If you are building on a block sloping downhill from street, what storm water system did you need and how much did it cost you?
Specially if you had no legal point of discharge!!
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Browse Forums Building A New House Re: Stormwater drainage/ OSD/ pit pump/ absorption trench cost 2Jun 16, 2025 7:28 am Architectural Homes & Duplexes - specialising in custom designing homes to your budget Get a Free Onsite Consultation Today or send a PM for information, questions or advice.  14 May 2025 11 Junior Member Re: Stormwater drainage/ OSD/ pit pump/ absorption trench cost 3Jun 16, 2025 8:00 am Thank you so much. I wonder what weather scenario is for those two cases where you had to get underground tanks connected to the street. Our lowest point is that the lower back corner and the street is 52 m away. As the side boundaries are 52 m this would be a lot of length that they ask us to connect from the lowest point to the street. There’s a lot of anxiety to live with for X amount of months until we know the plan and costs! Thanks again.  Ashington HomesHi KDR4everhome Firstly congrats on starting your forever home journey. We build mainly on sloping sites in Ryde, Ku-ring-gai, Willoughby & Northern Beaches council areas which all have similar stormwater requirements. I hear that Parramatta are a bit difficult. I don't have any personal experience with them, but the costs to build the different systems across different council areas will be the same, so I can help you out with that. Attached are some plans for a typical absorption absorption trench on a down sloping site similar to yours. The red arrow shows the absorption trench part of the system. In it's basic form it is a hold in the ground, full of blue metal and pipes with holes. Pretty basic. The actual cost of a system like this from a plumber is circa $3,000 to 4,000 plus gst, Although what the builder charges you is unknown. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ There are other variations on this. Sometimes the engineer will specify part absorption and part charged, again this doesnt cost very much. Where it gets expensive if you need an underground tank at lowest point and you need to pump back to the street, but this is relitively uncommon. We have only had to do that twice. Its hard to give a give a cost as the size of the tank can vary greatly, anything from a couple of thousand litres to 20,000 litres, and that could set you back $40-50,000. I hope that helps a bit Cheers Simeon 14 May 2025 11 Junior Member Re: Stormwater drainage/ OSD/ pit pump/ absorption trench cost 4Jun 16, 2025 8:54 am Does this type if stormwater design go automatically to DA? Can CDC approve it if the plans are certified by stormwater engineer ? Ashington HomesHi KDR4everhome Firstly congrats on starting your forever home journey. We build mainly on sloping sites in Ryde, Ku-ring-gai, Willoughby & Northern Beaches council areas which all have similar stormwater requirements. I hear that Parramatta are a bit difficult. I don't have any personal experience with them, but the costs to build the different systems across different council areas will be the same, so I can help you out with that. Attached are some plans for a typical absorption absorption trench on a down sloping site similar to yours. The red arrow shows the absorption trench part of the system. In it's basic form it is a hold in the ground, full of blue metal and pipes with holes. Pretty basic. The actual cost of a system like this from a plumber is circa $3,000 to 4,000 plus gst, Although what the builder charges you is unknown. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ There are other variations on this. Sometimes the engineer will specify part absorption and part charged, again this doesnt cost very much. Where it gets expensive if you need an underground tank at lowest point and you need to pump back to the street, but this is relitively uncommon. We have only had to do that twice. Its hard to give a give a cost as the size of the tank can vary greatly, anything from a couple of thousand litres to 20,000 litres, and that could set you back $40-50,000. I hope that helps a bit Cheers Simeon Re: Stormwater drainage/ OSD/ pit pump/ absorption trench cost 5Jun 16, 2025 11:09 am  KDR4everHomeDoes this type if stormwater design go automatically to DA? Can CDC approve it if the plans are certified by stormwater engineer ? Ashington HomesHi KDR4everhome Firstly congrats on starting your forever home journey. We build mainly on sloping sites in Ryde, Ku-ring-gai, Willoughby & Northern Beaches council areas which all have similar stormwater requirements. I hear that Parramatta are a bit difficult. I don't have any personal experience with them, but the costs to build the different systems across different council areas will be the same, so I can help you out with that. Attached are some plans for a typical absorption absorption trench on a down sloping site similar to yours. The red arrow shows the absorption trench part of the system. In it's basic form it is a hold in the ground, full of blue metal and pipes with holes. Pretty basic. The actual cost of a system like this from a plumber is circa $3,000 to 4,000 plus gst, Although what the builder charges you is unknown. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ There are other variations on this. Sometimes the engineer will specify part absorption and part charged, again this doesnt cost very much. Where it gets expensive if you need an underground tank at lowest point and you need to pump back to the street, but this is relitively uncommon. We have only had to do that twice. Its hard to give a give a cost as the size of the tank can vary greatly, anything from a couple of thousand litres to 20,000 litres, and that could set you back $40-50,000. I hope that helps a bit Cheers Simeon Normally if they have the correct engineer you can go CDC. Do you mind me asking if you are using a project home builder as this could impact the process Architectural Homes & Duplexes - specialising in custom designing homes to your budget Get a Free Onsite Consultation Today or send a PM for information, questions or advice. Hi All We have a 2000L rainwater tank planned, and currently the OSD Basin 1 is proposed to be above ground in the backyard with surrounding… 0 54 If a house in sloping downhill hill by 2 meter below street gutter level - no legal point of discharge, neighbours declined easements - gravity system not a option… 0 61071 Looking at those pics, the main problem is water pooling because the yard’s too flat and shaded. If you just lay pavers or pebbles, the water will still sit there.… 1 13653 |
