Browse Forums Owner Builder Forum 1 Mar 23, 2011 3:47 pm Hi Everyone, We are currently building a house on a rural block in Perth and therefore there is no scheme water so we installed a 130KL tank. Our house is nearly completed and soon I'll have to plumb the downpipes to the tank to collect water. Has anyone know whats the best way to harvest it. I defenitely want it to go underground then to the tank but not sure how many downpipes from the house I need to use? Would 1 or 2 be enough which are closest to the tank or need to use all of them? Can I run the pvc pipes underground myself or do I need a licence plumber? and is there a certain depth i need to run the pvc pipes? Any experience from anyone who has done it or knows about it would be appreciated. Thanks Re: Plumbing to Water Tank 2Mar 23, 2011 8:38 pm If you do a search online for number of downpipes required, there is a good website (can't remember the link) that helps you calculate how many downpipes you need and how much water will be harvested. There are also good websites (do a search for rain IQ) which can tell you how much water you will collect off your roof. If you have a giant roof and don't need to collect from all of it, then reduce down number of feeder downpipes. For me with a 300sqm roof, I need all downpipes (8 of them) to feed my 105K tank. I would think you need more than 2. Building tip No. 3: A raft slab will not get you down a river. A waffle pod slab does not go with maple syrup. My building thread https://forum.homeone.com.au/viewtopic.php?f=31&t=53000 Re: Plumbing to Water Tank 3Mar 23, 2011 9:08 pm For every mm of rain your roof will collect 1 ltr per sq mtr. Weatherzone might give you an average annual rainfall in your area Where you are coming from is where you are going to... Re: Plumbing to Water Tank 4Mar 23, 2011 9:31 pm This link will show you how to calculate how much water you can collect. http://www.anewhouse.com.au/?p=653 The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Plumbing to Water Tank 5Mar 23, 2011 10:32 pm barker If you do a search online for number of downpipes required, there is a good website (can't remember the link) that helps you calculate how many downpipes you need and how much water will be harvested. There are also good websites (do a search for rain IQ) which can tell you how much water you will collect off your roof. If you have a giant roof and don't need to collect from all of it, then reduce down number of feeder downpipes. For me with a 300sqm roof, I need all downpipes (8 of them) to feed my 105K tank. I would think you need more than 2. Hi Barker, I have searched the net for number of downpipes required and no luck so thats why I posted it on this forum. As far as calculating how much water I'll collect of my roof well I did found many websites on this. My roof area is approx 500sqm so I assume since you needed all of your 8 downpipes then I guess I will need all of mine. The reason for my original question was to find out so if I only needed of 2 or so then this would save me some digging Thanks. Re: Plumbing to Water Tank 6Mar 23, 2011 10:48 pm I thought I was being greedy 500 sq mtrs... well a couple well placed downpipes draining large areas of roof to collect the bulk then 132kl would take no time... however the remaining roof runoff needs to be removed from the site so that rising damp doesn't become an issue. If your annual rainfall is in the 1000mm range a LOT of water will be available.(500Kl) In some countries the local community council will collect for you and pay you for it. Street front water tanks are also the rage in NZ, US, Germany, Holland etc. We are dumb and very slow on the uptake here, we have had it too easy for too long. Since we are the driest populas country on earth pretty silly really. Where you are coming from is where you are going to... Re: Plumbing to Water Tank 7Apr 05, 2011 11:44 pm I would say that you would want to put as many downpipes as practical as when it rains in perth it absolutely dumps and because you're relying on rainwater for your potable supplies you would want to collect as much as possible. Not sure about depth of pipes but your council or tank supplier may be able to help you there. As a guide, sewer pipes require 600 mm cover (i.e. from the top of the ground to the top of the pipe) and require a gradient of 1 in 60. Generally, the minimum pipe gradient for stormwater is 1 in 100. Make sure that you locate your underground tank to allow for these grade changes. You will also need to bed the pipe on some crushed rock. Re: Plumbing to Water Tank 8Apr 06, 2011 8:07 pm I have a rural property as well, and we are not on mains water. I would advise you collect all water from all downpipes anr run them to the tanks. If you get too much water, its easy to take the overflow from here and direct it where ever you like. You dont need to worry about the gradient if you use a wet system, but make sure your tank inlet is lower than the gutters. If you can avoide using 75mm PVC, its an advantage. 90 and 100mm pipe is very cost effective, and less likley to block up with the kids tennis balls - why do they make them such a snugg fit?. (the flow is also better if several downpipes flow into the one common run to the tank) Hope this helps Re: Plumbing to Water Tank 9Jun 27, 2011 11:54 am i watched a friend do his hook up to his tank about a month or so ago he had either 8 or 9 downpipes dug a trench with one of them digger things (cost him 280 to hire it for the day) all around the house, about a meter or so from the slab at a depth of roughly 300mm he bought all his piping and they just started on one corner and worked their way round to the tank glued them all together and hey presto it was basically a big ring around the house with t joins coming off and hooking up to the bottom of the down pipes (with a few 45 degree elbows on each down pipe) he joined it all up on the corner the tank was on then ran it (under ground) to the tank and then up the tank and in to the top of it when it rains the whole system fills with water and when its full pushes the water into the tank he then had a pump with a regulator on top of it beside the house that was hooked up to both the tank and mains water if he wants to run off mains because his tank is low, he just turns a lever above the pump, and then in winter when the tank is full he just turns the lever back make sure the rain water tank is lower than the gutters by about 100 mm (was his advice) otherwise it obviously wont flow i was there to see how he did it and it looked pretty easy tbo, i backed filled for him as we went around took all day tennis balls are killer!!! get some guttering mesh of some description imo If you can calculate the reasonable charged head from let's say 100mm below the gutter to the top of where the vertical riser's horizontal discharge pipe will be, that… 11 17539 Building Standards; Getting It Right! Thank you for the generous offer. I need to get the plumber out to give me an explanation. As mentioned I haven't seen any rain water discharge from pipes 1& 3. It… 7 10834 Can a plumber put a tap on a rain water tank which is full? Tank is similar to one in photo. Cheers. 0 1670 |