Is rain water storage really worth it in GP?

I’ve been thinking about the economics behind rain water storage primarily intended for irrigation.

Gauteng gets plenty rain threw summer, so filling a 5 kl Jojo is pretty easy even if your catchment area isn’t that big.
Now since we get plenty rain, we don’t use much water for irrigation during the rain season, just look at your water bill summer vs winter.

Come end of the rain season you have a full Jojo, but how long will that water last on a house with a big garden, a week, less, maybe a bit more?
So now your Jojo is empty and it will only rain again in 6 months, this is the 6 months in which you actually need irrigation water for your garden since it rains for the other 6 months of the year.

Simple answer is get more tanks to carry you threw winter, yes sure but at R5k a pop. How much municipal water can you buy for R5k, or pump for R5k if you have a borehole?
Plus remember the R5k only buys you a 5 kl tank which only adds a week and you ideally want 6 months worth of water, so you need 120 kl of storage, that’s R120,000 just for tanks, then you need the space, the pumps etc.

Is my thinking correct if I say catching rain water for later use doesn’t make economic sense at all, that people just do it to feel good about themselves, that they are saving water or saving the planet whatever?
There is of course also the emergency factor, if the taps run dry, but again, how far will 5 kl of water really get you if the brown stuff really hits the fan?

Even at R50 per cubic meter or kiloliter if you prefer (my top end is around R30), A 5kl Jojo is worth R250. It will take 20 rainy seasons to pay for the tank, nevermind anything else.

If you only do it for a specific use case, it could make more sense. For example, I need to put about a thousand liters into my pool every two weeks or so. So a 5000 liter tank would substantially reduce my reliance on municipal water to keep the pool full. But still, at R50 a pop… it remains a feel good proposition, not a financial one.

That’s why I have 1000 liters for emergency purposes, and a submersible pump to extract water from the pool should the outage last more than two days. I keep separate supplies of drinking water, I have a water cooler and I refill the bottles at R30 at a local shop.

If the outage exceeds a week, I would probably relocate to a better location for the duration of the outage.


If you want to do your full garden from tanks, then is GP is is not worth it. You need more constant rain to keep the tanks filled so that you can water in between the rains. That is not how GP weather works.

Now if you only had a few vegies in a small patch then it is a different matter and you can get quite far wit a tank. But for keeping your lawn green during winter it’s a no.

It will most probably never make sense in Rand and cents, unless you have a swimming pool. But BOY, do the water comes in handy.

We when we had the drought in Cape Town, Day Zero round the corner, We installed JoJo tanks. Luckily, we never had to use them for that.
We now use it for washing clothes and flushing the toilet. It was also very handy when our Water meter broke and we was without water for 4 days.
Let me tell you, no amount of money can make up if the wife and kids starts to through tantrums because of no water.

Best money ever spend!!! :slight_smile:

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Amen brother. I swear, I don’t need a welding machine. I just have to leave the wife without water for half a day, and with a bit of suitable cabling that makes a perfectly good welding machine…

The sums I did during #DayZero - JUST for water, no pumps or anything.

House was running on 5kl per month x 12 month = 60kl

For that I need about 10 tanks as for in winter I need less … depending on the winter obviously.

A 5kl tank at the time costed me R3850 x 10 = R 38 500 for just the tanks.

We paid about ±R450 per month for water, yeah, I complained = ±R 5400 per year.

In ±7 years the tanks would have been “paid”. No Municipal water used.

To put 10 x 5kl tanks on the property … NO! :slight_smile:

Ps. Did look at a 1 x 50kl tank. :laughing:

A month before Day Zero, due to CoCT dropped the water pressure in our area,enough that we had no water in the taps and we were reduced to getting buckets from the swimming pool, for three days, luckily the severe pressure situation was reversed, so I fell for the Day Zero scare, hook line and sinker and put in tanks and a pump, etc, which was never really used after that

Agreed with most here.

Taking just from rain water does not seem a viable financial solution. If its to just tide you over during no water, then the convenience factor is well worth it. Similar to a backup battery only backup system where payback is not a consideration.

Fortunately I have potable water less than 4m underground and I am off grid where water is concerned. I spent R10k to install and maintain the system over the past 3 years and extracted over 1 380kl. That’s over 1 380 000 litres in 3 years worth over R89k going at CoCT water tariffs from 2 years ago.

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