Good idea!

For sure! You could probably do it with old 10 gallon buckets as long as they stack. Same principle. Then all you need is a bit of waterproof sealant and a spigot.

Its for watering my garden. I water primarily with rainwater. Otherwise I have to lug my watercan to the spigot on the otherside of the house. For me, rainbarrels are a godsend. I have two 55 gallon ones in conjuction with this one.

As for effort, this took me 20 minutes to assemble. Not hard or time consuming.

For me its not about money, its about increasing my rainwater storage using what I had lying around.

We usually get hot dry summers and I have a well. Any water saved from the ground is important.

Not the OP so can't say why they're doing it, but in the UK at least it's really common practice for people who grow gardens because we'll frequently have "hosepipe bans" which means we can't hook our hoses up to the mains to water our gardens. So, you either have stored rainwater (like OP is doing) or... a very dry crispy garden.

I don't know how much it saves money wise, but ecologically using water from rain instead of the mains offsets the amount of water that needs to come out of treatment plants. After all, plants don't care about water treatment really. So they don't need the fancy drinkable tap water. They can have rainwater and that means more for the humans.

Not Op, but another reason why some people might collect rainwater is that the tap water where they live is way to hard. The mineral content is very high and for example most houseplants cannot survive on it on the long-term. My dad also used rainwater for his aquarium fish.

Yes, there are ways to filter it and make it softer, but it's just way easier to just collect and store some rainwater.

So my rainbarrels are daisy-chained. My primary rainbarrel (storebought) is fed directly through a little port attached to the downspout on my garage. The overflow is attached via a tube that feeds my secondary rain barrel (homemade from a plastic 55 gallon drum). What I did here is take another plastic tube from my secondary rainbarrel's overflow and fed it through a hole on the lid of the top ice cream tub in this setup.

So for me, its an overflow barrel for my overflow barrel. Each barrel has to be slightly lower than the last so gravity can feed it from one to the other, hence why I could only stack three ice cream tubs for my setup.

If you were to make this yourself, you would want to cut a hole in the top lid large enough to feed your downspout into. Then you could add as many tubs as you wanted to get the capacity you want.

So this is 3 of these stacked up together. Each is 11.4 liters. All that equates to about 9 gallons. Thats enough to water my gardens probably 1.5 times. I have a lot of garden beds though. If you just had a small one you could do more.

My total setup is 116 gallons (but thats with two large rainbarrels too) which lasts me a long time.

A good rainstorm would fill this setup very quickly.

This setup is but its only three high. As you add more you would have to play it by ear.

There is no maximum here. I think thats a US thing.

what is this limit you are talking of?