Tips on How to Filter Rainwater in a Barrel

Rainwater is an abundant natural resource that can easily be harvested provided you have the right equipment and the proper technique on how to filter rainwater in a barrel. 

Here’s what you need to know:

There are many ways to filter rainwater in a barrel. You can use natural filters, such as charcoal, stones & sand, placed inside the barrels where the rainwater flows. But, a better way uses multiple barrels, with the largest barrel collecting under the gutters, and then dripping into a series of smaller barrels.

But there’s a lot more to know about rainwater harvesting, water filtration, and the laws some states in the US have around rainwater harvesting, so let’s keep reading!

Challenges for rainwater harvesting

The main challenges in rainwater harvesting are how to filter and store rainwater properly to make it useful for everyday uses.

Rainwater that is filtered and stored can be used for watering the garden, cleaning the yard, plumbing, cooking, and in some cases, even for drinking.

So what equipment do you need to filter and store rainwater?

Basic Equipment for rainwater harvesting

Your basic equipment in rainwater harvesting will be a reliable water tank to store your rainwater and a barrel or several barrels that you will need to collect and filter the rainwater.

You need to know the proper technique on how to filter rainwater to make sure it is clean and free of waterborne contaminants or dirt that might be harmful to you.

This means you have to set up your equipment.

To break this down further, here is the basic equipment that you will need for rainwater harvesting:

  • barrels
  • PVC pipes
  • water tank
  • others (tap, a piece of cloth, a fine net, etc)

Laws You Need to Know on Rainwater Harvesting

Before you start rainwater harvesting, there are certain laws that might be applicable to you, depending on where you live in the United States.

Basically, these laws dictate how many barrels of rainwater you can collect. For instance, Oregon might have different laws from say, Utah or Nevada.

In Utah, you cannot just go place rainwater barrels because there are is a ban on rainwater collection in the state.

Interestingly, Texas and Ohio “allow rainwater harvesting for potable purposes.”

Did you know that in Nevada, the state government does not authorize the collection of rainwater using barrels?

Using a Barrel for Rainwater Harvesting

You often see people using barrels to “catch” or harvest rainwater. These barrels are often placed in the corners of houses, barns, and sheds.

Barrels are placed directly below large plastic PVC pipes (downspouts) running down corners and gutters of houses so that rainwater go directly to the barrel instead of through underground pipes or directly to the ground.

A piece of cloth or a fine net is often placed on top of the barrel. This often serves as the first filter, trapping leaves and preventing other debris from falling directly to the barrel.

Barrels for rainwater harvesting may vary in size depending on your need. But aside from collecting rainwater, you can also use the barrels to filter rainwater.

Do I need to filter rainwater?

Yes! So how do you filter rainwater in a barrel?

There are a lot of ways to filter rainwater in a barrel. The most common is using natural filters, such as charcoal, stones, and sand. These natural materials are placed inside the barrels where the rainwater flows.

Usually, there is a separate layer of sand, followed by a layer of stone or gravel, and finally a layer of charcoal inside the barrel. Rainwater passes through these several layers before flowing out of a tap that is often installed near the bottom of the barrel.

Essentially, the natural materials filter the rainwater before the rainwater flows out of the barrel.

The materials provide a natural barrier to trap dirt and other undesirable materials that are still in the rainwater.

The simplest way is to place sand, charcoal, and stone layers in a single barrel which is fitted with a tap.

Using Multiple Barrels to Filter Rainwater

However, a better way is to use multiple barrels placed strategically, so that the first and most probably biggest barrel is placed directly under the pipes to collect rainwater.

This first pipe has an overflow pipe which is directly connected to the second barrel.

The difference between the first and second barrels is that the second barrels have the layers of sand, stone, and charcoal to filter the rainwater.

For further filtration, numerous barrels are often lined up so that the rainwater can pass through multiple cycles of filtering.

What you need to keep in mind is the location of the barrels such that the first barrel is a little higher than the second barrel, the second barrel is higher than the third barrel, and so on and so forth.

How do I purify my drinking water tank?

After you have filtered rainwater using barrels, it is recommended that you either boil or treat the filtered water to make sure that it is potable.

The recommended ways include boiling the filtered water or using chemicals such as chlorine to treat the water. For chemical treatment, there are recommended steps in using chlorine to treat the rainwater that you have collected.

Using a Reliable Water Tank to Store Clean Water

After you have filtered rainwater, the next step is to store the clean water. This is where having a reliable water tank becomes important.

It is not just a matter of choosing any tank. There are several water tanks that you can choose from, it is just a matter of knowing which water tank will best suit your needs.

How do you choose which tank to use?

Atanistank Can Help You!

If you want to spend less time thinking about which water tank to use for what purpose, then it might be better if you go directly to a water tank and septic tank specialist, such as Atanistank.

We are a professional manufacturer of water tanks at Atanistank, and we have the right water tanks to suit your every need.

Atanistank rainwater tanks come in different shapes and sizes including the following:

  • rainwater collection tanks
  • rainwater harvesting tank
  • steel rainwater tanks
  • plastic rainwater tanks
  • small rainwater tanks
  • large rainwater tanks
  • rectangular rainwater tanks
  • domestic rainwater tanks
  • round rainwater tanks

These water tanks are all specially designed and manufactured to store your precious resource, such as clean water.


Rainwater harvesting is a worthwhile effort. Rainwater that you have collected can be used for many purposes, and in some cases, rainwater can be a lifesaver, particularly in areas where is there is drought.

It is just a matter of having the right tools such as water tanks and barrels and knowing the right techniques to do it. Seeking the help of experts, such as Atanistank, is also highly recommend.

Jeff Campbell

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