How Long Can You Store Rainwater For Plants?

Switching to using rainwater for your plants is both an eco-friendly and also cost-effective idea.

Not only that, but rainwater is also much better for your plants compared to tap water, which has additives that make it safe for human consumption, although not ideal for plants.

If you’re considering making the switch from tap to rainwater, you may be wondering how exactly to go about the process of collecting and storing said water.

In this article, we’ll go over the ins and outs of collecting and storing rainwater.

How Long Can You Store Rainwater For Plants?The answer to this question isn’t so simple, as it can heavily vary depending on the method of storage and whether or not you have a filtration system. If left sitting just in the collection barrel, it can still be used to water for many months as long as there are no contaminants inside and it doesn’t go stagnant.

Things like mosquito larvae or bird droppings can contaminate the water, although there are multiple ways to prevent things like this from happening.

Mosquito dunks can eliminate the bug problem, and placing a screen over the opening can help prevent debris from going into the tank. Doing little things like that can significantly increase your rainwater’s shelf-life from a few months to a year or more. At some point, it’s a good idea to give the tank a good cleaning to prevent the buildup of bacteria and algae.

If the rainwater is only for plants and not human consumption, you can be a lot more lenient with your cleaning and storage rules; plants will generally be unbothered by the collected rainwater unless it’s gone stagnant.

Ways To Collect Rainwater

Rain Barrel:

By far the most common way of collecting rainwater is by using a rain barrel, which sits at the bottom of a gutter downspout. When it rains, the water will pour out of the spout and collect into the bucket. This method is very simple and easy to acquire and set up, making it popular for those just starting out.

The barrel will generally be around 50 to 100 gallons, so while this method isn’t the best if you’d like to collect water on a larger scale, it’s great for those just looking to water their personal gardens or plants.

Watch the video below to understand the difference between wet and dry system.

Wet System:

To use this method, you have to find the collection pipe underground and connect to downspouts from other gutters. The rainwater fills the underground piping; then, the water rises in the several pipes until it goes into the tank.

With this system, the tank will be much larger than the rain barrel, so it will allow for rainwater collection on a much larger scale.

Dry System:

The dry system is a different version of the rain barrel layout but with a larger volume that can be stored.

The top of the tank sits below the bottom of a gutter downspout, and the water pours in that way, although since the barrel is much larger, it can hold a larger amount of water.


Collecting rainwater for your plants is something both you and they will benefit from. Not only do they prefer rainwater over tap water, but your water bill will also be lowered from not using gallons on plants.

Collecting rainwater—especially on a smaller scale—is cheap and easy to do, and as long as the water doesn’t go stagnant, it can be stored almost indefinitely.

It’s never too late to make the switch to using rainwater—your wallet and plants will thank you for it too!

Also read

Does Rain Make Grass Grow Faster?

How Much Water Per Gallon of Soil

How to Get Rid of Worms in Potted Plants ( Easy Method )

What is the Difference Between Soil and Dirt?

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