Does Rain Barrel Water Go Bad?

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If you’re considering getting a rain barrel for your backyard, you’ve probably come across claims that rainwater goes bad in the barrel. This can be concerning if you’re a busy person, and, let’s be honest, who isn’t these days? Maybe you have to leave rainwater in a barrel for a while before you can use it to water your plants or lawn. But the internet is full of conflicting information about this. So, let’s answer this right now. Does rain barrel water go bad?

Because water itself doesn’t expire, rain barrel water doesn’t technically go bad. However, that doesn’t mean its safe for drinking as stagnant water is a breeding ground for algae, mold, and insects. For this reason rain barrel water should only be used for lawns and gardens.

Safety Note: No matter what rain barrel water looks or smells like, it should never be consumed by humans or pets. You should never use collected rainwater directly on vegetables that you plan to eat. Instead, you should apply the water around the base of these plants.

Common Rain Barrel Problems

Rainwater hits your roof first, then travels down off your roof and through your gutters to finally end up in the rain barrel. That journey allows it plenty of time to pick up some bacteria and plant particles. This isn’t usually a problem when the water is used within a few weeks, but when it’s allowed to sit for a month or more, the water can start to have some issues. 

The most common include a foul, rotten egg smell, algae growth, and a mosquito infestation. While all these are not pleasant to deal with, they don’t make the water “go bad.” In fact, the water is still usable for plants, ornamental gardens, lawns, and even veggies when poured at the roots. 

Still, no one likes a stinky or mosquito-infested rain barrel, so we’ve got you covered below. 

Why Does My Rain Barrel Stink?

Chances are, at some time or another, you’ll experience a potent, sulfur smell from the rain barrel. This is due to bacteria gathering in the barrel. While unpleasant, the water is still perfectly safe to use on plants as advised above. If you don’t like the smell, there are a few things you can do to prevent this from happening. We’ll cover that, and how to keep bugs out of your rain barrel, below. 

How to Prevent Rain Barrel Problems

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Most people would probably prefer their rain barrel water not to be smelly or discolored. There’s something nice about pouring nice, clear water on your flowers or around your veggies. If you’re one of those people, we’ve included some rain barrel hacks to do at home. 

Avoid Clear or Light-Colored Barrels

The color of your rain barrel can have an effect on the growth of bacteria and algae inside. Clear or light-colored barrels that allow sunlight to reach the water are more likely to have issues with unpleasant smells and strange slimes growing inside. Dark or opaque rain barrels are best.


You can also place your rain barrel in a shady area to reduce the likelihood of bacteria and algae growing inside. Once again, this comes down to limiting the sunshine that touches the barrel. You can pick a side of your house that gets very little sunshine and install the rain barrel there.    

Screen Size

One of the easiest ways to keep your rain barrel nice and clean is to buy a mesh screen. Some rain barrels come with no screen or a large screen, letting debris flow through the holes easily. The more debris ends up in your barrel, the more likely you’ll have an issue down the line. There are plenty of screen options out there, and they don’t have to be made specifically for rain barrels. 

Just be aware that there’s a happy medium. A very fine mesh screen is likely to need cleaning often, as plant debris will build on it and eventually cause a clog. A screen with medium-sized holes is best for rain barrels. 

Gap Between Downspout and Rain Barrel

Another effective rain barrel hack is as simple as connecting the downspout directly to the rain barrel. Having a gap between the two simply allows for more debris or insects to find their way into the barrel. You can use one of these to close the gap and keep your rainwater clean. 

Clean Gutters

A great way to keep your rain barrel clean and fresh is to go to the source: the gutters. Clean gutters help to keep the rain flowing through them clean, as well. But when there are branches, pinecones, dead leaves, and other organic matter in them, they’re likely to attract bugs and bacteria. Then, when it rains, it all gets washed down into your rain barrel. 

Gutter Hacks

If cleaning your gutters every month or two doesn’t sound fun, here are a couple of gutter hacks to help you keep clean and clear rainwater in your barrel. The first is to install a gutter guard, like this one. It will allow water to flow down. The smallest bits of plant matter can get through, but not enough to be concerned over. 

The second, less involved solution is to install a screen over the downspout entrance. You’ll still have to clean your gutters out once in a while, but the screen provides an extra layer of protection against unwanted debris in your rain barrel. You can get a 4-pack of screens here

How to Keep Bugs Out of Your Rain Barrel

Let’s talk about bugs. Mosquitoes in your rain barrel may not mean anything in terms of plant watering. But it will definitely mean something to you and your family. You can use these anti-mosquito larvae tablets if you notice a mosquito problem.

Even with the best of preparations, mosquito eggs can get washed into your rain barrel. So use these tablets to get rid of them and prevent further breeding. 

How Often to Empty Rain Barrels

Now that we’ve covered all the tactics you can use for installing and optimizing your rain barrel, let’s take a look at how often to empty the water. The fact is that regularly using the water in your rain barrel is the best way to keep it free from algae, bacteria, and mosquitoes. 

Ideally, water shouldn’t sit inside the barrel for more than 2 weeks at a time. After two weeks, the water begins to grow stagnant, which is when things start to go wrong. However, there is no hard and fast rule for the maximum amount of time you can leave water untouched in a barrel. It depends on many factors like humidity, heat, sunshine, and any sort of existing bacteria in the barrel. Many people find that they can leave water in a rain barrel for months at a time with no issues. 

Remember, the water doesn’t go bad. Unless something is drastically wrong (like a dead animal in the barrel) then you can use the water for typical rain barrel purposes. 

How Often to Clean Rain Barrels

Generally, rain barrels only need to be cleaned once or twice a year. However, some homeowners prefer to clean a barrel as soon as it starts to stink or develops any algae growth. 

To clean a rain barrel:

  • Empty the water
  • Use white vinegar or baking soda for a natural cleaning solution or bleach for deeper cleaning. 
  • Scrub down the sides if possible. If not, swish around the cleaning solution and spray out with a hose. 
  • Inspect the spigot and clean if need be. 

What to Add to Rain Barrel Water to Keep it From Smelling

According to some studies, a cap of chlorine bleach can help keep a rain barrel from smelling. This amount is thought to be safe but many homeowners are hesitant to put bleach in the water they use on their edible veggies. It really comes down to personal preference. If you do add chlorine, wait 24 hours before using the water. 

In Conclusion

Rain barrel water doesn’t go bad. The biggest reason for this is that rain barrel water isn’t meant for drinking or bathing. It should only be used to water plants. Vegetable plants should be watered around the base and not on the plant itself. The roots of plants are extremely effective at taking what they need and letting the rest go. 

Algae and a pungent smell don’t mean the water is bad, although some people would rather have clear water that doesn’t smell. It’s a matter of preference and should be treated as such. But for best results, use the water from the rain barrel within 2 weeks, and clean it out once or twice a year.

Justin Childress

Justin Childress is the creator of He is also a devoted husband and father of his 1-year-old son Gabriel. Justin enjoys spending time with family, reading, and, of course, contributing to Read more about me or follow me on Pinterest to stay connected.

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