• September 08, 2022 5 min read

    Can I Water Plants With Softened Water?

    water plants with softened water

    Softened water can do a world of good in a home. From reducing the amount of soap needed to wash clothes and dishes, to extending the life of a water heater, and saving on energy bills. But is treated water bad for plants? You're here because you're worried about your gorgeous garden and plants. Here are some questions you might be thinking :

    • Will softened water kill grass?
    • Will water softener salt kill weeds?
    • Can water softener salt kill tree roots?
    • Does softened water hurt outdoor plants?
    • Will water softener discharge kill grass?


    Softened water is water that has been treated, normally with sodium or potassium, to help remove minerals from hard water. Most water softeners utilize an “ion exchange” process where calcium and magnesium (minerals that make water hard) are exchanged for either sodium or potassium chloride in order to soften the water.

    The amount of sodium or salt in your household water (after processing through a water softener system) can vary depending on the hardness of your water, but it certainly isn’t “salt water”. In fact, on average, those that own a water softener get less than three percent of their daily sodium intake from drinking softened water.

    If your plants get plenty of rainwater, then occasional soft water won’t hurt. But watering plants exclusively with soft water isn’t recommended.  Most of the time it is not a good idea to water your garden with softened water. The reason for this is that softened water typically has a high amount of sodium, which is attained from salt. Most plants cannot tolerate high amounts of salt. The sodium in softened water actually interferes with the water balance in the plants and can kill plants by “fooling” them into thinking they have taken up more water than they have. Softened water can be bad when used over the long-term, your plants won’t be getting the amount of water they require and eventually, they will die from dehydration.

    Your soil is also at risk when using softened water as the amount of salt will build up over time and gradually cause degradation in the soil quality.

    As well as this, the excess salt will also create a hostile planting environment for future plants since the soil will prevent regular water absorption.

    Is it ok to water houseplants with softened water?

    water house plants with soft water

    If you do have a water softener installed for your household, don’t worry; there are ways to avoid this and still give your garden the nourishment it needs: here are a few solutions:

    • Collect and water your plants with rainwater. You can collect rainwater in a barrel or even a plastic garbage can at the bottom of a downspout. Collecting rainwater not only conserves water, but rainwater is usually quite clean. And FYI, rainwater is considered “naturally soft water” because it does not contain a significant amount dissolved minerals.
    • Some plants cannot tolerate chlorinated tap water. If your water seems to have a high level of chlorine (you’ll know by the strong chlorine taste or odor), let the water sit in your watering can for a few days to dechlorinate.
    • Use bottled water to water houseplants–but this can be rather expensive and detrimental to their environment
    • Use potassium chloride instead of regular salt (sodium chloride) pellets in your softener’s brine tank. Potassium is a plant nutrient and is fine for plants and soils.
    • Use water from a reverse osmosis tap to water your houseplants. If you have an RO filter in place, this can be a great water source for everyone in your home. (Pets and plants included!) If you have both a water softener and an RO system, the powerful RO filters will remove sodium in your drinking water, too. A reverse osmosis filter greatly reduces contaminants. And it’s a very popular choice for gardeners with plant diversity. The biggest benefit is creating clean, consistent water. So you can easily control the nutrients and fertilizers you add. Gardeners with bacteria, iron, and chlorine problems will appreciate the benefits of reverse osmosis water. It’s like having rain water from your faucet! Plus, the pH of RO water can be easily changed. So plants with specific acid or alkaline requirements will benefit from the versatility of reverse osmosis.


    For outdoor watering, most water softeners have a bypass valve that allows you to temporarily bypass the softener to access untreated water for your plants. If you link this bypass valve up to an outside tap or another outlet, you can simply water your garden with a hose or fill up a watering can from this source and bypass the softening treatment. Refer to your softener’s owner’s manual or contact a water treatment specialist in your area to learn more.

    How do you treat softened water for plants?

    treat dry soil

    You can try mixing your softened water with collected rainwater or distilled water. This dilutes the effects of the salt in your softened water and makes it less harmful to your plants. But be aware that the salt in softened water will still build up in the soil. It will be very important that you regularly test the soil for salt levels.

    If you have soil that has been watered too much with softened water, you will need to work to correct the salt levels in the soil. If your plants are showing signs of dehydration as a result of the excess sodium, you can simply stop using softened water to water them and begin using regular water, or even better, rainwater! Doing this will allow your plants to start absorbing the correct amount of water they need. There’s also a good chance that your soil will have encountered some damage if you’ve been watering with softened water for too long. The build up in salt leaves you with a soil imbalance that needs to be corrected.

    However it may take time, so be prepared to wait a little while for plant recuperation.

    There are no chemical ways to reduce the amount of salt in your soil, but you can do this manually by frequently watering the affected soil. This is called leaching. Leaching will draw the salt out of the soil and will either push it deeper in the soil or will wash it away. While leaching will help to draw the salt out of the affected soil, it will also draw out nutrients and minerals that plants need to grow. This means that you need to make sure to add these nutrients and minerals back into the soil.

    Just be patient and give your garden time to adapt to the new water quality whilst it rids itself of the effects of the softened water. Over time your garden, soil and plants will return to their previous state of health – just be sure to keep a close eye on everything and monitor soil levels until everything is back to normal.

    Remember, if you have the option of watering your garden with a natural source such as rainwater, do so as the benefits are considerable when compared to regular tap water!


    Mainly, look to your plants for clues. While calcium and magnesium (found in hard water) can be helpful plant nutrients, too much of a good thing isn’t so good. Some plants don’t do well when watered with “hard water”. On the other hand, some plants have a difficult time with softened water. So pay attention to your water quality and look to your plants for clues.