Rain barrels are a great water conservation option, but there are a few things you need to know to avoid a mess and get the most out of your storage. We'll share how to make a rain barrel (or get one cheap or decorative), plus installation and maintenance tips for rain water collection.
How to Make a Rain Barrel for Rainwater Collection
There are three key elements in every rain barrel system.
- a way for the water to get in, with a screen to keep debris out
- a spigot to use your collected rainwater
- an overflow, in case your rain barrel gets too full
For a system like ours, you need:
- 55 gallon plastic drum (or food grade barrel from large restaurant)
- brass faucet with fittings
- Fiberglass window screen
- Second ¾ inch faucet or PVC pipe for overflow
- Bulkhead fitting to attach barrels to each (if you have more than one barrel) or to act as the back for the faucet
- Roll of Teflon tape and Caulk or plumbing sealant, to provide a more snug fit
Rain Barrel Stands
We want to get our rain barrels high enough that we can get a bucket under the spigot. This means we need a stand.
Keep in mind that water weighs about eight pounds per gallon, so whatever you use for a rain barrel stand; make sure that it’s sturdy.
A 55 gallon drum full of water will weigh over 450 pounds. Make sure your stand is strong and level – you don’t want those barrels tipping over on someone.
We paired up six concrete deck footings with a small reinforced treated wood deck. You could also use concrete blocks, or a combination of concrete blocks and pavers, as shown in the video below.
We don't recommend downspout filters on the roof. They are hard to clean, and can create ice damns in your gutters and downspouts.
A couple of options for downspout and gutter filters include:
- Gutter cap or Gutter Filter to keep leaves and debris out of the downspouts (requires a ladder to clean them)
- Downspout filters (not roof mounted) (these are within reach for cleaning)
For our rain barrel, we cut around the inside of the cover. Then we inserted a sheet of fiberglass window screen to keep out debris. I’ve also seen small holes cut in the top to fit a skimmer basket covered in fiberglass screen.
You don’t want to have an open top, because this is an invitation to mosquitoes and other bugs.
Make sure your opening is big enough to capture all the rainwater from your downspout. You also want to be able to clean your filter or screen.
Do not skip adding a screen to your rain barrel! I’ve seen guides that don’t use a screen because they route the water directly in through a tight opening. This is a bad idea.
We have a high roof, with no trees around, and yet we still get bits of branches, leaves, tree seeds and other debris in our screen.
I don’t know if the birds drop them or the wind blows them, but there are chunks that would build up in your rain barrel.
You can include a roof washing system that diverts the first round of rain from your roof around your barrels so you store cleaner rainwater, but for garden use it's not critical.
The book “Rainwater Collection for the Mechanically Challenged” has a great tutorial on building your own roof washer, or there are roof washer kits available online.
If you want to collect rainwater for potable use, a roof washer is essential.
If you don’t want to reroute your downspout to the rain barrel, there are downspout diverter kits that insert into the side of a downspout.
Mark a spot at least two inches from the bottom of the water barrel. Why two inches above the bottom, instead of closer?
That spacing will give you room to mount your faucet, plus it’ll help you avoid any sediment that builds up in the bottom of your rain barrel. Even with a screen, some sediment will build up – not a ton, but some.
If you get a good quality brass faucet, you should be able to screw it directly into the wall of your barrel wall once you’ve drilled your hole to match the faucet, as demonstrated in the video below.
If you find that you need a tighter fit, or want to extend the faucet farther out, you can use PVC fittings and Teflon tape.
Rain Barrel Overflow
We have a two barrel system, with the first barrel connected to the second barrel via PVC fittings. The friend who built our rain barrel system fitted the overflow to the top of the second rain barrel because it was quick an easy.
It would work better located on the side, slightly above the PVC connection between the two rain barrels (this is where you use the bulkhead connectors – one per barrel).
Whatever you decide to rig up for an overflow, whether it’s a garden hose or PVC fittings, make sure the water flows away from your building, just as you would a downspout. You may even decide that you’d like to add a rain garden off of the overflow.
Maintaining Your Rain Barrel System
Because we have high winds, we added strapping to hold the barrels down when they're not filled. For winter, we drain the rain barrels and bring them into the greenhouse.
Water expands about 11% when it freezes, so a frozen rain barrel is likely to have damaged fittings.
If you don’t have a spot to move your barrels inside for winter, drain them and cover them so they can’t gather water or snow, and divert your downspout to its normal course.
We add a downspout extension for winter, and take it off again in the spring when the barrels go out.
In spring, before putting the rain barrels back into action, give the barrels a good cleaning. You want to scrub them out at the beginning of the season to make sure you're not starting off with contaminated water.
For cleaning your rain barrels, you’ll need a long handled scrub brush, or you’ll have to crawl in to your barrel. I improvised by duck taping a piece of firewood to a brush with a shorter handle.
Make sure to clean your screens, too, and double check that your faucet and overflow are clear of obstructions.
Algae in Your Rain Barrel
If you use a translucent barrel, you're more likely to algae growth due to sun exposure. Try covering your rain barrels with a tarp, painting your water barrels or using a wooden surround to block the light.
If you're not opposed to goldfish in your rain water, they will eat the algae, as well as mosquito larva. Just make sure that your rain barrels don't run dry, or you'll kill your fish.
Keeping Mosquitoes out of your Rain Barrels
Use a screen to keep mosquitoes from having easy access to your rain barrels.
If you find that they still somehow manage to get in, a couple drops of vegetable oil on the water surface will prevent them from laying eggs. (This will make your rain barrels messier, so you need to clean them more frequently. You’ll also need to add more oil from time to time.)
Another option is to add a couple of goldfish to your rain barrel. They’ll eat the larva and add some fish poop fertilizer to your water. (This is not recommended if you think you may need to drink the water.)
Mosquito dunks are another commonly recommended option, but not my top choice. The active ingredient in mosquito dunks is “Bacillus thuringiensis subspecies israelensis” (Bt), which attacks the larval stage of mosquitoes.
Bt occurs naturally in soil bacteria. Now it's being genetically engineered into corn and other crops, and some insects are becoming resistant. I prefer to stick to simpler control method.
Finding Rain Barrels for Sale, Cheap Rain Barrels or Decorative Rain Barrels
Many home improvement stores now offer plain and decorative rain barrels and rain barrel kits, or they can be purchased through catalogs or online. There are decorative rain barrel options now, such as:
Where space is limited, there are rain barrels that are flat on one side to sit flush against a building.
There are also some local programs that supply rain barrels at reduced cost to encourage rainwater collection.
For free and cheap water barrels, inquire at local food processors. Often they receive ingredients in 55 gallon drums. For instance, we were able to get the barrels we used for our rain collection system for free from a nearby meat shop.
Make sure you use FOOD GRADE BARRELS, not barrels that may have contained toxic substances.
Are you ready for Rain Barrels?
Natural rain water is softer and easier on your garden plants. My grandmother always washed her hair every Saturday night with water from her rain barrel.
If you happen to have a good water filter such as a Berkey, you can use it for drinking water in case of emergencies.
I hope you found this post helpful. Drop a note below if you have any questions or tips to share.
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Originally published in 2011, last updated in 2020.