How to Store Rainwater for Indoor Plants: Tips for Collecting and Storing without Contamination

how to store rainwater for indoor plants

Last Updated on October 2, 2023

Most people know that plants need water to survive. But what many don’t realize is that not all water is created equal. In fact, rainwater is often better for plants than tap water.

Rainwater is naturally soft, which means that it contains fewer minerals than hard water. This can be beneficial for plants because it reduces the risk of mineral buildup, which can damage roots and hinder growth.

Rainwater is rich in nitrogen and other nutrients that help promote healthy plant growth. You should consider watering your indoor plants with rainwater rather than tap water if you want to give them a boost.

Rainwater is a natural, nutrient-rich source ideal for indoor plants. Unlike tap water, it’s soft, minimizing mineral buildup that can harm plant roots. To harness its benefits, collect rainwater using methods like barrels, then filter out impurities using tools like cheesecloth. Store in food-grade containers in cool, dark areas, ensuring its use within six months for optimal plant health.

If you want to take advantage of this natural resource, there are a few things you need to know about storage and usage. Let’s take a look at some tips on how to store rainwater without contaminating it.

Why Rainwater is Better for Plants than Tap Water?

Compared to hard water, rainwater contains fewer minerals because it is naturally soft. Plant growth can be inhibited by mineral buildup, which damages roots.

Mineral ingredients of rainwater are also more easily taken up by plant roots since the water has already been through the process of weathering. The contents include a small amount of nitrogen, phosphorus, potassium, and other minerals which are necessary for healthy plant growth.

Nitrogen Helps with the Growth of Leaves

One of the most important nutrients found in water is nitrogen. Nitrogen helps to promote the growth of leaves, making them larger and more robust.

Nitrogen helps to prevent the formation of yellowing or brown spots on leaves. As a result, rainwater can play an important role in the health of your plants.

Phosphorus Helps with the Growth of Roots and Flowers

Phosphorus is an essential element for plant growth, and it can be found in rainwater. This nutrient helps to promote root and flower development, and it also helps plants to resist disease.

Phosphorus plays a role in soil fertility, making it an important component of any gardening or agriculture operation. While phosphorus can be found in many different fertilizers, rainwater is a free and easy way to get this important nutrient to your plants.

Potassium Helps with the Overall Health of the Plant

Potassium helps to regulate water uptake, photosynthesis, and enzyme activity. In addition, potassium is involved in the movement of carbohydrates and other molecules within the plant cell.

As a result, rainwater helps to ensure that plants are healthy and able to grow properly. While all plants need potassium, it is especially important for fruit and vegetable crops. Potassium helps to improve flavor and color, and it also increases the shelf life of fruits and vegetables.

Other Minerals

Rainwater contains other important minerals like magnesium, calcium, and sulfur.

  • Magnesium helps with the development of chlorophyll, which is essential for photosynthesis.
  • Calcium helps with the growth of cell walls and strengthens plant stems.
  • Sulfur helps with the production of enzymes and other proteins.

All of these minerals are essential for healthy plant growth, making rainwater an excellent choice for watering your plants.

How Can You Collect Rainwater?

Buckets or Barrels

Buckets or Barrels

There are a few different ways to collect rainwater. One of the simplest methods is to set out buckets or barrels to catch the water as it falls from the sky.

If you live in an area with frequent rainfall, you may want to consider installing a rain barrel. A rain barrel is a large container that is placed under a gutter downspout. As rain falls, it is funneled into the barrel, where it can be stored for later use.

Rain barrels typically have a spigot near the bottom, which makes it easy to fill buckets or watering cans. Some also have overflow valves, which allow excess water to be released so that the barrel doesn’t overflow. Rain barrels are available for purchase at most home and garden stores.

Gutter Diverter

Gutter Diverter

Another option is to collect water from your gutters. You can do this by installing a gutter diverter, which directs the flow of water from your gutters into a barrel or container.

You can also add a screen over the top of the container to keep out leaves and other debris. Be sure to position the barrel on a level surface so that it doesn’t tip over, and consider attaching it to your house for additional stability.

Downspout Extension

Downspout Extension

If you don’t want to install a gutter diverter, you can simply attach a downspout extension to your gutters. This will direct the flow of water away from your foundation and into a container or rain barrel.

Downspout extensions are available at most home and garden stores, and they are relatively easy to install.

Once you have collected the rainwater, it is important to store it properly to prevent contamination.

How to Filter Rainwater?

As anyone who has ever been caught in a downpour knows, rainwater can be extremely dirty. Not only is it full of dirt and debris, but it can also contain harmful bacteria and viruses.

There are a few different ways to filter rainwater, and the most effective method will depend on the amount of water you need to filter and the quality of the water.

Cheese Cloth

One of the simplest ways to filter rainwater is to use cheesecloth. Cheesecloth is a type of cloth that is made from cotton or linen and has a very tight weave.

To use cheesecloth to filter rainwater, simply drape it over a container, and pour the water through it. The cheesecloth will catch any debris, and the water will be filtered.

You can also use cheesecloth to strain water that has been sitting for a while and has become stagnant.

Coffee Filter

Another easy way to filter rainwater is to use a coffee filter. Coffee filters are designed to remove coffee grounds from water, so they will also remove any debris from rainwater.

To use a coffee filter to filter rainwater, simply pour the water through the filter. The filter will catch any debris, and the water will be filtered.


A pre-filter is a type of filter that is used to remove large particles from water. Pre-filters are typically made of charcoal, which helps to remove impurities and odors from the water.

Pre-filters are often used in conjunction with other types of filters, such as reverse osmosis systems, to provide clean, safe drinking water.

Activated Carbon filter

Activated carbon filters are typically used in water filtration systems to remove impurities from the water. The process by which they work is known as adsorption, whereby molecules of the impurity are attracted to the surface of the activated carbon filter and held there.

Activated carbon filters are highly effective at removing a range of impurities, including chlorine, bacteria, and pesticides. They are also relatively low-maintenance, making them a popular choice for home water filtration systems. However, it should be noted that activated carbon filters will eventually need to be replaced, as they become saturated with impurities over time.

UV Filter

UV filters work by using ultraviolet light to kill bacteria and viruses. The water is exposed to UV light for a specific amount of time, which kills the microbes without harming the water itself.

This makes it safe to drink or use for other purposes. In addition, UV filters can also help to remove sediment and other particles from the water, making it even cleaner. Installing a UV filter is an easy way to make sure that your rainwater is safe to use.

You can also let the water sit for 24 hours so that any sediment will settle to the bottom of the container.

How to Store Rainwater for Indoor Plants?

Rainwater can be stored in a variety of different containers, including barrels, buckets, and jugs. However, it is important to take steps to reduce the contamination.

One way to do this is to use food-grade containers. Food-grade containers are made of materials that are safe for storing food and water. They are also designed to be airtight, which helps to prevent contamination.

Another way to reduce the contamination is to clean the containers before using them. You can do this by scrubbing them with soap and water, or by using a diluted bleach solution. Once the containers are clean, be sure to rinse them thoroughly with clean water.

Store the filtered water in those clean containers.

Here are some tips to keep the rainwater fresh:

  • Store the rainwater in a cool and dark place. This slows down evaporation and prevents the growth of unwanted organisms like bacteria and algae. It also keeps the water from becoming stagnant.
  • Regularly clean your rain barrels or storage tanks. This will help to ensure that the water you collect is safe for your plants and lawn. The key is to keep the water clean and free of contaminants to store for long-term use.
  • Use the stored rainwater within six months for the best results.

Where to Store Rainwater?

The best place to store rainwater is in a clean, covered container. This will keep out debris and insects. You can also add a small amount of bleach to the water to help prevent the growth of bacteria. Be sure to use food-grade bleach, and only add a few drops per gallon of water.

Another option is to store the rainwater in a large, covered container with a spigot. This will allow you to easily dispense the water without having to lift the heavy container.

If you live in an area that is prone to flooding, you may want to consider storing the rainwater in an above-ground tank. This will protect it from contamination.

Rain Barrel

Rain Barrel

A rain barrel is a type of container that is specifically designed to collect and store rainwater. Rain barrels typically have a capacity of 50 to 60 gallons, making them a good choice for small-scale water storage.

Rain barrels are often made of plastic or metal, and they have a spigot near the bottom so that you can easily dispense the water.

Some rain barrels also have an overflow valve, which allows you to connect multiple barrels together. This is a good option if you live in an area with a lot of rainfall and you want to be able to store more water.

Underground Storage Tank

Under-ground Storage Tank

An underground storage tank (UST) is a type of container that is buried beneath the ground. USTs are typically made of metal or concrete, and they can range in size from 50 to 10,000 gallons.

By storing rainwater underground, it stays cooler and is less likely to evaporate. Also, an underground storage tank can be easily connected to an irrigation system, making it easy to keep your garden watered during the hot summer months.

USTs are a good option for storing large amounts of water, but they can be more expensive than other options. In addition, USTs must be properly installed and maintained to avoid contamination.

Plastic Drum

Plastic Drum

A plastic drum is a type of container that can be used to store rainwater. Plastic drums typically have a capacity of 55 gallons, making them a good choice for small-scale water storage.

Plastic drums are often made of high-density polyethylene (HDPE), which is a durable material that is resistant to chemicals and UV radiation.

Plastic drums are a good choice for storing rainwater because they are lightweight and easy to move. In addition, HDPE is a food-grade material, which means it is safe for storing drinking water.

However, plastic drums can leach chemicals into the water if they are not made of food-grade HDPE. In addition, plastic drums are not as durable as metal or concrete containers, and they can break if they are dropped or hit by a heavy object.

Tips for Using Stored Rainwater Effectively on Indoor Plants

Once you have collected and stored rainwater, there are a few things you can do to make sure it is used effectively on your indoor plants.

  1. Be sure to water your plants early in the day. This will allow the water to soak into the roots before the heat of the day evaporates.
  2. Water the soil, not the leaves. Leaves can burn if they are directly exposed to the sun after being watered.
  3. Use a watering can or hose with a fine nozzle or a shut-off valve so you can control the flow of water to avoid disturbing the roots of your plants.
  4. Apply water slowly and evenly so that it has time to soak into the soil.

It is important to note that rainwater can also contain pollutants from the atmosphere, so it is important to test the pH of the water before using it on your plants.

In general, rainwater is a good option for watering plants, but it is important to use it in moderation. When possible, water your plants with filtered or distilled water to minimize the risk of exposure to potentially harmful substances.

By following these tips, you can be sure that your indoor plants are getting the most out of the rainwater you provide.


How Often Should I Water My Plants With Rainwater?

There is no definitive answer to how often you should water your plants with rainwater. It depends on a variety of factors, including the type of plant, the size of the pot, the climate, and the time of year.  

In general, most plants need about 1 inch of water per week. If it’s been raining a lot, you may not need to water your plants as often. On the other hand, if it’s been dry and hot, your plants may need more water. Pay attention to the condition of your plants and adjust accordingly.

What Are Some Common Pollutants Found in Rainwater?

Rainwater can pick up pollutants from the atmosphere and deposit them on the ground. Some of the most common pollutants found in rainwater include dust, soot, and chemicals.

  • Dust often contains harmful heavy metals like lead and mercury, which can contaminate groundwater supplies.
  • Soot is another common pollutant that can come from both natural and man-made sources, such as forest fires and car exhaust.
  • Chemicals are also frequently found in rainwater, particularly in urban areas where they can be released into the air from factories and automobiles.

While some of these pollutants are short-lived, others can linger in the environment for years, potentially causing long-term damage to ecosystems.

What Should I Do if I Notice a Change in My Plant’s Appearance After Watering With Rainwater?

If you notice a change in your plant’s appearance after watering with rainwater, it is best to stop using rainwater and switch to another type of water. Also, flush the roots with clean water to remove any residual chemicals. This is especially true if you notice any sign of distress, such as wilting or discoloration.

It is also a good idea to test the pH of the rainwater before using it on your plants. This will help you determine if the water is too acidic or alkaline for your plants.

Finally, be sure to check for signs of pollutants in the water, such as dirt or oil. If you notice any of these things, it is best to dilute the water before using it on your plants.

How Can I Tell if the Rainwater is Safe For My Plants?

One way to tell if the rainwater is safe for your plants is to test the pH of the water. You can also look for signs of pollutants, such as dirt or oil, in the water. If you notice any of these things, it is best to dilute the water before using it on your plants or switch to another type of water.

Can I Use Rainwater on All of My Plants?

No, not all plants can tolerate rainwater. Some plants, such as succulents and cacti, prefer water that is high in minerals. Others, such as orchids and ferns, prefer distilled or filtered water.

It is best to do some research on the specific needs of your plants before watering them with rainwater.


One of the best ways to conserve water is to collect and store rainwater. Not only does this help to reduce your water bill, but it also provides a ready source of nutrient-rich water for your plants during drought conditions.

However, rainwater can also be a breeding ground for bacteria and algae if it is not stored properly. To prevent the growth of these organisms, it is important to store rainwater carefully to get the most out of it. By following these simple guidelines, you can ensure that your plants will thrive using this valuable resource.

Hope that can help you to understand how to store rainwater for indoor plants. Do not forget to check the condition of your plants regularly and water them accordingly. Thanks for reading!

How to Store Rainwater for Indoor Plants: Tips for Collecting and Storing without Contamination

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