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Garden sprinkler system watering the plants with the text: Should I filter my garden water?

Should I Filter My Garden Water?

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It’s no secret that watering might be one of the most important things that you do as a gardener. Although watering the garden is not overly complicated, poor watering can result in weak, damaged, and unhealthy plants. Poor watering can look like watering too much or not enough, but it can also be a result of poor-quality garden water.

In many areas, the water supply contains chemicals and heavy metals that can be harmful to plants and beneficial organisms. Luckily, you can use a water filter to remove impurities like lead, asbestos, benzene, and chlorine. Depending on your water source, it may be a good idea to filter your water to ensure a thriving garden.

You might be asking yourself: how do you know if your water is clean and safe? Is a garden water filter necessary? In this article, we’ll answer these questions and provide step-by-step guidelines to improve your water quality. We’ve also included recommendations for choosing the best water filter for your needs.

How does water quality affect plants?

The quality of your garden water can significantly affect the health of your plants. Not only is water a source of hydration for plants, but it’s also a means of nutrition. Water contains minerals and nutrients essential for healthy growing, and it allows plants to uptake nutrients from the soil.

Green watering can pouring water over plants in a garden

Whether you’re growing plants in a greenhouse, hydroponic system, or garden, using high-quality water is a must. Although it’s hard to see or even taste differences between different water sources, it’s important to check for certain qualities.

The most important factors to consider are: pH, alkalinity, dissolved solids, soluble salts, and nutrients.

While high-quality water provides plants with much of what they need, poor-quality water can slow down your plant’s growth, reduce its aesthetic quality, and even lead to the (gradual) death of your plants.

For example, high levels of soluble salts can damage plant roots, resulting in poor nutrient and water uptake. High water alkalinity can adversely affect the soil pH. Chemical or mineral contamination can even become a health hazard.

We don’t want to scare you, but it’s important to recognize that not all water is created equally. So let’s dig in to find out more about water quality and when to use a filter for your garden!

Can I water my plants with tap water?

If you’re like most gardeners, you probably water your plants directly from the tap. Depending on your area, however, tap water may not be adequate for watering your plants. The first thing to check is the source of your tap water. Are you on municipal water, do you draw water from a well, or do you use rainwater?

One common water issue experienced by gardeners using municipal water is hard water. Hard water contains high levels of dissolved minerals such as calcium and magnesium. Dissolved minerals, or soluble salts, are good in small quantities, but watering your plants frequently with hard water can be damaging. Over time, a layer of dry minerals forms on the soil that can actually block water and nutrients from getting in!

Additionally, chlorine is probably the most common chemical present in municipal tap water, due to its ability to sterilize. In high enough quantities, however, chlorine can be toxic to plants. Watering your plants regularly with chlorinated water can weaken them over time as the chlorine builds up in the soil.

Additionally, whenever you water your plants with chlorinated water, it will kill some beneficial bacteria and microorganisms. Fortunately, they reproduce rapidly enough that this is not a huge issue, but we want to keep those little “bugs” alive as much as possible! Adding compost to your garden is a good way to restore microbial life.

Do I need to filter my garden water?

Do you have a water filter under your kitchen sink to filter the tap water before you drink it? A similar system can be put in place to filter water for your garden, removing chemicals, pollutants, and even solid particles.

Filtering your garden water helps you rest assured that your plants are getting the clean water they need to grow beautifully and healthily. Garden water filters will help you protect your plants from toxic chemicals and excess minerals as well as supply essential nutrients.

Still not sure? Keep reading to see if a garden filter is the right move for you!

How to find out if you need a garden water filter

If you are absolutely certain that your water is free of heavy metals, pollutants, chlorine, and more, then maybe you don’t need to install a garden water filter.

But, you can only know the quality of your water through testing. And, unfortunately, studies have shown that municipal water across the U.S. contains alarmingly high amounts of heavy metals including lead and arsenic.

You can find out if your garden water is clean and safe at official testing centers, but this can be expensive. If you live in the U.S., you can check the annual reports in your area through the EPA (Environmental Protection Agency) to get an idea of your local water quality.

For a more accurate representation of your water quality, you can test the water yourself with an at-home kit. Water quality kits test for various kinds of contaminants such as chlorine, lead, or bacteria. You should also check for soluble salts, alkalinity, and pH level. You can find home water test kits online or at most hardware stores.

If any of the results are unfavorable (for example: high levels of chlorine, heavy metals, or alkalinity), you should consider installing a garden water filter.

Do I need to filter rainwater?

Because it falls from the sky, rainwater might seem like the safest option to use when watering your plants. In its pure state (i.e. rain), this is true. Rainwater is naturally soft and doesn’t contain heavy chemicals such as chlorine, fluoride, and soluble salts.

In fact, rainwater is thought to help eliminate excess salt in the soil, a process vital for the health of your plants. However, it’s important to note that there are conditions in which filtering rainwater may be necessary, especially when it’s collected and stored before use.

Most importantly is the question of how you store rainwater. Rainwater that falls on your roof and collects in a rain barrel is likely to pick up dirt, bird droppings, and dust. As it comes into contact with your roof, it might even pick up traces of lead, zinc, and other heavy metals. In this case, filtering is essential.

Rainwater is a natural, eco-friendly watering option. But if you’ll be collecting and storing rainwater, make sure to use a clean container or barrel. Place the barrels properly so you can collect rainwater directly. Ultimately, rainwater can serve as a great alternative to tap water if collected, stored, and filtered properly.

Rainwater pouring over lemons

Is bottled water better for plants?

Do you remember that not all water is created equally? The same holds true for bottled water. While some may be good for your plants, others may actually slow down their growth.

However, bottled water doesn’t contain high levels of chlorine or some of the other chemicals that can be found in municipal water. It also doesn’t have to pass through pipes with accumulated dirt and contaminants.

Generally speaking, bottled water is safe to use for plants. But it can be very expensive to water your plants this way, not to mention all of the plastic that you’d be going through. A cheaper and equally suitable alternative is using filtered tap water which will provide an optimal growing environment for your plants.

Can I boil my garden water instead of filtering it?

If you’ve ever camped out before, you know that you should boil any water that you collect from streams. Boiling water kills potential disease-carrying organisms, including bacteria, viruses, and parasites.

While boiling water is great for creating potable water, it isn’t the most efficient method to use in the garden. Not only would it take a great deal of time and energy to boil the amount of water needed for watering your plants, but you would also need to be able to store and cool it.

Additionally, boiling water for the garden will kill off the organisms living in it, which isn’t a necessary step for the garden. In fact, adding microbial diversity to the soil isn’t necessarily a bad thing. Furthermore, this method won’t remove toxic substances like chlorine, arsenic, and lead.

For most gardens, a water filter will be much more efficient and cost-effective, not to mention that they are designed specifically to improve the quality of the water for your plants.

Well water being collected in a bucket with the text: Should I filter my garden water?

What kind of garden water filter should I buy?

If you’ve tested your water and you’ve discovered that you need a garden water filter, the next logical step is finding one. However, with so many different water filters out on the market, this is easier said than done.

Fortunately for you, we’ve put together a simple yet comprehensive buyer’s guide to help you find the best garden water filtration system for you. When selecting a water filter for your garden or greenhouse, keep the following factors in mind:


The first step in selecting a filtration system that’ll work effectively in your garden is to test your water and find out what needs to be filtered out. Some water filters are designed specifically to reduce chlorine or heavy metals, while others are designed to “soften” the water, etc.

Next, there are a few different types of water filters that range in size, price, and more:

Distillation water filters work by heating the water and gathering the condensed steam so the contaminants are removed. The issue with these filters is that some of the contaminants can turn to gas during the distillation and remain in the water. While water distillers can be great for home use, they tend to be inefficient for the garden.

Reverse osmosis is another type of water filter system. Essentially, this type of filter reverses the flow of the water to filter out the contaminants through a semipermeable membrane. This is an effective method, but it wastes water in the process.

Activated carbon filters are a simpler type of water filter that eliminate impurities through a porous, absorbent filter.

These days, most garden water filters use a combination of methods to properly remove the impurities and contaminants in your water. The most effective filter systems for the garden are two-stage filter systems. These systems remove contaminants, as well as 99% of VOCs, chlorine, pesticides, and other heavy metals.

Another type of filter that is becoming increasingly popular is one that attaches right at the end of your garden hose. These are easy, cheap, and efficient, but they are not as effective at removing all impurities from the water.

Size and capacity

An important factor to consider when choosing a water filter is the size and capacity of the filter. You’ll have to consider your garden or greenhouse size before selecting a water filtration system. Most filter systems will indicate their water-holding capacity on the packaging as well as the amount of garden space they can serve.

You don’t want to buy a filter system meant for a small garden and then set it up for use in a much larger garden. The reason being is, there’ll be so much pressure on the filter system and it won’t last as long as it should.


Before you purchase a garden water filter system, an important consideration is maintenance. Keep in mind that all systems have filters that will eventually wear out and require replacements. You should select water filters that are easy to replace so that maintenance is fast and stress-free.

Reverse osmosis filters have an additional membrane that you’ll need to change every 2 years, but you can make the membrane last up to 3 years by keeping the water pressure at a moderate level.

There are garden water filtration systems that come with additional weather-resistant features that enable the systems to last even longer.

Best all-around garden water filter: GrowMax filtration systems

If you’re looking for an all-around water filtration system designed to eliminate impurities and contaminants from your water so you can get the best out of your plants, GrowMax water filtration systems are a great option for you!

The GrowMax water filtration systems come in different sizes depending on your garden space. There are basically three options: GrowMax Eco Grow 240, GrowMax Water Super Grow 800, and the GrowMax Water Pro Grow 2000. These are ideal for gardens and greenhouses between 96 and 200 sq. ft in size.

The GrowMax filtration system is highly effective at eliminating commonly found impurities such as chlorine, pesticides, heavy metals, and chemicals. All GrowMax systems feature a two-stage filtration system perfect for regular gardens, hydroponics gardens, and greenhouses.

You can easily connect GrowMax to your irrigation system or garden hose to help you supply clean and safe water that’ll help your plants grow to the maximum!

GrowMax Water filtering irrigation water

Special features of the GrowMax garden water filtration systems

  • Effective two-stage filtration systems
  • Water-efficient filtration
  • Quick and easy filter replacement
  • Durable, weather-resistant parts
  • 10,000 gallons to 25,000 gallons to 1ppm chlorine treatment capacity
  • Fast, easy, and direct connection to water irrigation systems
  • Features UV-safe opaque housings that prevent bacterially and algae growth

Do you filter your garden water? Are there other methods you use to purify your garden water? Share your experience in the comments below!
Picture of Jesse James
Jesse James

Jesse James, an Army Veteran, now shares his passion for gardening through engaging articles on Greenhouse Emporium. Leveraging his experience and love for nature, Jesse provides practical advice and inspires others on their gardening journey.

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