Is Well Water Bad For Plants? (Should You Stop Using It?)

If you have a well on your property, you might be wondering if you can use it to water your garden.  It is especially tempting to use well water on your plants if city water is expensive where you live.

So, is well water bad for plants?  Well water is not necessarily bad for your plants. However, you should test your well water regularly, or use a reverse osmosis filter to clean the water.  Well water can contain excessive amounts of calcium, magnesium, iron, lead, nitrogen, or other chemical contaminants.  This is more likely if you live near an industrial or agricultural area.

Of course, there is some vocabulary to pick up when talking about well water. For example, you may hear the terms hard water, soft water, and reverse osmosis water.

In this article, we’ll take a look at what these terms mean and which types of water are suitable for your garden.  We’ll also look at how to test your well water to see whether it is safe.

Let’s get started.

Is Well Water Bad For Plants?

Well water is not necessarily bad for plants – as long as it is clean and free of disease.

stone well
Well water may be a danger to plants if there are excessive salts or chemicals present.

However, there is the possibility that well water contains contaminants that are bad for plants, such as:

  • Heavy metals
  • Excessive salts and nutrients
  • Diseases

These can harm your plants or you and your family.  As such, it is a good idea to test your well water to see if any of these hazards exist.

Potential Problems With Well Water

There are several potential problems with well water. Testing well water is the only way to know for sure that it is safe (more on this later.)

Testing well water is the only way to know for sure that it is safe.

First, let’s go through some hazards in well water that could harm your plants – or you.

Excessive Iron In Well Water

Iron is a common element found in many municipal (city/town) and private water systems.  The deeper your well is, the more likely that the water has high iron levels (due to prolonged contact with underground rock.)

Elevated levels of iron in your well water will make it taste metallic. Even worse, the water will cause stains.

In some towns with high iron levels in the water system, you can see orange-brown stains on sidewalks. High iron levels in water can also cause the same orange or brown color in sinks and bathtubs.

iron water stain
Water with high levels of iron can cause brown or orange stains on stone, concrete, and porcelain.

Too much iron in your well water can cause problems for plants due to excessive levels of iron. According to the Michigan State University Extension, iron toxicity (caused by too much iron) is more likely in acidic soil (which has a low pH.)

Some plants are also more susceptible to excessive iron than others. According to the University of Massachusetts, marigolds and geraniums are more susceptible to iron toxicity.

It is possible to filter iron out of water from a well. According to the North Dakota State University Extension, a filter with a 10 to 15 micron rating should be sufficient for a from a drilled well.

For more information, check out this article on iron in water from Pennsylvania State University Extension.

Excessive Calcium In Well Water

Water with high levels of calcium will often leave a white, crusty buildup (lime) on faucets and shower heads.

If your well water comes from water that has come in contact with limestone (calcium carbonate) deposits underground, then it is more likely to have elevated levels of calcium.

Water with high levels of calcium (or magnesium) is often called “hard water”.

For more information, check out this article from Wikipedia on hard water.

In contrast, soft water has low levels of calcium (or magnesium).

For more information, check out this article from Wikipedia on soft water.

Too much calcium in your well water can cause problems if you use it to water your plants.

First of all, high levels of calcium can raise the pH of your water, which can harm plants.  This is especially true for plants that prefer acidic soil, such as azaleas and blueberries.

Blueberry plants like a low soil pH (acidic), so excessive calcium in water may not suit them.

Also, excessive calcium levels in your soil can prevent plants from absorbing magnesium and potassium through their roots. This can happen even if there are plenty of these elements in the soil.

Excessive Magnesium In Well Water

In addition to calcium carbonate, your well water may contain magnesium carbonate, which also contributes to “hard water” problems.  As with calcium, too much magnesium in water can contribute to high pH.

Excessive magnesium in soil can also prevent plants from absorbing calcium or potassium through their roots.  So, be careful about watering plants with well water if it has high magnesium levels.

Excessive Lead In Well Water

According to the CDC, lead is rarely found in water naturally.  Instead, it can leach into water from lead pipes or lead solder.

Although newer gasoline has less lead than old gasoline, you could still face lead contamination if you live near an area where old gasoline was spilled.

gasoline pump old
A spill from an old gas station may have leaked lead into the soil.

For more information, check out this article from the CDC on lead in private wells.

According to the Oregon State University, plants do not generally absorb lead into their tissues. However, you can still get lead on the fruit or edible leaves if you use well water on your plants.

To avoid this potential problem, rinse your garden produce before eating, including:

  • Fruits
  • Vegetables
  • Root Crops (such as carrots, potatoes, and beets)
  • Leafy Greens (such as lettuce and spinach)

Excessive Nitrogen or Nitrates In Well Water

If you live near a farm or ranch, your well water could contain excessive levels of nitrogen or nitrates.

For one thing, agricultural runoff from nitrogen-based fertilizers could raise the nitrogen levels in your well water.

Also, runoff from animal manure on a cow or chicken farm could be a source of nitrogen in your well water.

In addition, if your well is too close to a leaking septic or sewage system, you could also see nitrates in your water.

Runoff from farms or manure can lead to high levels of nitrates in your well water.

Excessive nitrogen levels in water can lead to over-fertilization of your plants, which will cause plenty of green growth, at the expense of fruit or flowers.

For more information, check out my article on over fertilizing your plants and my article on low-nitrogen fertilizers.

According to the Penn State University Extension, excessive nitrates in water will encourage algae to grow. This can be a problem if you are using well water in a greenhouse or for a hydroponic or aquaponic system.

You can learn more about algae in my article here.

Chemical Contamination In Well Water

If you live in or near an industrial area, there is a risk of chemical contamination of your well water.  This is especially true if a company is dumping chemicals in local streams or rivers near your home.

Even if there are no active businesses near you, your well water may still be at risk.  For instance, an old underground storage tank, septic system, or sewer may spill chemicals underground or above ground.

This could happen from any number of business, including, such as:

  • Laundromats (detergent or cleaning chemicals)
  • Car washes (soap, detergents, or oil)
  • Gas stations (gasoline, coolant, transmission fluid)

The business may have shut down years ago, but the land may still be contaminated with chemicals.  As a result, any rainwater that washes through the contaminated soil can run into underground streams and end up in your well water.

car wash
Spill from an old car wash may leak chemicals into the soil and eventually into well water.

You may be able to check on the status of nearby land with your state’s Department of Environmental Protection.  For instance, you can check out the Massachusetts DEP website here.

Imbalanced pH Levels In Well Water

If the pH level of your well water is too high (basic) or too low (acidic), then it could cause problems for your plants.  This goes double for plants that are sensitive to pH swings or prefer extreme soil pH.

If you have been using your well water for some time without testing your soil, it might be a good idea to do it. For more information, check out my article on soil testing.

As mentioned earlier, high water pH can be caused by dissolved minerals such as calcium carbonate (lime) and magnesium carbonate (dolomite lime).

calcium carbonate
Excessive lime (calcium carbonate) dissolved in water can cause problems for plants.

Low water pH can be caused by an excess amount of sulfur in the water, which you will be able to sense immediately (it smells like rotten eggs).

If you are concerned about this, it is a good idea to test the pH of your well water.  You can buy a water pH test kit online or at a store, or you can send away your well water to be tested.

To find a water testing lab near you, check out this map from the EPA, which shows water testing labs by state.

For more information, check out this article from the EPA on water testing.

Diseases In Well Water

The threat of disease is a possibility when dealing with well water.  Unlike municipal water systems, your well water is not treated with chlorine or other chemicals that can destroy E. coli or other bacteria and pathogens.

covered well
Untreated well water may harbor disease, so get it tested.

If you suspect that there is disease in your well, don’t spray water directly on your plants, especially the fruit or edible leaves.  Also, avoid watering plants that grow on or in the ground, such as potatoes, carrots, or beets.

For more information, check out this article from the CDC on E. coli in private wells.

How To Test Your Well Water

Now that you know about all of the potential hazards in your well water, it is time to learn how to get testing done.  To get your well water tested, find a water testing lab near you.

Check out this map from the EPA to find water testing labs by state.

It is a good idea to test your well water frequently to avoid using contaminated water.

For more information, check out this article from the CDC on well water testing.

What is Reverse Osmosis Water?

According to Wikipedia, “reverse osmosis is a water purification process that uses a membrane to remove ions from water”.  Essentially, a reverse osmosis filter is removing dissolved particles from water to make it cleaner.

Reverse osmosis can remove dissolved elements and bacteria from water.  For more information, check out this article from Wikipedia on reverse osmosis.

If you want to purify your well water before using it in your home or garden, you can buy your own reverse osmosis water filtration system.  These systems start at about $150, but can be as expensive as $400 or more.

You can check out some reverse osmosis water filter systems at Home Depot’s website.

By removing dissolved elements and bacteria from your well water, it should be safe to use for watering plants or for other purposes in your home.


Now you have a better idea of what to look out for in your well water.  If you have any concerns, you should test your well water before using it on the plants in your garden.

You might also be interested in reading my article on using tap water in your garden.

I hope you found this article helpful – if so, please share it with someone else who can use the information.

If you want to read some of my most popular posts, check out the “Best of GreenUpSide” page here.  Enjoy!



Hi, I'm Jon. Let's solve your gardening problems, spend more time growing, and get the best harvest every year!

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