It’s free and easy to collect: Rainwater. If you use it to water your garden, you can save money. Setting up a rain barrel is not very costly.
Using rainwater to water your garden has some advantages: The water costs nothing. It does not contain minerals, so it does not contain lime, because it has not seeped through layers of rock that are soluble in water. This is because lime-containing water leads to poorer nutrient uptake by some plants. In addition, rainwater can be collected relatively easily if there is a building with a rain gutter. This can also be the covered bicycle parking area of an apartment building.
Connecting the rain barrel to the downpipe
Rainwater is collected in a rain barrel connected to the downspout of a building. Either the pipe has an outlet or is directly connected to the rain barrel. So-called rain collectors can be used for this purpose. These connectors are available for purchase in different models with or without an overflow stop. If you do not want to install a large barrel, you can also connect several rain barrels using a connector made of hose or pipe.
Rain barrels come in a variety of sizes and styles, from simple green barrels to models that look like an antique amphora. The cost varies accordingly – for example, the price in the hardware store for a 300-liter barrel ranges from a good 30 euros to 300 euros.
How is the water taken from the barrel?
Before buying a rain barrel, you should consider how the water is to be extracted. In principle, there are two options. It can be taken out through a faucet installed in the lower part of the barrel, or through the upper opening with the help of a watering can or a pump.
To take out the water through a faucet, the rain barrel should be placed on a pedestal. Some models come with a faucet already attached or are easy to install.
Safety: location and roofing
When installing a rain barrel, make sure that the base is stable enough. Models that are slim and tall should also have an anti-tipper. Open-top barrels need a lid – also as a safety measure for children.
In addition, the type of roofing should be considered: The Federal Environment Agency advises not to collect rainwater for watering if it comes from roofs made of copper or zinc as well as tar paper. These may contain metal compounds and/or biocides.
Cisterns: underground storage for rainwater
Even more effective, but significantly more expensive to purchase, are larger water storage tanks, also called cisterns. These tanks, often underground, are shielded from light and dirt. The temperature of the water in them does not exceed 18 degrees. This is important, otherwise the risk of bacterial contamination increases. However, before the water runs into the cistern, it should be cleaned by a filter.
The capacity of these cisterns or basement tanks is more than 2,000 liters of water, and the right size depends on the annual amount of precipitation. They are usually made of plastic or concrete. In addition to the initial cost of the water storage tank and a pump for water use, there are other costs for installing a cistern, if you do not do it yourself.