Is Well Water Good for Plants? (The Ultimate Guide)

Choosing the right water source for watering plants will help you to sustain a green, healthy garden.

Here, we’ve looked at well water as a possible water type for your plants, and discussed its benefits and setbacks, compared it to other water sources, and more.

💧 What Is Well Water?

Let’s start with a quick overview of well water.

Well water is groundwater that’s delivered from a water-bearing layer known as an underground aquifer.

Well water varies in composition and quality, depending on local geology. Most well water supplies are naturally filtered, but may contain contaminants that are unique to groundwater sources, such as iron, arsenic, and nitrates.

🌱 Is Well Water Good Or Bad For Plants?

Well water may be good for plants – but it may also be bad for plants. It depends on the water’s pH, hardness and mineral content, and contaminants, as well as the plant’s specific needs.

Let’s look at these in more detail:

• Water pH – Extreme pH levels may be dangerous for your plants. Some plants prefer high pH levels, while others prefer water with a lower pH.
• Water hardness & mineral content – Well water is typically hard, meaning it has a high mineral content. Most garden plants need essential nutrients for healthy growth, but some prefer soft water with a low mineral content and may be damaged by too much calcium.
• Contaminants – Certain contaminants in well water, like nitrates, heavy metals, and pesticides, may harm your plants. Some plants are more tolerant to these contaminants than others, and these contaminants aren’t guaranteed in all well supplies – it depends on your location and geology.

Ultimately, whether well water is good or bad for plants depends on your plants’ specific preferences. For instance, if your plants prefer a certain pH or are less tolerant of certain contaminants, you will need to take this into account when determining the safety of your well supply as a water source.

With that said, unless your well water contains very high concentrations of metals or chemical contaminants, it’s unlikely to have any harmful effects if you use it to water your plants.

🔎 4 Factors To Consider When Using Well Water For Plants

Consider these four factors when using a well supply to water your plants:

Your Well Contaminants

First, consider the different contaminants that your well water might contain.

Certain well water contaminants, like heavy metals (arsenic, cadmium, mercury), salts, nitrates, pesticides, herbicides, some pathogens, and organic matter, can all potentially damage your plants or affect their growth in different ways.

You’ve probably already tested your well water if you use it for drinking. Use these results to determine the suitability of using water from your well on your plants.

The Water pH

Your well water pH may also affect your plants’ ability to thrive, so it’s another factor to consider when deciding whether or not the water is suitable for gardening purposes.

Well water typically has a lower pH level of around 6-7. If your well water has a low pH and the majority of your plants thrive in alkaline soils, watering the plants with slightly acidic water might affect their growth.

Again, you can test your water pH, and you may have done this already. Once you know the results, you can decide whether or not your well water is best for watering plants in your garden.

Your Methods Of Water Treatment

You may already treat your well water to make it suitable for drinking or remove aesthetic contaminants – and some of these treatment methods may make your water less suitable for watering plants.

For example, if you treat your water with a chlorination system, the chlorine content in the water may damage your plant roots and kill good bacteria and microorganisms that are beneficial to your plants.

Or, if you soften your water with a salt-based water softening system, the sodium content in your water could damage your plants with long-term use (although it should be fine in the short term).

👨‍🔧 Learn more: Can I Water My Plants With Soft Water? (Your Questions Answered)

Your Watering Requirements

Finally, it’s also worth considering that using your well supply for irrigation purposes means that you’ll be using more water than if you solely used your well for indoor purposes (showering, drinking, running your water-using appliances, etc.).

This shouldn’t be a problem if you only have a few plants to water several times a week, but if you have a very big garden and a shallow well that’s susceptible to drying out, make sure to be careful of how much water you’re using on your plants during the hot, dry summer months.

Your main priority should be to provide your family with a constant supply of water. If your garden watering demands are too high for your circumstances, you might need to consider another water source.

🚱 Which Well Water Contaminants Are Harmful To Plants?

Here are the well water contaminants that are possibly harmful to plant health:

• Large amounts of calcium carbonate and sodium ions – These could reduce a plant’s ability to absorb other beneficial minerals.
• Iron – Iron is an essential nutrient for plants, but excess iron can lead to plant cell toxicity and make plants lose their pigmentation, hampering their oxygen and food production.
• Heavy metals – Lead, mercury, arsenic, and other heavy metals from groundwater or your well system could have a range of effects, including hindered nutrient absorption, stunted growth, and death of the plant.
• Nitrates (present in fertilizers and human/animal waste) – Large quantities of nitrates may hinder root development, lead to leaf discoloration and have other toxic effects.
• Pesticides/herbicides – While pesticides protect many target plants, they may be harmful to non-target plants and cause chemical plant injury, known as phytotoxicity.
• Microorganisms – Some bacteria and other pathogens are healthy for plants, but others, including many types of fungi, may lead to contaminated soil and cause disease in plants, affecting the leaves, roots, stems, and flowers.

The effects of these contaminants depend on the concentration of contaminants present, and the plant’s own growth preferences and tolerance to these contaminants.

Many of the contaminants on this list are actually beneficial to plant health, and are needed to keep plants alive in small amounts. But there’s a fine line between enough and too much. Very high levels of calcium, nitrate, and iron may have damaging effects.

🆚 Well Water Vs City Water For Plants

Well water and city water have different sources, contain different contaminants and impurities, and have different effects on plants.

Here are some of the biggest differences between well water and city water, and what these mean for plant health.

Source And Treatment

Well water comes from an underground aquifer. The water in the aquifer has filtered through layers of rocks and soils on its journey underground, which acts as natural filtration. Well water isn’t treated (unless you treat it with a whole house water filter).

City water is typically sourced from surface waters aboveground, such as lakes, rivers, and streams. Municipal suppliers treat city water to make it safe for drinking, removing the pollutants that are commonly found in surface sources. Treatment involves filtration and disinfection (usually with chlorine or chloramine).

Well water is usually better than city water for watering plants in this respect because it’s naturally cleaner and doesn’t contain trace levels of chlorine, which is harmful to plants.

Mineral Content

Well water is often rich in natural minerals, which are found in the rocks and soils surrounding the aquifer. These minerals include magnesium, calcium, iron, and potassium, which are beneficial for plant growth (plants need minerals to grow their stems, leaves, and roots).

City water usually contains minerals, too, but because it’s derived from a surface water source, the minerals are naturally present in lower quantities.

That means well water is once again a better option for watering plants because its healthy mineral content is higher.

Contaminants

Well water is less likely than city water to be contaminated by pollutants from runoff, rainfall, and airborne particles. Plus, when water travels underground to a well aquifer, it filters through layers of rock, which removes many potential contaminants. But well water may still contain arsenic and heavy metals, nitrates, pesticides, and other contaminants that could negatively impact plant health and growth.

City water is treated to reduce most contaminants down to trace levels, but this treatment process poses problems of its own. Disinfection with chlorine introduces harsh chemicals to the water, which may inhibit plant growth and damage plant roots.

In this area, both well water and city water may pose a risk to plant health, depending on the contaminants they contain.

pH Levels

Well water has a varied pH that depends on local geology. Typically, well water has a slightly lower pH than city water.

City water typically has a neutral pH of around 7, which is suitable for most plants.

There’s no ideal pH for plants – it depends on your plants’ specific preferences for alkaline or acidic conditions. The suitability of well water vs city water for your plants depends on the pH of these water sources, and the pH your plants prefer.

✅ Benefits Of Well Water For Plants

Here are some of the benefits of well water for plants:

• Consistent & reliable water source – Plants need access to fresh water regularly to stay alive. Well water is a reliable source, even during periods of drought when there’s very little rainfall.
• Natural mineral content – Well water contains calcium, magnesium, and other natural minerals that support plant health.
• Cost-effective – Well water is free to access, so even if you need to water a large garden regularly, you don’t have to worry about your water bill.
• Additive-free – Well water doesn’t contain any additives, like chlorine and other impurities added during municipal water treatment. It’s purer, cleaner, and safer for plants as a result.

⛔️ Potential Setbacks Of Well Water For Plants

Some of the potential setbacks of well water for plants are:

• pH levels might not be optimal for plants – Certain plants can only grow in alkaline or acidic environments. If your well water’s pH isn’t optimal for the plants you’re watering, the plant’s growth rate could be inhibited.
• Cool water may hinder root growth – Water from a well is usually cool, even in summer. While this makes for a refreshing drink on a hot day, cold water will lower soil temperatures, potentially stunting root growth.
• May contain damaging contaminants – Well water isn’t treated like municipal water, so it may contain contaminants in concentrations that are detrimental to plant health.

💀 Can Well Water Kill Plants?

Yes, well water can kill plants if it contains high levels of contaminants that are very dangerous to plant health.

If you live in an industrial or agricultural area, your water is more likely to contain metals, pesticides, and other chemicals that could kill plants.

Some of the contaminants in well water that could kill your plants in large quantities are:

• Nitrates/nitrites
• Iron
• Salts
• Fluoride
• Chlorine (if used to disinfect your well water)

You should notice signs of plant deterioration, including wilting, stunted growth, and browning or yellowing leaves, before your plant dies – so there’s time to resolve the issue before it’s too late.

🚰 How To Determine The Safety Of Well Water For Plants

Many well water contaminants are invisible. So, if you fill a glass with tap water, you won’t be able to see, smell, or taste these contaminants – even if they’re present in dangerous levels.

The safest and most accurate way to determine the safety of your well water for plants is to conduct a water test.

If you use tap water from your well for drinking, you’ve probably already tested your water. But you might want to test again for specific contaminants that may be damaging to your plants.

There are two testing methods available:

1. Laboratory testing
2. DIY at-home testing

A laboratory test is more expensive but provides a more accurate, comprehensive analysis of your water quality. Your local county health department may offer free laboratory testing for certain contaminants.

If you just need to determine the safety of your well supply to water your plants, you might prefer to spend less money on a DIY test kit. This will give you an indication of the contaminants your water contains.

Once you know which contaminants are in your tap water, you can decide whether you need a water filter to remove anything that could damage your plants.

🤔 How To Make Well Water Safer For Your Plants

The best way to make well water safer for your plants is to address the contaminants in your water that could be dangerous.

Here are the best methods of water treatment for common well water contaminants:

• Reverse osmosis filter – A reverse osmosis filter is the most effective method of water treatment available to eliminate chemical and biological contaminants, heavy metals, minerals, and salts. Look for an RO system with a remineralization filter, which adds healthy minerals back into water before you use it on your plants. You might need to install a pre-filter to protect the RO membrane from contaminants in your water supply, like iron.
• Air injection/oxidation filter – Iron, manganese, and hydrogen sulfide are all best treated with an oxidation filter. This water filter system treats contaminated water at its point of entry, supplying your whole home with clean water.
• KDF filter system – A whole house water filter that uses KDF filter media is one of the best ways to target heavy metals in your well water. A multi-stage system might also remove chemical contaminants, further improving your water quality and safety for watering plants.
• UV water purifier – If your well water is susceptible to pathogenic contamination, a UV water purifier is the most effective chemical-free treatment that kills harmful bacteria, viruses, and fungi.

🔚 Final Word

Ultimately, the safety and suitability of well water depend on your local geology, the contaminants the water contains, and your plants’ preferred growing conditions.

If you’ve treated your tap water to make it safe to drink, it probably won’t have any detrimental effects on your plants. But if you’re really concerned, you can test your water and install a suitable water treatment solution to remove certain harmful contaminants.

❔ FAQ

Is well water healthy for plants?

Yes, well water typically supports healthy soil and plant growth because it’s usually higher in calcium, magnesium, and other healthy minerals. However, certain minerals and other well water contaminants may be harmful to plant health. For instance, too much iron, nitrates, harmful bacteria, and agricultural chemicals present in your water could inhibit growth or even lead to plant death.

Is hard well water good for plants?

Yes, hard well water is good for plants because it contains minerals that are beneficial to plant health, like calcium carbonate and magnesium. However, excess minerals are associated with a high pH, and some plants love low-pH water and might be affected by hard alkaline water.

Is it safe to eat vegetables grown with well water?

Yes, it’s safe to eat vegetables grown with well water as long as the water doesn’t contain high levels of contaminants that are toxic to humans or cause diseases.

Is well water with iron good for plants?

Yes, well water with iron is good for plants. Both ferrous iron and ferric iron are absorbed by plants and play an important role in photosynthesis, growth, and respiration in plants. However, only small amounts of iron are needed – so if your water contains high levels of iron, this could damage your plants.

How do you make well water safe for plants?

You can make well water safe for plants by removing any contaminants that might be harmful to plant health, including metals, biological contaminants, and sources of chemical contamination. This can be achieved with an at-home water treatment system (the exact system depends on what you want to remove).

Is well water or rain water better for plants?

You can water your plants with either well water or rainwater, but rainwater tends to be the best option because it’s low in minerals and is unlikely to contain microorganisms (depending on how it’s captured). However, rainwater isn’t as consistent or reliable as well water, especially if you live in a region with a warm, dry climate.