Because they’re SPECIAL! Water Sources for Carnivorous Plants

All plants need water, but carnivorous plants are a little high maintenance when it comes to theirs!

Pure water is essential to growing healthy carnivorous plants. In most places, drinking water has too many total dissolved solids (TDS). These are minerals, usually salts, in the water that will burn the sensitive roots of carnivorous plants if used repeatedly. Remember, these plants evolved to receive nutrients from food, not from their roots.

TDS is measured in parts per million (ppm). This measurement can be taken with a handy tool called a TDS meter. I highly recommend EVERY carnivorous plant grower get one of these! Not only can you test to see if certain water sources are safe, it’s a good idea to test your plants’ water trays to see if any minerals build up in the soil over time.

50 ppm is considered the safe upper limit for most carnivorous plants. Ideally, we want 0 ppm, but anywhere up to 50 is okay.

Since tap water isn’t acceptable in most areas, where can we get pure water? Below are several sources from which you can get water for you plants, depending on your personal  budget and needs!

Oooh, fancy stock water image.
Oooh, fancy stock water image.

Distilled water by the gallon. Also called deionized water in the UK. This is the easiest and most cost-effective way to get pure water when you’re just starting out. Distilled water is often under $1 per gallon. If you have just a few plants, 1-3 gallons can last a week. Until a few months ago, this is what I was doing. But soon I was making multiple trips to the store, and using 8-10 gallons a week! I had to move on to a different method at that point.

If no distilled water is available, look for water purified by reverse osmosis (RO), but WITHOUT minerals added for taste. This water will also have very low TDS.

Water refilling stations. Many grocery stores have RO water via their refilling stations. The cost is around 30 cents a gallon, but beware! Not all of them are the same! Buy one gallon first and test it with a TDS meter. I got water from a high-end, boutique grocery store which measured around 200 ppm, pretty similar to my tap water at home. I tested water from a less fancy grocery store, which measured at 10-12 ppm. SOLD!

ZeroWater filtration system. These are an option if you don’t need a lot of water, but still don’t want to purchase it by the gallon. They’re small, easy to store anywhere, and come with a TDS meter! Filters can be expensive to change, but remember you can let your TDS to increase up to 50 ppm, and it will still be safe for your plants. Because I’m paranoid, I probably wouldn’t let it go past 30 ppm but that’s just me!

Consider a ZeroWater system for plants that are sensitive to minerals in your tap water
A ZeroWater system can fit on your countertop or in your fridge!

Home Reverse Osmosis system. This is one of the methods with a higher upfront cost, but will pay for itself quickly if you have a large collection and need lots of water. There are many different RO systems to fit your various needs. Some fit under a kitchen sink and connect to your faucet. Others are portable and can sit on a counter top or connect to a garden hose.

Reverse osmosis home filter system
Example of an under the sink RO filter system

Rain water. Rain is some of the purest water there is, so use it when you can! It can be as simple as leaving containers out when it rains, or you can invest in a rain barrel. Rain barrels can be fancy and decorative like this or super basic and portable like this. (Note: rain barrels are currently illegal in Colorado. I’m not encouraging any illegal activities, just use your best judgement!)

Make your rain barrel a decoration in your garden!
Example of a fancy rain barrel with a planter on top!

If it snows in your region, you can also collect and melt snow for your plants!

Other possible water sources include:

  • distilling your own water at home. If this is what you want to do, godspeed! I envy your patience and resourcefulness, though not your energy bill.
  • catching water from an air conditioning unit. I’ve read mixed results from this method, so I recommend testing with the trusty ol’ TDS meter before using this water on your plants.
  • Water stores. You can buy water in bulk from specialized water stores (as well as RO units and such), but these stores aren’t available in all areas.

Was this post helpful to you? If so, let me know in a comment below! And share this post via the buttons to your left if you think other people can benefit from this post!


  1. Rich says:

    Very informative article on water sources! I myself have run into this problem. What started as 3 carnivorous plants quickly turned into a basement grow rack and 5 standard nursery trays filled with plants. I found myself buying water by the individual gallon. Next I was filtering my own using a product called ZEROwater. I must say – it worked extremely well. It brought my tap water from 300 ppm to 0 ppm as advertised. Depending on your water quality prior to filtration, the filter’s efficiency will decline and you’ll notice your ppm’s begin to climb. The filters are quite pricey – but the company offers incentives on sending in your old filter…All-in-all it was just too much work for me. The unit did not filter the water quickly enough to address the volume I was using. I’m currently purchasing 5 to 10-gallons of water at a time at a local grocery store from one of the machines you mentioned. I get it for $0.45 per gallon and it nearly always has a TDS reading of 0 ppm. My next step is likely going to be installing a reverse osmosis unit onto the sink in my basement as my collection grows.

    • Maria says:

      Thanks for the comment, Rich! Yes, I’ve read about Zerowater and decided not to include it in the article based on exactly what you said. All I’ve read from other users is that it doesn’t last long enough and doesn’t produce enough pure water to justify the price of the filters.

  2. katyadog1 says:

    Very nice article! I’m surprised to hear rain barrels are illegal in CO– seems strange to me.

    I have a 65 gallon decorative rain barrel. Definitely one of my best investments.

    • Maria says:

      Thanks, katya! Yeah, it’s pretty weird legislation being debated on right in Colorado right now. Case studies have shown that saving rain water is beneficial to communities in a drought.

  3. Rob says:

    Hi Maria,

    Thank you so much for sharing this. This is brilliant! I remember when I was buying distilled and when it was manageable. Good times! I also wanted to mention that I use the ZeroWater filter ( for my home and office carnivores – it will bring TDS down to zero and it actually lasts me quite a while. (Life of filter will depend on TDS out of tap, of course.) My filter has been going strong for about 6 months and my ppm is like… 2 right now. It comes with a TDS meter too! It’s great for smaller manageable collections. 🙂

    • Maria says:

      Hey Rob! Thanks for the comment and feedback! After reading yours and Rich’s comments, I decided to add Zerowater into the post as another option! Like anything, what works for one person may not work as well for another. Always good to have options!

  4. Brandon says:

    Very interesting; I had only ever considered catching rain water, which is a bit out of the norm since I live in the desert, but it’s been a duper wet year for us and I usually just put my plants out in the rain to catch what they will. I wasnt aware that you could buy reverse osmosis systems for your home… I’ll definitely have to look into getting one of those meters, though, especially if I can find a water source that can help yhe trips to Walgreens xD

  5. Marcy says:

    Thanks for the info. I happen to live in Colorado. Is it the only state that has that law? I collect rain water from the down spouts but we havent had much rain this year so I am forced to buy by the gallon.

    • Maria says:

      Thanks for commenting, Marcy! I believe CO is the only current state with that law, but I’m not 100%. It looks like there is legislation moving to lift the restrictions on water harvesting, so that’s some good news!

  6. Shannon says:

    With this current heat wave we are having, I pulled out my zero water filter because I ran out of distilled water jugs before payday. My mom got it for me years ago but it made my water taste fishy after so many filters. My old filter is giving me 9ppm right now and I have a new filter ready when it gets higher. I was going to try to sell it but not now.

  7. Douglas says:

    Good information, I would not have know that the minerals would be detrimental to the plants.
    I use RO/DI water filters for my Saltwater fish tank so I’m ready to go.

  8. Meredith McSwain says:

    I was curious about the reason for the Colorado law so I looked into it and I just wanted to let you know it looks like that law has been overturned as of May 2016.

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