Browse Forums Building A New House 1 May 09, 2009 4:58 pm Hi Hoping to get some help on rainwater tanks We have 2 areas of wall-space (4-5m) which are separated by an area of about 6m of windowed walls. <--space--><--windows--><--space--> ....4-5m.........6m.........4-5m We're considering putting in 2 banks of slimline 5000 litre tanks with a downpipe going to each of the 2 banks, on each wall space but need to know if they can be connected by a pipe running underneath the windows. Like this: [][]________[][] Each tank would have it's own overflow to the drain. One of the 5000 litre banks would be attached via a pump to the toilets and laundry, but we'd like to use the water from both banks of 5000 litre tanks. So the question is - Do tanks have to be connected at the top (which we can't do as the pipe would have to go across the windows) or can they just be connected at the bottom (without a pump to get water between the tanks)? I saw this, but am not sure if the piping could be stretched across 6m between banks of tanks Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Does anyone know? Thanks, PN Re: Can you connect multiple rainwater tanks just at the bottom? 2May 09, 2009 6:00 pm Sorry I don't really know. But a few thoughts... The water will obviously equalize between all the tanks, so if say you have one tank full worth of water, it would be divided between all the connected tanks and you end up with say 5 tanks which are all 1/5 ful (instead of 1 full tank)l. One way to solve that problem is to put a valve between each tank, this would allow you to keep each tank shut off until the first one fills up. Tank one fills with water, you open valve between tank 1 and tank 2 then the water would equalize so there is half in each tank, next time you do this both tanks would end up 3/4 full etc. I'm sure you see where I'm getting at. Obviously you would never be able to 100% fill any tanks apart from the first, but you'd get pretty close I reckon. So I'm not sure if it's the best idea, but I don't see why it wouldn't work. Re: Can you connect multiple rainwater tanks just at the bottom? 3May 09, 2009 6:19 pm Don't see why it wouldn't work. I assume you're running the pipe along the back edge of the tanks. Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Can you connect multiple rainwater tanks just at the bottom? 4May 09, 2009 6:29 pm All you need is connect the tanks at the bottom. Also, you only need one overflow .. if tanks are the same, then overflow can be on either tank (I would recommend the tank with the inlet). If tanks are not the same, you'll need overflow on shorter tank. Note, connecting the tanks at the bottom will tend to stir up the sedimentation. Also, need to keep the tanks clean ... otherwise, connection pipe can be prone to blocking (thus, my recommendation to put overflow on the inlet tank). Chris Re: Can you connect multiple rainwater tanks just at the bottom? 5May 09, 2009 8:44 pm Pebble Sorry I don't really know. But a few thoughts... The water will obviously equalize between all the tanks, so if say you have one tank full worth of water, it would be divided between all the connected tanks and you end up with say 5 tanks which are all 1/5 ful (instead of 1 full tank)l. One way to solve that problem is to put a valve between each tank, this would allow you to keep each tank shut off until the first one fills up. Tank one fills with water, you open valve between tank 1 and tank 2 then the water would equalize so there is half in each tank, next time you do this both tanks would end up 3/4 full etc. I'm sure you see where I'm getting at. Obviously you would never be able to 100% fill any tanks apart from the first, but you'd get pretty close I reckon. So I'm not sure if it's the best idea, but I don't see why it wouldn't work. Thanks for the reply. I also thought that logically the water should equalise and hence would share itself equally across all the tanks. It's just that when we asked someone at Bunnings (we just happened to be there when there was some rainwater tank Q&A session going on) the Bunnings guy looked at us as if we were weird to suggest it and said that tanks were always connected at the top. Re: Can you connect multiple rainwater tanks just at the bottom? 6May 09, 2009 8:45 pm Casa2 Don't see why it wouldn't work. I assume you're running the pipe along the back edge of the tanks. We were thinking of running the pipe along the back edge of the tanks so that the pipe was flush against the house wall Re: Can you connect multiple rainwater tanks just at the bottom? 7May 09, 2009 8:49 pm ChrisL All you need is connect the tanks at the bottom. Also, you only need one overflow .. if tanks are the same, then overflow can be on either tank (I would recommend the tank with the inlet). If tanks are not the same, you'll need overflow on shorter tank. Note, connecting the tanks at the bottom will tend to stir up the sedimentation. Also, need to keep the tanks clean ... otherwise, connection pipe can be prone to blocking (thus, my recommendation to put overflow on the inlet tank). Chris Thanks for the info. We didn't know if that 1 overflow would be enough, as we weren't sure how long the tanks would take to equalise when water was coming into one or two of them (if we had 2 lots of downpipes feeding into two of the tanks). The tanks would be the same. I did wonder about the sediment build-up and whether this would be an issue to connecting from the bottom. Re: Can you connect multiple rainwater tanks just at the bottom? 8May 09, 2009 8:58 pm Suggestion - Have a gate valve to isolate when full... reason - If you suffer a failure of plumbing(putting tanks in series) you will lose all your water I appologize if this was mentioned earlier I speed/skip read Our 2 large 90kl & 100KL tanks are hooked up so when filling they balance. Once full I isolate and then the overflow comes from one source, one set of drainage. Sediment is not an issue, we have upstand outlets and filtration before the pump Where you are coming from is where you are going to... Re: Can you connect multiple rainwater tanks just at the bottom? 9May 09, 2009 8:59 pm Both is possible P, we are going to have 3 concrete in-ground tanks and were given the option to connect them at the bottum. Obviously that would not be a good choice for us as you don't want to dig 2.7 meters deep in case of a problem. So our tanks are going to be connected at the top and the overflow goes from to tank to tank until all 3 are full and the rest of the water will flow to our dam. We also have a 3000 ltr Colorbond Slimline tank and that one has connections on the bottom. Re: Can you connect multiple rainwater tanks just at the bottom? 10May 09, 2009 9:11 pm onc_artisan Suggestion - Have a gate valve to isolate when full... reason - If you suffer a failure of plumbing(putting tanks in series) you will lose all your water I appologize if this was mentioned earlier I speed/skip read Our 2 large 90kl & 100KL tanks are hooked up so when filling they balance. Once full I isolate and then the overflow comes from one source, one set of drainage. Sediment is not an issue, we have upstand outlets and filtration before the pump That's really helpful. Thanks We'll definitely look into the gate valve. It's great to know that the sediment is not an issue as that was worrying me. Re: Can you connect multiple rainwater tanks just at the bottom? 11May 09, 2009 9:13 pm Annelies Both is possible P, we are going to have 3 concrete in-ground tanks and were given the option to connect them at the bottum. Obviously that would not be a good choice for us as you don't want to dig 2.7 meters deep in case of a problem. So our tanks are going to be connected at the top and the overflow goes from to tank to tank until all 3 are full and the rest of the water will flow to our dam. We also have a 3000 ltr Colorbond Slimline tank and that one has connections on the bottom. This real world examples are really helpful. Thanks As the overhead pipes aren't an option for us (due to the windows) it would have to be bottom connections, or just a single 5000 litre bank (due to spare limitations we have to use slimline and have only got space for 5000 litres in any one location on that wall). Re: Can you connect multiple rainwater tanks just at the bottom? 12May 09, 2009 9:25 pm I think I said gate valve I meant ball I have gate and ball, the gate are a pain...600turns or a 1/4 turn ball Where you are coming from is where you are going to... Re: Can you connect multiple rainwater tanks just at the bottom? 13May 09, 2009 9:28 pm onc_artisan I think I said gate valve I meant ball I have gate and ball, the gate are a pain...600turns or a 1/4 turn ball Ok - thanks Shows what I know about valves Re: Can you connect multiple rainwater tanks just at the bottom? 14May 10, 2009 12:16 am I don't think anyone mentioned yet that the two tanks that are connected need to be installed at the same level, otherwise the higher one will never fill up before the lower one overflows. Built the C£arend0n Cambridge: Moved in. Happy campers. Here's our story on HomeOne I might be old, but I have no trouble finishing my... er... Re: Can you connect multiple rainwater tanks just at the bottom? 15May 10, 2009 12:24 am HellDad I don't think anyone mentioned yet that the two tanks that are connected need to be installed at the same level, otherwise the higher one will never fill up before the lower one overflows. The side of the house is all the same level so that shouldn't be an issue in this case. Thanks for the tip though It could have proved to be an annoying oversight if the area wasn't all level. Re: Can you connect multiple rainwater tanks just at the bottom? 16May 10, 2009 5:51 am We were having the same problem purpleninja - thanks for asking the question has been very helpful Re: Can you connect multiple rainwater tanks just at the bottom? 17May 10, 2009 8:16 am Glad to help If anyone else has any experience on this please share it as it's really helpful to hear what others have done. Thanks Re: Can you connect multiple rainwater tanks just at the bottom? 18May 10, 2009 1:10 pm It works Ok connecting them at the bottom. A tap of some type to be able to turn each one off is nice to have. The main issue you'll have with the inlet and overflow on the first tank, with a heavy downpour the first tank fills up- and due to the smaller pipe that joins them at the bottom you get less flow through this pipe - so in heavy rain the 1st tank may start overflowing before the other tanks are actually full. So you end up with the 1st tank full when it stops raining, and then as it feed through to the other tanks you end up wih all of them being 1/2 or 1/3 full, when it might have been a result of all 3 tanks being 100% full if the water could have got there faster. But do whatever you can to suit the situation. Steve Re: Can you connect multiple rainwater tanks just at the bottom? 19May 10, 2009 1:42 pm Yak_Chat It works Ok connecting them at the bottom. A tap of some type to be able to turn each one off is nice to have. The main issue you'll have with the inlet and overflow on the first tank, with a heavy downpour the first tank fills up- and due to the smaller pipe that joins them at the bottom you get less flow through this pipe - so in heavy rain the 1st tank may start overflowing before the other tanks are actually full. So you end up with the 1st tank full when it stops raining, and then as it feed through to the other tanks you end up wih all of them being 1/2 or 1/3 full, when it might have been a result of all 3 tanks being 100% full if the water could have got there faster. But do whatever you can to suit the situation. Steve Thanks for the info. That would be a shame if we lost out on all the tanks filling due to the slow transfer rate. Do you know if it's possible to use larger pipes (than the standard narrow ones) to connect the tanks - hence allowing faster flow through between them? Re: Can you connect multiple rainwater tanks just at the bottom? 20May 10, 2009 1:51 pm In regards the ball vrs. gate valve, always use a ball valve. The gate valves have a thin spindle that after a few years of use tend to snap after being tightened down into the off position, staying in the off position. That was always going to be a challenge and a test of patience. Full marks to your mate. Did you discuss the wet area near the trampoline? 16 17324 18 90422 |