First of all, you need to ask yourself where the best place to collect rainwater is. The solutions presented here are extremely varied and depend on local conditions.
The classic – a water butt
The classic solution here is of course a water butt. Back in the day, our grandparents collected water like this from rainfall on garage or shed roofs. Plastic water butts are readily available from hardware stores for just a few euros and can be set up quickly. There are several different options for removing the rainwater from them. If the butt is slightly elevated, the water can be easily removed from a closable drain just above the ground. However, if the water has to be transported over a longer distance, you'll need a barrel pump. This is placed in the barrel, connected to the mains and a garden hose can then be connected above the water surface. This is a practical system, but one which is limited due to the small volume a water butt can hold. If you want to water your lawn with this method, you will quickly find yourself in front of an empty barrel and have to resort to tap water. But using a water butt is well worth a look if you have a smaller garden with just a few plants that need to be watered.
The exclusive – the cistern
Cisterns can be used both above and below ground. They are available with volumes of around a thousand litres up to several tens of thousands of litres and are usually made of concrete or plastic. Concrete cisterns are generally sunk into the ground during the construction of a house and this is difficult to do later without the use of heavy machinery such as excavators and cranes. If you're thinking of building a home in the future, you should consider a cistern, especially as this means that a separate water cycle, the toilet flush and the washing machine can be operated with rainwater. This not only protects the environment, but also your wallet.
Plastic cisterns that are installed subsequently are superficially embedded in the ground. Depending on the selected size, it may also be feasible to install one with a spade and shovel. Water has to be removed from cisterns by means of domestic waterworks. Domestic waterworks consist of an electric water pump, which detects and regulates the water pressure via sensors. Domestic waterworks should be installed in a frost-free area and will get to work almost unnoticed. As soon as a tap is turned on, the domestic water works start up and pump rainwater from the cistern into the pipe. Due to its large volume, the cistern is suitable for dissipating all rainwater from the house roof into it.
DIY: The IBC container
The hybrid system of rain barrel and cistern presents itself in the "DIY version" of the Intermediate Bulk Container, usually known as an IBC container. Actually intended for the transport of liquids, these containers are increasingly being used in domestic gardens. Due to their compact dimensions of approx. 1x1x1 metres for the standard version, IBC containers fit on a conventional Euro pallet and can therefore be transported on a trailer. IBC containers can be purchased from local waste management or construction companies for under 50 euros.
When covered by taller plants, this container is barely noticeable in the corner of the garden.
Domestic waterworks, garden pumps or standard submersible pumps can all be used for the removal of water here. Each of these pumps provides sufficient water pressure to use a lawn sprinkler or water hose.
How does the water get into the container?
The simplest, and above all most effective way to collect rainwater is to use roof surfaces. Depending on the selected container and the corresponding volume, garage, shed or whole house roofs are suitable. Using a water strainer, a water separator that is mounted in the downpipe, this works completely automatically. If the container is full, the excess water is drained through the original path of the downpipe.
A water strainer can be retrofitted by anyone in the downpipe.
You want more information about watering your plants? Then part 2 of our guide might be just right for you.