look at the property today to see if he could work it out but we haven't heard anything.
Thanks again for all the other options you gave, we have already started investigating them and you tips are extremely useful.