Browse Forums Building A New House 1 Sep 15, 2012 10:42 am After not paying the builder his last 5% because he never wanted to finish and fix defects we got an inspection and the report noted that we needed a drainage pipe to catch excess water against the house. This was fine and we started digging to install the aggie pipe. We have a 5000L tank on that side of the house which the gutter & down pipes flow into. Now we got confused because we could not find the storm water and then found all the pipes backed up with water. We called our neighbour landscaper who said we have a blockage, so he cut a hole in the bottom of the pipe and dirty water gushed out. We freaked and called the plumber. He told us that our gutter and storm water flow into the tank and that the pipes are always full of water. ???????? Can someone explain why they have done this. I don't like the idea of water pressure in my pipes 24/7. It is the height of my water tank. Plumber has not installed a first flush system to the tank which I use for my toilets and garden and I don't have overflow on the gutters. This does not sound common. To drain the aggie pipe, we now have to add a new pipe along side the water filled one and connect it to the pipe infront of the water tank to the storm water. Re: Drainage and water tank head of water 2Sep 15, 2012 11:12 am I'd like to comment but need to clarify some bits as they are confusing or not specific enough. So ... my Qs in blue After not paying the builder his last 5% because he never wanted to finish and fix defects we got an inspection and the report noted that we needed a drainage pipe to catch excess water against the house. Is your house cut in?? How deep is the cut (approx)? Now we got confused because we could not find the storm water Have you found the storm water PIPES? (if the pipes are what you were looking for) and then found all the pipes backed up with water. Which pipes are backed up?? We called our neighbour landscaper who said we have a blockage - WHERE is the blockage??! , so he cut a hole in the bottom of the pipe - WHICH PIPE? and dirty water gushed out. We freaked and called the plumber. He told us that our gutter and storm water flow into the tank and that the pipes are always full of water. ???????? This is normal I'd say Can someone explain why they have done this. I don't like the idea of water pressure in my pipes 24/7. It is the height of my water tank. Plumber has not installed a first flush system to the tank which I use for my toilets and garden and I don't have overflow on the gutters - Are you referring to the little slits in the gutter? . This does not sound common. To drain the aggie pipe, we now have to add a new pipe along side the water filled one and connect it to the pipe infront of the water tank to the storm water. Any pics? My signature is distracting people from my wise posts ... Re: Drainage and water tank head of water 3Sep 15, 2012 11:35 am We have a wet system i believe. The end of the downpipe underground was cut. No house is not cut in just sheer wall where rain hits, water got nowhere to go. On one side of house, downpipes go underground and back up into the water tank. It's a reasonably big house. Builder has not installed pops, rainheads, filters, first flush, diverters, nothing and water in pipes is very dirty. Tell me how to upload photos to you.. Thanks so much There is no blockage, that was simply water in the underground pipe which when he hit it sounded blocked. Re: Drainage and water tank head of water 4Sep 15, 2012 1:26 pm McKinnon 1. the report noted that we needed a drainage pipe to catch excess water against the house. 2. We have a 5000L tank on that side of the house which the gutter & down pipes flow into. 3. Now we got confused because we could not find the storm water 4. and then found all the pipes backed up with water. 5. We called our neighbour landscaper who said we have a blockage, so he cut a hole in the bottom of the pipe and dirty water gushed out. 6. We freaked and called the plumber. 7. He told us that our gutter and storm water flow into the tank and that the pipes are always full of water. ???????? Can someone explain why they have done this. 8. I don't like the idea of water pressure in my pipes 24/7. It is the height of my water tank. 9. Plumber has not installed a first flush system to the tank which I use for my toilets and garden 10. I don't have overflow on the gutters. This does not sound common. This thread should have been posted in the ECO forum. 1. The BCA requires that water must not pool against the house and a minimum fall away from the house is regulated. Also be very careful when digging against the house that you do not disturb the termite barrier. 2. When you say downpipes (plural), this argueably indicates possible non compliance. The Vic PIC states that the tank's overflow pipe must be at least the same size as the inflow pipe. This is to prevent the inflow overwhelming the overflow pipe during a major rain event, causing the tank to overflow. Is this where the "excess water against the house" is coming from? However, the regulation is poorly written as a wet system pipe can carry water from several downpipes and the PIC do not refer to flow capacities or the minimum overflow pipe size for roof areas harvested . The overflow outlet also has a mosquito proof mesh barrier. The mesh restricts flow and can also clog with floating organic matter. If you determine the gutter's high points for each diverted downpipe, you can then calculate the total roof area harvested. This area then needs to be multiplied by a figure based on the roof slope. For a standard 23 degree pitch roof, you need to multiply the roof plan area by 1.21. You will then be able to establish whether the roof drainage into the tank is compliant for the tank's overflow size. In most instances where a tank sited next to the house is serviced by an additional wet system, the installation will not be compliant. Plumbers are not trained in rainwater harvesting and most installs are sub standard and/or not compliant. 3. The overflow drains into the stormwater. 4. This is a wet system. 5. Was this pipe buried? If it is a 90 mm UPVC stormwater pipe, it should not be buried. Wet systems also build up a lot of debris as the velocity required to flush the debris up the vertical riser is much greater than the flow of water during anything but extreme rainfall. This debris then breaks down and will often cause stagnation that will pollute the tank. It is common for the horizontal pipe to eventually block. Wet systems fitted with vertical risers are compliant but should be considered sub standard installs. 6. So the unqualified neighbour damaged the pipe and you then called the plumber??? 7. To harvest additional downpipes. A 5,000 litre tank will not fill from one downpipe and the nearest accessible downpipe might be harvesting a small roof area. The wet horizontal pipe should have IOs fitted so that the horizontal pipe can be flushed to remove debris. Was your pipe fitted with these? 8. One metre of water is 9.8 kPa. It is unlikely that the pressure from your tank when full would generate much more than 20 kPa. Don't be confused by the weight of the water in the tank as weight and pressure are entirely separate. If weight over-ruled pressure, then you could syphon water uphill. The horizontal pipe, if 90 mm UPVC, is unsuitable as already explained. If the system was correctly set up, having clean water in a 100 mm DWV horizontal pipe would not be a problem provided that the overflow was correctly sized. 9. A flush system is not required for compliance. Most of the gutter's silt and other muck is only flushed from the gutter during heavy rain and this is long after the first flush has filled. First flush systems are not a magical panacea. 10. If you are referring to slots, slotted gutters have a reduced effective carrying capacity (referred to in the regulations as the cross sectional area) and are regulated to harvest a smaller roof area than the same size unslotted gutter. This regulation is often not adhered to (non compliance) and is why slotted gutters often overflow during rainfall that is less than a 1:20 ARI for which eaves gutters are meant to be designed for. For some strange reason, people seem to put up with these overflows. Why is this also an issue with the tank and what area of Melbourne are you in? 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Drainage and water tank head of water 5Sep 15, 2012 9:09 pm http://www.flickr.com/photos/59690559@N ... hotostream http://www.flickr.com/photos/59690559@N ... hotostream http://www.flickr.com/photos/59690559@N ... hotostream http://www.flickr.com/photos/59690559@N ... hotostream http://www.flickr.com/photos/59690559@N ... hotostream http://www.flickr.com/photos/59690559@N ... hotostream http://www.flickr.com/photos/59690559@N ... hotostream http://www.flickr.com/photos/59690559@N ... hotostream 3 downpipes go into the tank. Re: Drainage and water tank head of water 6Sep 15, 2012 9:45 pm Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Drainage and water tank head of water 7Sep 15, 2012 10:51 pm Your rainwater harvesting system is a typical install but it is also most probably not compliant. It will cause some serious issues down the track. Without knowing the total roof area harvested by the three downpipes, l can still make an educated guess and say that the overflow is unlikely to have the capacity to prevent the tank overflowing during medium-heavy rain. If so, the roof area harvested exceeds compliance for the overflow pipe size. There do not appear to be any mosquito proof leaf diverters fitted to the two wet downpipes as required. If the buried pipe is 90 mm UPVC, it should not have been buried. This is also typical. The buried horizontal pipe will eventually block and trapped debris could also cause stagnation. From the photos, l cannot see any IO's and this should be investigated. If there are not at least two, it is not compliant. From the photos, it appears that the height of the two 100 X 50 X 90 mm downpipe adaptors that convert the 100 X 50 mm rectangular downpipe to 90 mm round is not much higher than the infeed pipe that enters the tank. From this, l am assuming that the rectangular downpipe is either PVC or a metal downpipe that has been subjected to plenty of silicone. Nevertheless, the adaptor has probably been sealed so that the downpipe will still provide sufficient head when the tank is full without water spilling from the adaptor. If this is the case, then the downpipe could fill if the flow through the horizontal pipe became restricted. This would be a potential problem in that the water would then overflow from a fair height. It would be best to check and see if the adaptors have been sealed given the other concerns with the horizontal wet pipe. You will have to monitor the sediment build up in the tank. I cannot judge from the photos the height of the tank outlet that feeds the pump but if it is close to the bottom, it could draw sediment through the pump. This will not only block any filters you may later install, it can also damage the pump through a condition known as erosion corrosion. Note that a poorly positioned tank outlet is not a compliance issue but it is a common and amateurish mistake. I would also like to see a photo of the connection from the tank to where it connects to the pump. Have a read of this Vic. PIC Technical Solution Sheet. http://www.pic.vic.gov.au/resources/doc ... _tanks.pdf 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Drainage and water tank head of water 8Sep 15, 2012 11:37 pm Thank-you so much for your advise. Seeing the builder left in dispute I now have to fix many things that the inspection report found defective. I live in Melb, Glen Eira if that helps. I will send better photos. I am so upset Collingwood won. I hate em! Re: Drainage and water tank head of water 9Sep 16, 2012 12:57 am He may not have fitted leaf diverters (also eroneously known as rain heads) due to aesthetic reasons but you really do need them. Apart from anything else, they stop mosquitoes accessing the water and breeding. For an easy fix, l think that l would fit a sediment trap to the buried horizontal pipe. I have described it in my second post on this linked thread... viewtopic.php?f=35&t=59393 The 90 mm pipe is easily adapted to 100 mm by using a 100 mm F + F coupling and a 100-90 mm reducer socket. You should really do away with the 90 mm UPVC pipe but it is there and you may as well continue to use it. IOs are mandatory but next to useless with buried pipes and l would rather have the sediment trap in any case. The third downpipe can be retained as it can be replumbed so that it has its own filter and overflow, that way the tank's overflow would only service the excess inflow from the other two downpipes. I cannot mention how this is done on the forum. By making some simple changes, the water would be very clean and potential overflow problems could possibly be eliminated. You are not far from me but l don't do plumbing, just advise. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. 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 17953 Need more photos from around the house including your gutters. We have had 3 of the wettest years in a row for some time so that wouldn't be helping 3 7315 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 11293 |