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Rainwater system and suggestions what to do with excess water


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Looking for suggestions on someone to install a rainwater system in Deep South, Cape Town.

I'm on a hill, top of the property is about 30m higher than the bottom.

 

House 1 (lower house)

I have a 2500L tank already fed from the roof.  (Probably could do with another tank or a much larger one as it fills to overflowing when it rains!)
Would like to feed the water into the toilet and use the rainwater for flushing, and for it to be fairly hands off.

Any people you can recommend?

 

House 2 (upper house, same plot; still being built)

I have a small stream of water coming down the mountain and ending up in the basement/garage.  Would like to save some of it, instead of using gravity to get rid of it (a hosepipe currently, dripping away day in day out).  It's not much water, but it's continuous, and seems to last a few months into summer, then gone till next winter.
I have plenty of space on the plot, and am not adverse to adding more tanks as needed.


Give me ideas!

 

 

 

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5 hours ago, shanghailoz said:

install a rainwater system in Deep South, Cape Town

Good idea. Although it will not save you money. I wish CT would subsidize initiatives like yours. Your project will help the city and you will still be able to shower without a bucket during the next drought 🤣.  CT gets about 400 liter rain/m^2/year. If you can afford it and have the space I would catch and store about have of that coming from your roof. In your case i would also catch the small stream. Although based on my experience (i have 40'000 liter storage) you will be able to fill the tanks easily with rainwater only. And as @Richard Mackayadvised, split the water supply in the house. I have not used any municipal water to flush the toilets and water the garden in years. I do not know of a company to design and install it for you. But if you lay out the set up and parameters any good plumber or builder will be able to do it for you.     

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7 hours ago, shanghailoz said:

I'm on a hill, top of the property is about 30m higher than the bottom.

That is a big advantage 🙂. i have a similar set up. I positioned a small (2500 liter) tank at the top of the property. The tank is used to gravity feed the rainwater circuit of the house and garden. With this set up you only have to pump water once in a while (this is cheaper and works well with a PV system).      

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10 hours ago, shanghailoz said:

Would like to feed the water into the toilet and use the rainwater for flushing

when you separate the plumbing it is a good idea to do it with a change over system. This will allow you to quickly switch back to municipality supply if there is a problem with your rainwater system.  

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I am currently renting in cape town northern suburbs.

The owner of this house has 5 5000l tanks that he used for his garden and so on. he never connected it up to the house because of the dirt. 

I asked him if we can implement a system where we can use the water for the toilets and the washing machine. 

We are busy with the one tank to install a pipe inside the tank that will draw water from about 30cm above the bottom, this way the dirt will stay at the bottom. He is also going to install a sand filter that will clean the water before it goes into the house.

All this will be connected using a pressure pump running off PV

I am using his place as the R&D because we plan to buy our own place. 

 

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8 minutes ago, Krokkedil said:

We are busy with the one tank to install a pipe inside the tank that will draw water from about 30cm above the bottom

i don't think this is necessary. The outlets are positioned sufficiently high above the bottom. My tanks have been in operation for 5 years and i never had a problem with dirty water. Last year i checked and cleaned the first tank the rain water enters the system (the tanks are connected in series). There was only about 5mm of sediment at the bottom. The other (downstream) tanks did not even need cleaning. I also do not have  filters on the in and outlets (except leaf strainers on the supply pipes).

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  • 2 weeks later...

I'm wanting to install a water tank between the house and the street. The house is 2m lower than the street and there is a wall to support the embankment.

Behind the wall is enough space to install the tanks if the ground is excavated. Is it ok to do this and if so can the tanks be buried in this area??

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Posted (edited)
1 hour ago, Richard Mackay said:

I'm wanting to install a water tank between the house and the street. The house is 2m lower than the street and there is a wall to support the embankment.

Behind the wall is enough space to install the tanks if the ground is excavated. Is it ok to do this and if so can the tanks be buried in this area??

Likely you'll need to speak to an engineer to get their approval for excavation there, so they can ensure that the existing wall will hold the load correctly.  Or advise as to what physical supports are needed to facilitate your request.

Council will need their sign-off for any work.

Edited by shanghailoz
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53 minutes ago, shanghailoz said:

Likely you'll need to speak to an engineer to get their approval for excavation there, so they can ensure that the existing wall will hold the load correctly.  Or advise as to what physical supports are needed to facilitate your request.

Council will need their sign-off for any work.

This would not be installed beyond the boundary of the property. But I accept that there might be a responsibility not to undermine the pavement structure..

The question is: can you bury a water tank in the ground??

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Posted (edited)
20 minutes ago, Richard Mackay said:

This would not be installed beyond the boundary of the property. But I accept that there might be a responsibility not to undermine the pavement structure..

The question is: can you bury a water tank in the ground??

https://www.nationalpolyindustries.com.au/2018/06/15/partially-or-fully-burying-poly-water-tanks/

 

Burying Poly Rainwater Tanks (guide only)

  1. YOU MUST SEEK AN ENGINEERS ADVICE REGARDING YOUR PARTICULAR SITUATION.
  2. As a guide only we recommend that you do not bury your tank anymore than 1 metre into the ground.
  3. You must dig your hole 300mm (12″) wider than the base diameter of your tank. If two tanks are to be buried side by side then separate holes must be dug.
  4. Prepare tank base as per our Base Preparation requirements above.
  5. Completely fill tank with water first, then backfill the hole with compacted crusher dust and cement powder. Compact 75-100mm (3-4″) at a time. We also suggest that you erect a fence for safety reasons around the tank. Backfill Ratio = 3 parts crusher dust to 1 part cement powder.

    (So I still suggest ask an engineer!)

 

Edited by shanghailoz
added additional detail
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4 hours ago, Richard Mackay said:

I'm wanting to install a water tank between the house and the street. The house is 2m lower than the street and there is a wall to support the embankment.

Behind the wall is enough space to install the tanks if the ground is excavated. Is it ok to do this and if so can the tanks be buried in this area??

Hmmm... so let me tell you what happens to buried tanks when they are empty, and it rains heavily.

Buoyancy happens!

They rise up out of the ground like spirits from a graveyard on Halloween (topical, see?).

Don't ask me how I know this.
 

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On 2020/10/01 at 10:09 AM, shanghailoz said:

As an update, I contacted a few people on Gumtree that advertise as doing greywater installs.

Zero got back to me.

 

Thats the problem in SA - everyone moans about business being hard, but no-one replies to emails..

I am also looking a grey water system, but something a bit more eco friendly and struggled to find something on the market or someone that does it effectively. 

 

I decided to troll Youtube one evening and came around to this guy who installed a grey water system, not pretty but very clever especially using plants to filter the water and keep that smell down to a min.

 

https://youtu.be/uZXMOfkrZYA

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We implemented 3 systems and have been pleased with the results :)

 

1.  Backup water Municipal water with 1890l storage, pumped to taps for basins, showers, geyser, kitchen and washing machine, with a bypass option if no power or pump fails.

2. 1000l Grey water temporary storage tank, with pump which runs off PV or mains depending on weather / time of day we run it purely used to irrigate the garden.

3. 2 x 5000l and 2 x 1890 l tanks for rain water, used purely for flushing toilets running off a 3-400watt pump which runs off PV or mains depending on time of day used. Also have a first flush diverter and rain strainer to keep debris (Leaves, bugs, twiggs, bird poop) out of the tanks. This system also has a municipal topup bypass for when the tanks run dry and we have to use municipal water.

Our water consumption dropped to 12-14 kl per month from about 21kl per month typically. Also the rain water tanks seem to last us from about mid May2020 to first week of September 2020 for toilet flushing at which point we had to turn on the municipal water to fill one of the tanks to 25% capacity (Float valve installed low in the tank to achieve this. So we don't waste municipal water, once rains begin again this is turned off again :))

 

The only thing I would like to do is increase the rain tanks capacity, so we don't have to switch back to municipal water, before the rains return, provided there is sufficient rains :) worst case in drought conditions the rain tank system would have to use municipal water for toilets.

 

Have also been considering using rain water for the washing machine, probably with a bypass option. As we have seen with the recent rain that the water is a bit dustier than usual, but is expected considering the thanks are just starting to refill with the rain, and the sediments in the tank have probably been stirred up.

 

The only thing I think we are also missing is for the hot water taps, the diverter valve which diverts the initial clean cold water from the pipes, that comes out of ones Hot water taps, and instead of it going down the drain (to our Grey water tanks) it rather goes to our rain water tanks. The additional pipework neededto return to the tank is the problem, chasing into walls etc. so if you are planning and haven't built yet, consider allowing for these extra return pipes ?

 

http://baobabwater.co.za/products/redwater-diverter/

 

https://www.eco3.co.za/red_water_diverter.htm

 

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I started to use my shower water (stand inside 2 plastic buckets while showering) to flush the toilet. The row of buckets next to the toilet became boring, I then decided to build a stand above the cistern to gravity feed water into it. On the stand I put a 68L Rough Tote box with a drain pipe and installed a extra float valve in the cistern. A normal float valve didn't work in this application due to the height difference was only 1m. On the internet I found Brooks Valves makes a high flow low pressure valves for cattle troughs, installed that valve and now the cistern fills within 40sec. I now throw my bucketed shower water and washing machine water into a 210L drum outside and pump it from there into the Rough Tote once a day, to fill the toilet. I used the extra float valve to control the level inside the tote but later had to install a Y type strainer in the supply pipe, because the hair sometimes started to stop the cistern valve from sealing 100%. After a while the water started to smell a bit funky, but now I  just pop a mini chlorine pill (small pill for jacuzzi etc) in the tote and that sorts that for about a month plus. Btw shower water doesn't start to smell fast, but the washing machine water goes funky within 24hrs in the tank. I use the remaing washing machine water or shower water to water the garden. I think this Brooks valve, will work for your rain water to flush toilets in the same setup as mine. In the past 6 months I've never used fresh water to flush a toilet. Once or twice I had to pump water from my rain tank to the toilet supply tank because there was more toilet flushes than showers. As a backup if the tote runs dry, you can just put your hand through the bathroom window and open the ball valve which opens the original municipal water supply to the cistern. Sofar it works 100% for me. My next venture will be to dig a hole for a underground 60L tank so that I don't have to carry buckets through my hose and the put limits on the pump sustem. It is a very rewarding project for me. Enjoy

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Kenton on sea has always had a water shortage

40 years ago the houses had cement tanks with hand pumps

Today its plastic tanks and electric pumps

I have 4 x 10000l and a pump that I run off solar

As the town water used to have a bad taste the toilets were fed from the town and all the rest from the tanks

So I only feed the toilets with town water and filter the water for drinking and cooking, unfiltered for bathing and washing.

Can switch all feeds to municipal or tanks

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An easy solution (but with a moderate cost outlay) is a cartridge filter system (a large industrial size not the small stuff for your RO kitchen system) and a ozone generator and pump for your storage tanks. Try Wassertec for the ozone system, but it costs some bucks! But will last indefinitely as they do commercial systems.

last I looked water tanks for potable water are not permitted due to possible contamination if you have leaks

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On 2020/10/01 at 10:09 AM, shanghailoz said:

As an update, I contacted a few people on Gumtree that advertise as doing greywater installs.

Zero got back to me.

 

Thats the problem in SA - everyone moans about business being hard, but no-one replies to emails..

aint that the truth !

 

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