Is a rainwater cistern worthwhile for garden irrigation?

Hello,

I wanted to ask if a rainwater cistern is even worthwhile if it is only for garden irrigation.

About our house: All the rainwater is directed through pipes into the garden to the soakaways. (from both sides of the roof and from the garage driveway)

My idea was to install a cistern before the soakaways with an overflow that flows into the soakaways.

We would then use the water for garden irrigation (possibly with an automatic irrigation system)

Can the cistern also be installed by oneself?

Financially, it only pays off after many years/decades – but in detail, it depends on the wastewater costs and the regulations of the respective water authorities/network operators.

Installing it yourself depends on the space and ground conditions.
With plenty of space and not too sandy soil, you can probably do it yourself with a rental excavator (gentle sloping).
With little space and/or sandy soil, I wouldn’t do it, as the risk of collapses (danger to life!) is too high.

I think it's not really worth it for us at least. The problem is that, for example, in summers like this you don't have any water in the cistern when you need it. And even in average summers, such a cistern is empty in a few days, depending on the size and the size of the garden. However, here we can also let the water infiltrate and don't pay any fees. If you have to pay those fees, it might look different. Whether you can install it yourself depends on whether you are able to dig a sufficiently large hole and get rid of the excavated soil. And on how big you want it to be. If you have a lot of space, you can also bury several 1 m3 parts in a row with connections. That can also be done by hand.

We have no wastewater fees because everything flows into the [Rigolen] and seeps away on our property the only saving would be that we do not have to use drinking water for garden irrigation

We don't have any wastewater fees because everything flows into the soakaways and seeps into the ground on our property

the only saving would be that we don't have to use drinking water for garden irrigation

Then you can figure out when it pays off. For example, we have a separate water meter for garden water and pay €1.60 per m3. Then calculate those costs against the costs of the cistern and the pump electricity. And keep in mind that you still need household water in summers like this one. The most economical option is always your own well, if it can be realized at a reasonable depth.

A cistern can also be worthwhile for other reasons, as some plants do not like hard water and the tap water or groundwater is usually harder than rainwater. My wife is constantly nagging me to finally connect the cistern (it is already buried) or at least set up a rain barrel. But she also wanted a fence and trees before we moved in.