Can You Water Houseplants With Softened Water?

Many households have a water softening system to eliminate the harsh amount of minerals in their water. These systems are designed to make water safer to drink, flow through your home plumbing, and for activities such as showering and laundry. But it’s it safe to use on houseplants? 

Watering houseplants with softened water can harm or kill your plants. In order to remove the mineral hardness of hard water, the softening process uses salt or chemicals. The excess salt and chemicals can have a toxic effect, causing dehydration or the death of your plants. 

This article will explain softened water, how it affects houseplants, what to do when salt builds up in your soil, and how to water your houseplants safely.

The Purpose of Softened Water

Water softening is breaking down and removing the mineral concentration of hard water and making it healthier to consume and use in residential, commercial, and industrial buildings. 

When it rains, water soaks the earth’s surface and flows through the soil, limestone deposits, and rock layers, ending up in a pocket of accumulated groundwater. Groundwater is water trapped between rock layers beneath the earth’s surface. The usual method to access this water body is boring or drilling to create a well to tap into that water supply for residence or other purposes.

While the water flows through the soil, limestone deposits, and rocks, the water picks up minerals such as calcium, magnesium, and iron. The mineral concentration levels depend on the materials of the soil it flows through and how far the water has traveled through the earth’s crust to reach an underground water reservoir. 

The Effects of Hard Water and Why It’s Softened

Hard water can wreak havoc on plumbing systems in homes and buildings for industrial or commercial purposes. The excessive amount of minerals in hard water attaches to the sides of drains and in filter screens, building up over time. As the minerals build up, it causes issues such as clogs and corrosion to plumbing systems. 

This can be a major repair bill, so water softening was implemented to prevent your pipe system and your wallet from suffering.

Aside from the effects hard water has on your home, it’s also affecting everything that uses the water, including yourself. It can damage water appliances, such as your refrigerator and washing machine. And it also affects your skin and hair when you take a bath or shower, leaving your skin dry and your hair brittle.

The Effects of Hard Water on Houseplants

Watering your houseplants with hard water creates an extremely harsh environment for houseplants. A high concentration of minerals, including salts, hinders the ability of your plants to absorb the essentials to complete photosynthesis successfully. You will even notice build-up occurring because the water will leave behind visible white residue on the top layer of the soil.

Too much mineral concentration causes a similar effect on the root system as it does on your home pipe system. The minerals clog the roots and cannot break down and disburse nutrients and oxygen to the stems and leaves. It will ultimately cause the roots and plants to suffocate, burn up from the inability to cool themselves, and they’ll die. 

At this point, you may think softened water is the better option for your houseplants and yourself. 

Well, you may want to rethink that after learning the process of softening water.

The Process of Softening Hard Water

The most effective way to battle hard water is by undergoing a method to ‘soften’ the water to rid the excessive amount of hard minerals in the water. Water softening is accomplished by adding chemicals forming insoluble precipitates or by ion exchange to soften the mineral concentration levels of hard water. Softening water will also include adding a salt-water solution to flush and remove the minerals the system has collected. 

Using these methods has been deemed safe for humans to consume but sometimes makes the water taste terrible. 

Using Chemicals

Chemically treating hard water typically entails using chemicals including, but not limited to, chlorine, ammonia, and lime. A combination of lime and soda ash (sodium carbonate), called lime-soda, is also used. Lime softening (lime-soda treatment) is adding limewater to remove calcium and magnesium salts by precipitation

In municipal water, chlorine and chloramine (chlorine and ammonia) are typically used to treat and soften the water. These chemicals are used in two methods, chlorination and chloramination. The CDC states chlorine levels of up to 4 milligrams per liter are safe for drinking.

During this process, microorganisms and dissolved organic matter are also removed from the treatment.

Ion Exchange

In the process of softening water with ion exchange, the harder minerals such as calcium and magnesium are filtered through resin beads charged with sodium or potassium ions. While water passes through the resin beads, calcium and magnesium are extracted and replaced with sodium or potassium. When the beads max out and no longer absorb the hard minerals, it needs to be recharged. 

To recharge the beads, they are cleansed with a highly concentrated salt-water solution from salt added to the tank. This process removes the hard minerals from the beads, replacing them with sodium or potassium. Once the cleansing process is complete, the salt water solution is flushed with fresh water.

And the process starts all over again.

Ion exchange is the most commonly used method in households. 

How Softened Water Affects Houseplants

Salt is an essential component of removing the minerals causing hardness in the water, so soft water typically contains a higher level of salt that can be detrimental to the health of your plants. 

In addition to using the salt solution, the filtration process eliminates microorganisms and other beneficial components that aid plant health. 

The Effects of Salt on Plants

As discussed in my other article about watering houseplants with bottled water, salt will significantly impact the health of your houseplants. 

Natural salts occur in soil but usually in small amounts safe for plants. 

When added to the soil, salt throws off the natural balance and stresses your plant. Salt causes root dehydration, and while the plant sends water from the leaves to refresh the roots, it, in turn, causes the leaves to overheat and burn. Plants need water circulation and storage to keep cool. 

It also interferes with nitrogen uptake, which reduces growth and hinders reproduction. 

Signs of Salt Build-up

The signs of salt building up in your potting soil is similar to over-fertilizing your plants.

These are the signs of a salt build-up in your potting soil. 

  • Chalky substance on the top of the soil
  • Yellow and wilting leaves
  • Brown leaf tips
  • Dark brown or rotting roots system
  • Droopy plant
  • Growth stunt

If this happens, you’ll need to leach the soil and help your plant heal from the shock.

Treating Salt Contaminated Soil

If you can catch it in time, you can treat your potted plants with a good soil flush, called leaching the soil.

First, remove the chalky residue by removing the soil surface but no more than ¼ inch (0.64 cm) of the top layer.

Pick off all the yellowed and dying leaves and give the soil a long watering to rinse out as much of the salt as you possibly can. To ensure your plant isn’t sitting in soggy water, place your plant on a rag after the excess water stops draining from the pot. The rag will soak up more water drenching the soil to prevent root rot.

When you leach the soil, you’re flushing out the good with the bad, so adding diluted fertilizer, like diluted aquarium water, will help replenish the nutrients needed for your plant to heal.

If you usually bottom feed your plants, switch to top watering to force any leftover salts to drain out of the bottom. 

You can read my other article on how to effectively soil drench your potted plants here: How to Effectively Soil Drench Your Potted Plants

How To Safely Water Your Houseplants

A separate spigot outside that taps into your water may be a good idea before it reaches the softening system. This way, you can use your unaltered hard water by making it safe in a more organic way. There are a few ways to naturally soften water to make it safe for houseplants and your outdoor garden.

  • Sterilizing your softened or hard water by boiling it for at least one minute will sanitize the water, removing everything good and bad for your plants. If you choose this method, you’ll need to add nutrients to the water with fertilizer. Ensure the boiled water has cooled down to room temperature before using.

Do not boil water treated with chemicals such as chlorine and chloramine. The chemicals will not dissipate during the boiling process. If you can smell or taste chlorine in the water, the concentration level is too high to use on plants. 

  • Volcanic rock is a natural material you can use to filter water and is widely used to help with drainage for potted plants. As the water flows through the rocks, minerals are absorbed, learning the concentration. The rocks will not only filter the water but add nutrients and silica during the process. 

Perlite is a melted form of volcanic glass. When mixed into the soil, it aerates, helps with drainage, and filters as you water your plants. It also releases beneficial nutrients for your houseplants to absorb. 

  • Adding peat moss to your soil will also act as a filter, absorbing minerals as the water flows through it. 

Of course, rainwater is naturally soft and can be collected to use for your outdoor gardening and houseplants. That will be an easy and recommended solution if you have a way to collect rainwater. Rainwater is nitrogen-rich and contains minerals essential for plant health and development. 


Watering your houseplants with water containing salt and chemicals from the softening process will negatively affect the health and development of your plants. If you don’t catch it in time, your houseplants may meet their demise. Treat it immediately when you notice a salt build-up in the soil by leaching your plant.

Use healthier water for your plants instead water containing salt or chemicals. If possible, collect rainwater for optimal results and balanced plant nutrition. Otherwise, try natural ways to soften your hard water without including harsh additives.

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

Recent Posts