Browse Forums Building A New House 1 Jun 03, 2012 10:40 pm Hi i am building a house in Castle Hill area. (comes under Baulkham Hills shire council) can someone please answer the following questions regarding onsite stormwater detention system. How much does it cost to get the Hydraulic plans done for onsite stormwater detention system, do we have to go through the builders for this or can we get this done on our own. We have been quoted $ 3000 for the drawings and report by the engineer and $46000 for construction of a 27.5 cubic meters of underground tank (under the driveway) and plumbing from this to the council drains on the street. It was shocking to find such a large amount being required after the whole tender process bank loans had been finalised. Please help us by giving advice and sharing your experiences. Re: onsite stormwater detention system 2Jun 03, 2012 11:03 pm Was this quote from your builder? If you have a copy of your contour map, try taking it to the local council to talk about it. I don't know about your council, but Ryde council have a walk in service for people to talk about these things. It may also be worth getting a second opinion from an independent hydraulic engineer to see if there's a cheaper solution. Re: onsite stormwater detention system 3Jun 03, 2012 11:27 pm Building your tank under the driveway is the issue. Its a massive engineering problem. I considered it, then I found these: http://www.landscapetanks.com.au/ I talked to the director of the place at the sydney home show, and he reckons it won't be a problem in Baulkham Hillls (I'm building in North kellyville). I plan to use at least on as the front fence for the raingarden requirement, and 1 or 2 at the back for the water tank requirement. I haven't actually got this approved yet, but hope to negotiate it with my builder this week. Re: onsite stormwater detention system 4Jun 03, 2012 11:29 pm Why do you need 27000 litres of water retention? Thats like a swimming pool size. Our requirements are 3000L and a raingarden... Re: onsite stormwater detention system 5Jun 04, 2012 12:13 am Thanks for the reply, We also have an additional 5000 litre above ground rainwater tank. I don't understand why we need a 27.58 cubic metre detention tank. Our land area is 701 m2 and built area will be 42 squares. Thanks for the info daveinthehills, i will discuss this option with my builders as well. At least this would be of some use for us. Do we have to go with the builders for the detention tanks etc. We have already paid $3000 to the builders for the Hydraulic designs through their engineer. Who does the construction of the detention tank as per the hydraulic engineers design, the engineer or the builder? Can we use the plans from one engineer and go to another for construction of the detention tank? Thanks again for your help Re: onsite stormwater detention system 6Jun 04, 2012 9:17 am dollysydney How much does it cost to get the Hydraulic plans done for onsite stormwater detention system, do we have to go through the builders for this or can we get this done on our own. We have been quoted $ 3000 for the drawings and report by the engineer and $46000 for construction of a 27.5 cubic meters of underground tank (under the driveway) and plumbing from this to the council drains on the street. Hi, who gave you these figures, was it your builder? If yes, is this part of the job in your contract with them? Is your builder a 'small' builder or is your house one of the project homes/builders? Much of this depends on what is your contract like (if you are there already). If the builder hasn't done / spend any of that work / money yet, it's still just a quote and you can always get your own quotes, I can give you a firm's name ... And was it the BH council who made the OSD a "must" requirement for your house? Oh, and is your block really slope-y?? What stage is your build/contract/tender in?? My signature is distracting people from my wise posts ... Re: onsite stormwater detention system 7Jun 04, 2012 9:22 am Oh, just noticed that you already paid the 3k ... so hardly a need for another engineering plan for the same thing ... Now that you already started that process, I suspect it would be best to let the builder complete it since he would then be responsible from start to end. But then again, you can never know ... Also, where is the OSD going to be installed on your land/house? Under the house, or is it independent from the actual build?? My signature is distracting people from my wise posts ... Re: onsite stormwater detention system 8Jun 04, 2012 9:38 am Hi Lex, thanks for the reply, OSD was not part of the contract with the builder. We are with the Baulkham Hills shire Council. We found out about this after the DA application was submitted to the council. Ours is a project home and the builders have been pretty good with us from the start. Our block is pretty flat with slight slope, fall towards the front. The plan from the Hydraulic engineer is suggesting to build the detention tank under the driveway. 27000 litres capacity is huge, i want to know what other alternatives are there. I would also like to know if the price quoted to us is reasonable. On the same strip that we are building there are other new homes and our neighbour has spent $20000 on underground tank at the back. Another neighbour has spent $30000 for above ground but this included retaining walls that he had to build for the property anyway. Wonder why the difference. Re: onsite stormwater detention system 9Jun 04, 2012 9:58 am 27.5 Cubic isn't to bad to incorporate underground. Wouldn't personally put under driveway though. Can you incorporate in your landscape (under turf?) somehow? Landscape Design & Construction http://cherub.squarespace.com/ Re: onsite stormwater detention system 10Jun 04, 2012 10:34 am Hi Cherub thanks for the reply. Looks like you are in the landscaping business yourself. One of the members have suggested "landscaping tanks" as an alternative to detention tanks in the earlier posts. Would appreciate if you can give feedback on this. Thanks Re: onsite stormwater detention system 11Jun 04, 2012 10:47 am Haven't used them (look pretty inflexible in design terms), without seeing the plans hard to give to much sound advice. But would be more inclined for a harvest solution, were you collect the used water back into the detention tank (hence under turf option) Landscape Design & Construction http://cherub.squarespace.com/ Re: onsite stormwater detention system 12Jun 05, 2012 7:23 am Hi dollysydney, you must be in some of the new areas/streets? You can also try calling the council to discuss your various concerns and see if there is any other way out of this, just make sure you get onto the right person there, like a senior bldg surveyor. And if you must have the OSD, like Cherub said, I would also be looking to see if there is any "free" area on your land, like turf, and not under the driveway! You can never know if things or components are going to fail and need maintenance etc ... so the better the access, the easier for you later on. Just out of interest, is there a proper stormwater drainage on your (or other) block?? Are there pipes coming out of people's kerbs onto the street? My signature is distracting people from my wise posts ... Re: onsite stormwater detention system 13Jun 05, 2012 6:24 pm Thanks for the info everyone, have forwarded this to the builders, let's see what they come up with! Re: onsite stormwater detention system 14Jun 05, 2012 6:38 pm Hey dolly, Are you building in castle wood estate? We have recently sold our house in the area but I know the new release about 5years ago all required onsite detention systems and were averaging 50k, if you did it under the driveway, the only other option is large open area in your front yard which looked silly, have a drive down Darcy road and check out some of the homes, some literally have big holes in their front yard, the developer put a huge onsite tank in the park on the corner which catered for about half the homes, however in heavy rain, the park would flood, we used to watch kids in their paddling on boogie boards etc. Unfortunately don't think there's a cheap way out Re: onsite stormwater detention system 16Jun 06, 2012 8:04 am There was a new release about five years ago of about 50 blocks, and there has been a few smaller subdivisions of 4-6 blocks since. We lived in a very small culdesac and there will 6 or 7 blocks coming on soon in there( they only subdivided one half of road 20 years ago) average price will be $750k apparently We thought about buying one as the guy at the top owned them all, it has been in the pipeworks for about 5 years. They have already put one big onsite detention tank on one block of land that will service all blocks Re: onsite stormwater detention system 17Jun 06, 2012 9:57 am Hi Lex, I rang up the council couple of times and have been told off for calling frequently anyway doesn't look like there will be any help from that side. Most of the houses on the strip are new and the neighbours i have spoken to have either aboveground or underground detention tanks but none of them have such a huge capacity (27.5 cubic metres) @gogo we are not building in castlewood estate, our block of land is off Tuckwell Rd, new release (one strip with 15 blocks) Re: onsite stormwater detention system 18Jun 07, 2012 12:31 pm dollysydney I rang up the council couple of times and have been told off for calling frequently anyway doesn't look like there will be any help from that side. However, on second thought, if that's what the council really requires for your particular area, there's probably not much you/they can do (but you can never know unless you try). Sometimes they do allow exceptions, provided that your written supporting arguments are reasonable. My signature is distracting people from my wise posts ... Re: onsite stormwater detention system 19Oct 16, 2012 11:38 am Hi everyone i have come back on the forum after a long time. I thought i will update information regarding the issue so that it helps other people. * Please make sure the Hydraulic drawings are for the correct catchment area, this will increase or decrease the price. * Due to incorrect Hydraulic plans drawn initially, there was a delay in council approval. * The total cost was $32887 for the tank 21cubic metres and plumbing. * We decided to do this with the builder so that it comes under warranty. We took quotes from 3 other people and there was a difference of $5000. We did not want to take the risk. * Our tank will be built under the driveway, to avoid wastage of space. Unfortunately there was no way out, we are with Baulkham Hills Council. The officers at the council were very supportive and helped us throughout the process. Hope this info will be helpful for others. Cheers Plumbers 'can be' plumbers, made all the worse by self certification which the building surveyor invariably accepts as proof of compliance! The good thing is that you know know. 3 4835 Grab a hose, insert it at the top of the inlet/down pipe and turn the water on and see where the water is escaping from. Then you'll know. 3 8454 in the stormwater pit or the drain? Those dont look like theyd fit in the drain. Separately, the pits do get stuff in them during the course of the build. For the most… 1 7928 |