How to Make a Rain Barrel

Rain Barrels are these days, becoming very popular with gardeners as they come to realise the benefits of using rainwater in their garden as opposed to tap water.

One important fact about rain barrels is that they can fill quite quickly with rainwater and then overflow, so in some respects they aren’t the most efficient way to collect and store rainwater but it also does have quite a bit to do with the downspout diverter as well. There are some things you can do though to make rain barrels more efficient.


Tips for Making Your Own Rain Barrel

Recently I made my own rain barrels and discovered some important basics on how to make your own rain barrel that I felt other designs were lacking, so I’ve decided to go ahead and share them with you here today. Some of these things are fairly basic but it may also surprise you that they are important points that are commonly overlooked.

Considering the Rain Barrel Overflow 

One of the things I’ve discovered is that many rain barrels have overflows on the side. Quite often these overflows are a large diameter to match the size of the inlet. This is done so that water going out through the overflow can match the water coming in through the inlet. The problem with attaching your overflow to the side of your rain barrel is that it will decrease the amount of rainwater you can store by up to 10%.

So when you make your own rain barrel, make sure you place the overflow above the level of the top of the rain barrel and the inlet above the top of the overflow. That way you can maximise the amount of rainwater you can collect.

Another important point to consider when you make your own rain barrel is where you divert the rainwater from the overflow. Many rain barrel installations just direct the overflow back into the storm water system or straight onto the ground not far from the base of the rain barrel. This to me is just a waste of precious rainwater.

I’ve found that it is possible to divert the rainwater from your overflow directly to your garden. This fits with what most gardeners already know. Deep watering is much better than shallow watering. So when it rains and your rain barrel overflows, your plants get a much deeper watering.

The important thing to remember with this procedure is that you should set it up so that in times when you are getting lots of rainfall you can still divert that overflow back to the stormwater if need be.

How to Make a Rain Barrel

Where to Place the Rain Barrel Outlet?

When I made my own rain barrels I also applied the above theory to the outlets. Therefore placing the outlets on the bottom allowed me to access all the rainwater stored within the rain barrel. I also connected the outlets in series so I would only need one tap or spigot.

In doing so, this also allowed both rain barrels to balance more evenly as they filled with rain water. It’s also important to point out that the larger the connection between the outlets the quicker they will balance. If you want you can also take this one step further.

The size of the connection between the outlets can be subtracted from the size of the connection at the top of the rain barrels used to connect them. Therefore making the size of this connection smaller.

And if you’d like to take this one step further again there is no reason why you could not do away with connection at the top altogether and just make the connection at the bottom, between the outlets, the same size as the inlet and just let the water balance from one outlet to the other. There are several choices, it just depends on your preference.

Another important consideration with placing your outlet on the bottom is that your rain barrel will have to be raised off the ground, at the very least, high enough so that the spigot can be accessed. I made a timber stand to support my rain barrels and went to great lengths so it would be strong enough to support the weight.

If you do decide to raise your rain barrel off the ground make sure you support it sufficiently. Water is heavy, and 1 litre will weigh 1 kg. Therefore 200 litres weighs 200 kg.

I made my rain barrels high enough to fit a watering can below the spigot so if you are considering doing this you may be able to find a watering can that is lower and wider compared to tall and narrow. That way you won’t have to raise your rain barrels quite as high.

Adding a Water Level Indicator

When you make your own rain barrel you may wish to add a water level indicator. The one I use is extremely easy to make and is the same as the two I use on my larger rainwater tanks. All you need is to add a T-piece to your outlet and then securely attach some clear plastic hose that extends above the height of the inlet. This then displays the water level inside your rain barrel.

Some important points to consider are, you need the top end of the clear plastic hose above the highest level the water can get to inside the rain barrel, which in most cases will be the inlet. If the water overflows the clear plastic hose it does have the potential to syphon all the water out of your rain barrel.

Also make sure the connection between the T-piece and the clear plastic hose is secure so it doesn’t leak or fail. If you want to make it even more secure you can also add a tap between the T-piece and the outlet so the water level indicator can be isolated when not required.

Once you’ve got your general design settled upon, you then need to consider what you are going to use as parts. I purchased two old plastic drums fairly cheaply and then sourced the other parts from the hardware store.

If you do decide to make your own rain barrel, the parts that you use will depend upon what is available at your hardware store. Basically the main parts of the rain barrel (apart from the drum) will be the inlet, the outlet, and the overflow.

Other considerations may include a water level indicator, a stand or support to raise it above ground level and of course a rain barrel diverter to divert the rainwater to the inlet.

I was able to make two rain barrels and mount them on a stand for less money than I could buy just one. The great thing about it for me was I was also able to incorporate a lot of the tips I’ve spoken about above and as a consequence, for me, my rain barrels are better than a lot you see in the store.

I took two old plastic drums, turned them into rain barrels, placed them on a stand that I built and then enclosed them for aesthetics. These two rain barrels now collect and distribute up to 7,500 litres of rainwater per year to my garden. I thought that was just too much rainwater to let go down the drain. And the best part was, it cost me next to nothing to make.

So if you’re a DIY person like me hopefully the information I’ve provided will be enough to get you started in designing your own rain barrel or if you’d prefer to just buy your rain barrel, at least you now know the features your rain barrel needs to have to make it more efficient.

Importance of a Rain Barrel Diverter

Another important part to consider when you make your own rain barrel is the rain barrel diverter. This normally attaches to the downpipe/downspout just above the rain barrel inlet. These come in many shapes and sizes but when it came time for me to decide what type of rain barrel diverter to use, I decided to use one that I had designed myself.

My two rain barrels are part of a larger rainwater collection system that I designed myself to harvest rainwater from the roof of my house. When I designed my system I was able to harvest rainwater from all of my roof area except for the area serviced by a downpipe which was located at the front of my house.

For my way of thinking I didn’t want to have to place a diverter on my downpipe or a rain barrel at the base of it. As a consequence I was able to place my rain barrels some distance from the downpipe they collect rainwater from and as a bonus I was able to contain my diverter so it wasn’t visible on the outside of the downpipe.

So now as somebody walks past that downpipe on the way to my front door they wouldn’t even know I was collecting rainwater from it and the great thing was the parts for the diverter cost me nearly nothing to buy and it was really easy to make.

Recently I’ve written an eBook on how I went about designing my own rainwater collection system that now harvests rainwater from 100% of my roof area. It shows you how to make your own inexpensive diverter that can be easily adapted to not only direct more rainwater to your rainwater tank or rain barrel but also if you prefer, direct rainwater to your garden. It also contains lots more information about how to make your own rain barrel.

Last Updated on October 12, 2023

Related Posts

Best Aeroponic Tower Gardens in Australia

Best Aeroponic Tower Gardens in Australia for 2024

Aeroponics offers space-saving gardening solutions for anybody and everybody. Whether ...

Subpod In-Garden Compost System Review

Subpod In-Garden Compost System Review

Of all the worm farms you can build into your ...

Vegepod Raised Garden Bed Review

Vegepod Raised Garden Bed Review

Gardens are changing. They are becoming mixed spaces, where our ...

Air Stacky Aeroponic Tower Garden, Hands-On Review

Air Stacky Aeroponic Tower Garden, Hands-On Review

Mr Stacky has transformed Australian gardening over the last few ...

About the author 


Since 2007, our team of gardeners and gardening experts have contributed their knowledge to Aussie Green Thumb. We share with you everything you need to get your garden going and maintain it in tip top shape.

Whether your new to gardening or a seasoned gardener, our tips will help you bring your garden to it's full potential. From big backyards and farms to small spaces, balcony gardens and indoor plants. Let us help you grow a better garden!

Leave a Reply

Your email address will not be published. Required fields are marked

{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}

Stay Up To Date With Aussie Gardening Tips

Join our newsletter to receive helpful gardening tips specific to Australian gardens.


  • Seasonal gardening tips
  • Monthly gardening tasks for each Australian climate
  • Native plant of the month
  • A curated selection of helpful gardening articles
  • Exclusive promotions for Australian gardeners

Stay in the loop for valuable insights for a flourishing garden.

We promise to only send you helpful gardening emails and nothing more.