Home Crochet baby clothesUse rainwater for toilet and washing machine: 10 tips

Use rainwater for toilet and washing machine: 10 tips

  • Rainwater as process water
    • Rainwater for toilet
    • Rainwater for washing machine
    • Rainwater for toilet and washing machine

Rainwater is a classic in the garden, which is not only suitable for watering plants. The collected water can also be used in the household and provides an environmentally friendly alternative to traditional tap water. For this reason, many want to switch to the rainwater for toilet and washing machine. How this works, you will learn here.

If you want to effectively use your collected rainwater, you need not just limit yourself to watering your plants. Rainwater can also be used in the household with some preparation, which is an interesting alternative to conventional water supply for many people today. Especially homeowners with a large plot can collect a lot of rainwater for the washing machine and toilet. However, there are some points to consider before using them, because you can not just set up a ton and use that rainwater for your toilet or washing machine.

Rainwater as process water

If you want to use collected rain as process water, you have to pay attention to a few things. Compared to using rainwater for casting, this project requires you to be aware of certain conditions in order to be able to use the liquid collected in the long term.

If you deliver your garden with rain barrels, you will be able to collect a large amount of water, but in most cases this will not be enough for the desired application. For this reason, there are some important points to make sure that you can use the rainwater as effectively as possible.


Use rainwater for the toilet or washing machine is only possible if you have a cistern in which this can collect. Yes, a cistern is nothing but an oversized rain barrel . This is located in the ground and is connected via lines with the water cycle of your house. The rainwater cistern is an important part of the rainwater harvesting system and requires appropriate dimensions and a good placement to effectively absorb and store leachate.

safety device

The fuse ensures that rainwater in the water cycle does not mix with drinking water and contaminate it. Since rain is leachate, many bacteria and dirt particles get into it, which could negatively affect your health. The backup prevents this problem. It is even legally required by the Drinking Water Ordinance. If, for whatever reason, you do not integrate them into your planning, you may be required to pay heavy fines and a subsequent security.


The rainwater systems require annual maintenance by a specialist or yourself, if you have sufficient knowledge in this area. In these, all important aspects of the system are checked to ensure the function and safety. Above all, the hygiene of the system is checked during maintenance, so you can use the rainwater for the washing machine without any concerns.


You should consider carefully whether you want to install a rainwater harvesting system, because not every house is suitable for it. The reason is the material of the roofing. There are materials that contain substances that should not get into the water for the washing machine.

This includes:

  • copper
  • zinc
  • lead

These substances get into the water and are therefore not recommended for use in the home. Even the plant is powerless with these substances. Since this is leachate from the roof, this problem can only be solved if you replace the roof covering and use materials that are free of these materials.


In addition to roofing, you should also pay attention to the environment in which you live. This is important if you can use rainwater because of the impact of man and nature on the quality of the rain . So it is not recommended to use rainwater for your washing machine if you have the following nearby.

  • industrial areas
  • farmed yards
  • power plants
  • Mining
  • Parking lots and parking garages
  • highways


Numerous pollutants can pollute the water, which makes the use of rainwater not ideal . After all, these can get into the wastewater after use, which can definitely lead to higher wastewater charges for you.

Clayed floors

In addition to the points mentioned so far, it should also be noted that soils with high clay are only partially suitable for the use of a cistern. Clay-rich soils are so impermeable that the water in the soil stores and seep only small amounts. As you can see, you have to consider all these points when implementing a rainwater system in order to be able to incorporate them effectively into your everyday life. For this reason, it is advisable here to ask a specialist for help.

Tip: In order to be able to differentiate the drinking water from the rainwater pipes, they have to stand out in color. This means it is easy to identify which pipes need to be checked during maintenance.

Rainwater for toilet


If you want to use rainwater for the toilet, you do not have to pay attention to the water quality. Since this water is used exclusively for rinsing after using the toilet and thus does not come into contact with humans, there are no health concerns . The only thing to watch out for is the size of the cistern.

The average water consumption of a toilet is as follows:

  • Rinse: about 6 liters
  • 10 rinses daily: 60 liters

These are only averages for a typical family. However, these values ​​can be significantly higher. So plan what is the possible, daily consumption, so you do not have to do without rinsing water on dry days.

Rainwater for washing machine


If you use rainwater for the washing machine, you must first of all pay attention to the possible stress due to bacteria . There is no problem in itself if you use the rainwater to wash your laundry with. Since rainwater is lime-free, 20 to 60 percent less detergent is needed per wash, as lime acts against the substances contained in the detergent. The following tips will also help you in using the rainwater.

1. If you have people with disabilities, such as the elderly, children, the sick or people with a weak immune system in the household, you should not use rainwater to wash your clothes. Although the water is heated during washing, the last rinses are usually with cool water. This increases the risk of transmission of bacteria when wearing the clothes.

2. Use good filters to get as many germs and bacteria out of the water as possible. The more effective the filters, the cleaner the rainwater for the washing machine.

3. Iron the laundry after washing . This allows the already mentioned problem to be handled well.

Tip: A big advantage of a cistern for the storage of rainwater is the lack of light and the cool temperatures. These counteract the formation of algae and germs that could otherwise get into the wash water.

Rainwater for toilet and washing machine

Rainwater for toilet and washing machine: is it worth it ">

1. Acquisition costs: With the acquisition costs you have to expect even for small cisterns with approximately 2.500 to 6.000 euro. Of course, you can push the price when you lend a hand, but some aspects of the installation must be done by a specialist . These services include storage, piping and more.

2. Annual water savings: The consumption of drinking water over the year is between 40 and 60 cubic meters due to the use of a rainwater harvesting system. If, above all, the washing machine with the collected rain is used, significantly more cubic meters can be saved . These values ​​correspond to a household with four people who, on average, wash their clothes frequently and visit the restroom.

This allows the following cost savings in the year:

  • without waste water charges: 250 to 350 euros
  • with sewage fees: 150 to 250 euros

Depending on the incorporation of rainwater into everyday life, you can replace correspondingly high amounts of water and thereby save.

3. Maintenance: You should leave the maintenance of the cistern and system to a specialist if you yourself have no knowledge in this area. In the year hereby about 100 euros further costs await you. The final amount varies from state to state. Further maintenance costs will be charged if special water meters have to be installed and calibrated regularly.

payback period

As you can see, when you start to use it, you will spend quite a lot of money to realize the project and then pay for it every year. Only then can the system function effectively. On average, the so-called payback period is at least ten years, which is only worthwhile considering the long-term use of rainwater in the home.

Otherwise, you should refrain from installing a system. Rainwater harvesting systems are especially recommended if a property is to be provided with new lines or the washing machine is in the basement. If you have an old toilet, the savings are much lower.

Tip: The purchase of a rainwater harvesting system is particularly effective if you live in rainy regions, which means you can use significantly more rainwater instead of drinking water. These include, for example, the Saarland, the Allgäu and many of the port cities such as Hamburg or Kiel, which get much more precipitation than other regions due to their proximity to the water.

Knitting herringbone pattern - monochrome and bicolor
Descale the washing machine - how often and with what?