Can I Water Plants, Lawns, and Gardens with Softened Water?

Is Softened Water OK for Plants, Lawns, & Gardens? blog header

Softened water brings several benefits to a household. It minimizes soap usage when washing clothes and dishes, extends your water heater’s lifespan, and optimizes energy bills. But is it okay to use softened water for plants, lawns, and gardens?

The Scoop on Salt

The majority of water softeners employ an “ion exchange” mechanism, where the water-hardening minerals, calcium and magnesium, are replaced with sodium or potassium chloride to soften the water.

The sodium or salt concentration in your household water, post-softening, may differ based on the original hardness of your water, but it’s far from being “salt water”. In fact, homeowners with a water softening system get less than three percent of their daily sodium from drinking softened water.

Ensuring the Happiness of Indoor Plants

If you’re apprehensive about the additional sodium from softened water affecting your plants, consider these alternatives:

  • Use rainwater for watering your plants. Rainwater, which you can collect in a rain barrel or a plastic bin at a downspout’s bottom, is a great option. Not only does this practice conserve water, but rainwater is also quite clean. Plus, rainwater is “naturally soft water” as it doesn’t contain a significant amount of dissolved minerals.
  • Some plant species can’t handle chlorinated tap water. If your tap water smells or tastes strongly of chlorine, let it stand in your watering can for a few days to allow the chlorine to evaporate.
  • Watering houseplants with bottled water is an alternative, but it can get costly.
  • Using water from a reverse osmosis tap for your houseplants can be a wise move. Despite the initial cost of the RO unit, reverse osmosis water is typically inexpensive—just pennies per gallon.
  • Try using potassium chloride instead of common salt (sodium chloride) pellets in your softener’s brine tank. Potassium is a plant nutrient and is harmless for plants and soils. 

How to Keep Your Lawn and Garden Healthy

For outdoor watering, many water softeners have a bypass valve that provides temporary access to untreated water for your greenery. You can find more information in your softener’s manual or consult a local water treatment specialist to learn more.

You might also want to get a separate line installed for the outdoor tap by a professional plumber. This will let you water your plants with untreated water, while still benefiting from softened water indoors. 

Mainly, pay attention to your plants. While calcium and magnesium (found in hard water) can be beneficial, an excess isn’t always better. Some plants might not thrive with “hard water”. Conversely, some plants might struggle with softened water. Hence, it’s essential to monitor your water quality and interpret your plants’ responses. 

Is Chlorinated Water Bad For Your Lawn?

Chlorinated water can also impact your lawn, but typically, grass and many outdoor plants are quite resilient and can tolerate a certain amount of chlorine.

Most municipal water contains a small amount of chlorine, which is used to kill harmful bacteria. While high levels of chlorine can damage plants by causing leaf burn or impacting soil health, the level of chlorine in most municipal water supplies is generally low enough that it doesn’t pose a significant risk to lawns or outdoor plants.

However, if your water is heavily chlorinated, it might cause some harm over time. Just like with houseplants, if you notice signs of distress such as yellowing or browning grass, it might be due to excessive chlorine.

If you are concerned about the chlorine levels in your water, for a large lawn, you should consider installing a filtration system to dechlorinate the water.

Growing Your Garden Right

Gardening can be an enjoyable pastime, but plants can be temperamental. Aside from water quality, here are four suggestions to ensure your plants’ happiness:

  • Ideally, water your plants in the morning. This gives the moistened soil time to dry out during the day. Plants that remain wet during the cooler night hours might suffer from fungal or bacterial diseases. 
  • Use lukewarm water. After each watering session, refill your watering can and let the water stand. This ensures the water is at a comfortable temperature when you water next. 
  • Avoid overwatering. Check the soil’s dampness before watering. Overwatered plants appear limp, their leaves start to yellow and drop. Similarly, under-watered plants look wilted, but their leaves turn dry and brittle before they fall.
  • Understand your plants needs.  Each species has a unique growth pattern. Some are active during fall and winter but slow during summer, while others grow rapidly in spring and summer but go dormant in fall and winter.

Uncertain about your water type? Discover whether your household’s water is hard, soft, or somewhere in between. Visit WaterTech’s Hard Water resource to learn the tall-tale signs of hard water and what can be done about it. Also, a great way is to contact a local water treatment professional and request a FREE WATER TEST.

Hard Water in your home?


13 Responses

  1. I have a beautiful lawn that I am wanting to maintain well for the Summer. I have been looking for information to see if a water softener will affect my lawn, and it looks like it won’t, but I still have to keep an eye out. One thing that I was told was to water at night, but now I’m seeing to water in the morning, so I will have to test it out.

    1. Don’t do it, it will kill your plants. In learning the hard way. I just got one and my poor lemon tree has yellow spots. Look for yellow spots in the tips of all plants.

    1. Haven’t found any definitive studies about the affects of potassium chloride on plants, but many gardeners feel seem to feel that using water softened with potassium pellets (to water plants) is a better alternative.

  2. Your lawn guy is half right…except that night watering can lead to fungal diseases in lawns. Best time to water is early morning.

    1. Agreed. I’d rather have my plants burned by the sun a little bit then have them taken over by fungal diseases. I water early morning before the sun is at it’s high point to avoid both issues.

  3. I can’t find anyone answering whether the the softener “exchanged” exhaust water is Ok for plants. In theory it should actually be good, filled with carbonates and magnesium, i.e. very “hard” water. But I want to make sure.
    I’ve set up the softener to only work on the hot water in the house, which, I think, strikes a good balance between the appliances typically using hot water and humans (and plants) usually using cold or mixed water for consumption.

    1. Watering with the exchanged water isn’t good because of the small amount of sodium that’s in the water.

      1. Isaac, do you mean it is too small or do you mean the remaining amount is still a problem? I’ve measured the hardness of water, and it is very hard. I don’t have any means at hand to measure the sodium or chlorine content there. From the scarce info I could find, the backwash water may contain significant amounts of sodium and chlorine. Chlorine, however, should vent out, if I leave water stand for several days, right?

  4. A new flower bed I built failed to thrive several plants died, I moved 2 to new location, made no difference.
    By passed the new water softener. Everything recovered.
    Moral of the story, don’t put salt on the potatoes til they are cooked.