Why Get a Garden Water Filter?

Tap and well water can contain contaminants that hurt your garden and soil. Learn about these contaminants and how a garden filter addresses them.

By: Emily Jacobs

Here’s the scenario: you’ve plotted out the perfect backyard garden — or maybe even a homestead. You’ve carefully chosen what you want to grow and bought the right seeds for the time of year and the climate where you live. You’ve researched the soil needs for a bountiful harvest or just the perfect ornamentals to enjoy some gorgeous flowers. You’ve even picked out the optimal places for each plant according to its sunlight needs. All that’s left is the water. But what of that water? Tap should be just fine, shouldn’t it? 

Well. Not always.  

Plants can absorb the trace contaminants in water, which can harm plants just as much as humans and animals and even pass those effects on to humans. 

A number of contaminants can cause plant issues, from acid to pathogens to fertilizer runoff to traces of chlorine and chloramines, all of which absorb into plant roots with the water transporting them. This is because plants’ roots and vascultory systems function somewhat similarly to the human circulatory system: they carry nutrients to the rest of the plant, and those nutrients are transported via the water absorbed by the plants’ roots. So whatever’s in the water going to your plants’ life support systems, your plants will likely be affected by those problems. The concern with this can vary depending on whether you’re growing plants for food or for show. 

So, what impacts do various contaminants have and should you get a garden water filter? Let’s get into it. 

Fertilizer runoff gets into streams

Ironically, one thing polluting your garden might be other peoples’ gardens (though more likely large-scale agricultural productions), in the form of fertilizer runoff. Excess fertilizer that can contain high levels of nitrogen or other nutrients washes into streams and rivers, and can make its way to your green patches. Gardening website Dave’s Garden explains, “Years of U.S. Geological Survey research shows that urban and suburban pesticide application is a significant source of water contamination. The highest level of Imidacloprid detected in California is in urban stormwater.” (Imidacloprid is an insecticide that mimics nicotine, which is fatal for insects.) 

Contaminants and your garden soil

Polluted water doesn’t just affect the plants, it impacts the vitamins held in their soil as well. Specifically, contamination in water can wash nutrients out of the soil. Educational site Sciencing, explains how this happens, saying, “Polluted water in the ground actually washes the essential nutrients plants need out of the soil. Water pollution makes the soil acidic and negatively affects the solubility of nutrient ions, such as iron, magnesium, potassium and calcium ions. As a result, water removes these nutrients more quickly from the soil and sends them into streams and lakes.” The nutrient loss has detrimental effects on your garden. For instance, plants need iron to create chlorophyll and potassium for using water effectively. Without them, plants become more vulnerable to all the typical garden enemies: drought, insects, and infections. 

This can affect the pH of the water, which can in turn affect the health of your plants. Some plants, such as citrus trees and tropical plants, prefer acidic water and can be impacted adversely be highly alkaline water. Throwing off that pH can impact nutrient uptake within plant roots. Meanwhile, highly alkaline water can result in less plant growth as well as lower quality, according to the New Jersey Agricultural Experiment Station at Rutgers University

Water treatment chemicals can affect your garden

Municipalities add chlorine and sometimes other chemicals to their water during the disinfection process to keep public water safe. These get removed before being transported to citizens’ homes, but trace elements often remain in the water supply. Trace chlorine and chlorides leftover from the disinfection process can also be damaging to plants. Chloramines can accumulate in plant leaves and lead to leaf necrosis, which looks like leaf scorching. Chlorine, on the other hand, possesses a less stable molecule, making it easier to remove but also increasing the the potential for it to combine with other trace elements in the water to create something even more unpleasant. 

But it isn’t just the cleaning agency that can impact your garden’s health. Many municipalities also add fluoride to their water, but for plants, even low levels of fluoride can have adverse impacts on a garden. Because fluoride isn’t an essential nutrient for plants, it can accumulate in them over time and even lead to inhibiting photosynthesis. In other words, if you’re looking forward to a strong cucumber harvest, you might be disappointed. 

Plants can pass pathogens on to humans and animals

When a plant’s water is contaminated, that contamination is dispersed throughout the plant, according to Garden Knowhow. That might be less of a concern if you’re growing azaleas or other ornamental plants, but it becomes a bigger one if you’re growing tomatoes, lettuce, peppers, or anything you imagine adding to a salad. In other words, beware when you’re raising edible plants. Eating the spoils of contaminated plants can make a person very ill. This can be a risk depending on where your water comes from — whether it’s a municipality or drawn from a well. Pathogens and microorganisms that cause e. Coli, salmonella, shigella, giardia, listeria, and hepatitis A can find their ways into wells and ponds through rain runoff. So garden filtration is especially key if you’re not drawing your water from your municipality. 

"When a plant’s water is contaminated, that contamination is dispersed throughout the plant."

Water with high total dissolved solids can damage plants

Water often carries high-soluble salts, though that’s different from the ordinary table salt that we know and love. Salts in water refer to the water’s total dissolved solids (or mineral content), which can damage plants and make it difficult for them to grow well at all. Or as UMass Amherst’s Center for Agriculture, Food, and the Environment recently stated, high salt levels “can directly injure roots, interfering with water and nutrient uptake.” In turn, this can lead to nutritional problems within the plant if salts if your plants’ roots absorb those salts instead of the calcium, magnesium, and potassium that plants need. It can also lead to burning of leaf and root tips, harming a beautiful indoor plant.  

Furthermore, the University of Wyoming’s garden newsletter explains that high sodium can also have an adverse effect on the soil, explaining, “Sodic soils form when water with high levels of dissolved sodium evaporates. The sodium left behind can make the soil form a sticky layer water cannot penetrate.” You might even see the results of this hard water in your plants, which UMass Amherst says “can accumulate in plant leaf margins, causing burning of the edges.” 

Why it’s worth using a garden water filter

Whether you’re gardening in a city and using municipal water, or pulling in water from a well or another ground source, your plants will be happiest and healthiest with filtered water. You might start with getting whole house water filter. While whole house filters don’t filter your home’s spigot or sprinkler water, you can always pull water from an inside faucet for watering your garden. One great option is our OptimH2O® Whole House Filter, which filters the water coming out of every faucet inside your home for lead and chlorine as well as PFOA/PFOS and other contaminants. The OptimH2O® Whole House Filter is IAPMO tested and certified to meet NSF/ANSI standards. 

Another option is our Rhino® Whole House filter with the Salt-Free Water Conditioner add-on, which will filter water for one million gallons or ten years.The Salt-Free Water Conditioner helps tackle hard water and dissolved solids, too.  

If houseplants or small gardens are more your speed, there’s the Clean Water Machine, which doesn’t require any installation and is an easy option for filling up your watering can. 

Regardless of what you choose, filtered garden water is the best way to go to ensure healthier, higher yield, more beautiful gardens. 



Tested and certified to reduce lead, cysts, and PFOA/PFOS, plus tackles chlorine and chloramines.