How to Dechlorinate Water For Houseplants

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Chlorine isn’t always that big of a deal.

Where I live, the tap water is pretty good. Scottish water is even better. Though I try to use aquarium water for my Calathea, the occasional bit of tap water doesn’t negatively affect them.

If you’re not sure how good your tap water is, you can get it tested. Aquatic or pet shops usually provide this service, but if not, you can test it at home with an, er, home test kit.

Do you need to dechlorinate water for house plants?

As I said, test your tap water. There’s no point worrying about something that may not be an issue.

Tap water can contain up to 4mg of chlorine per litre and be considered perfectly safe for human consumption.

Here in the UK, the chlorine levels in tap water is about 0.5mg per litre. If your tap water is testing at higher levels than 0.5mg per litre, you might consider taking steps to dechlorinate it.


Chlorine isn’t a plant killer. It just might give them brown leaf tips. Don’t let it stress you out.

Is filtered water dechlorinated?

Yeah. Whack your water through your Brita filter if you so desire.

A lot of people like to use filtered water on their house plants because tap water can contain a lot of *stuff* that plants aren’t fond of.

What stuff, you ask? The usual: fluoride, nitrate, fucking ARSENIC.

They don’t PUT arsenic in the water, it’s just there a contaminant. So many people like to filter it out.

As it turns out, chlorine is the least of our worries!

Can you use distilled water rather than dechlorinating tap water?

You can, but distilled water isn’t recommended for use on house plants.

Distilled water is pure h20, and doesn’t contain some of the beneficial contaminants found in tap water (such as copper).

Filtered water still contains minerals dissolved in the water, so it can pass these on to the plants.

Interestingly, if you research this topic, it says that filtering filters out unhealthy minerals, but leaves healthy ones (distilled water doesn’t have anything other than hydrogen and oxygen). If this is true, how does the filter ONLY filter out unhealthy stuff?? How??

Anyway, distilled water is fine occasionally, but don’t use it long-term unless you’re incredibly diligent about fertilising and have the perfect NPK for each plant.

Some plants apparently actively hate distilled water, such as orchids. I have no idea if that’s actually true, or just one of those things that someone once said and we all repeated.

I will use rain, tap and aquarium water only. I’m not buying water AND paying my water bill.

How to dechlorinate tap water:

If, for some reason, you have high levels of chlorine in your water, you can dechlorinate it. Which method you choose depends on how chloriney your water is.

1 – Add dechlorinator

This is my preferred technique because if it can get tap water to fish-safe levels, it will also be plant safe. House plants are hardier than tropical fish. Also, I like that you can measure out the right amount of dechlorinator and be pretty sure that it’ll remove all the nasties that’ll kill your fish plant.

I like Seachem Prime, because it’s the one my boyfriend uses, so I can steal it for free.

To be honest, I rarely add dechlorinator to my tap water – instead, I use water from the aquarium directly (or Dave empties it into a big water drum thing). You absolutely could if your water is crappy though.

Dechlorinator, especially Prime, can seem expensive, but you only need a tiny amount. The only downside is that it smells grim (it doesn’t linger though).

2 – Leave it sat out overnight

This isn’t a particularly good method of removing chlorine – how much it actually works is a contentious issue in the house plant community.

Actually, it does remove chlorine, but not chloramine. It varies depending on your council which your water is treated with – chloramine is more effective at making water safe to drink than chlorine (because it lasts longer and is harder to get rid of) but is also, er, harder to get rid of.

In my opinion, there probably isn’t enough chlorine in the water for it to be dangerous, and if leaving it out overnight gets rid of some…great.

What leaving water out overnight DOES do, is ensure that the water is room temperature, which is best for your plants.

3 – Aerate the water

Adding an air pump to your water and letting it bubble for half an hour is a good way to remove chlorine.

However, it’s more effort than adding dechlorinator. I’d only recommend this if you have an air pump hanging around.

Many avid propagators keep air pumps in their arsenal to save them from having to do water changes every couple of days.

An air pump is definitely a useful thing to have – they can be great for rehabbing plants with root rot for example – but I don’t think it’s worth going to get one just to dechlorinate water.

4 – Boil the water

This is a method that’s PERFECT for some people, but hilariously unrealistic to others. I’d have to boil the kettle dozens of times to get enough water for my plants. Unless you have, say, two plants, it’s really not worth it.

I know I don’t have to say this but cool your water. Let’s not go boiling our plants.

So there we go, four methods to dechlorinate water. Though the valuable information here is that if you can happily drink your tap water, so can your plants.

Caroline Cocker

Caroline is the founder and writer (and plant keeper) of Planet Houseplant

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