Is Well Water Safe to Drink?

If you’re buying a house with a well, you’ve discovered an old well in your garden, or you’re simply considering installing a well at your property, you might have some questions about the quality of well water.

A few hundred years ago, it was pretty standard for people to get their water from a private well. There were no large-scale water treatment facilities making sure that public water was safe. People had to fend for themselves, and that meant drinking their own – usually untreated – well water.

We’ve come a long way since then, but many of us still prefer the freedom and reassurance of capturing and treating water from a private well. But is well water safe to drink? The answer is no, not usually.

Unlike municipal water, well water is completely natural and untreated. Well water isn’t regulated by the Environmental Protection Agency (EPA), and private wells often contain dangerous contaminants that could make you sick.

In this guide, I’ll be sharing the possible problems with well water, and how pollutants and contaminants could affect your well. I’ll also look at how to know that your well water is safe to drink, and which water treatment options are best for wells.

๐Ÿ›‘ What Are the Possible Problems With Well Water?

The most common problems with well water are harmful contaminants, aesthetic issues, and problems with plumbing and appliances.

Harmful Contaminants

According to the EPA, some of the harmful contaminants commonly found in US well water include microorganisms like coliform bacteria and parasites, chemicals like nitrate and nitrite, heavy metals like arsenic and lead, organic chemicals from pesticides and herbicides, radioactive elements like radium and uranium, and minerals like fluoride.

In small amounts, these contaminants aren’t typically a threat to human health. But, depending on the location of the well, a well water source could contain double, triple, or even quadruple the amount of harmful contaminants than the EPA’s standards for public drinking water sources.

Large quantities of harmful contaminants could cause an instant reaction, or these contaminants could build up in your body over time, resulting in long-term illness. For instance, heavy metals like lead are cumulative toxicants, which means they build up quickly in the body and are released at a much slower rate.

arsenic in groundwater map
Source:ย United States Geological Survey (

Aesthetic Issues

You might think that well water would have far fewer aesthetic issues than a public drinking water supply because it hasn’t been treated with chlorine. However, there are several aesthetic contaminants that are particularly common in well water, and can affect the taste, smell, and color of water.

Iron is an aesthetic contaminant you’re likely to find in well water. Iron gives water a brownish-orange tinge and a metallic taste. Depending on the type of iron present, you may notice flecks of rust in your water. Hydrogen sulfide, or sulfur, is another problem aesthetic contaminant in well water systems, and can give water a distinct rotten egg odor and smell.

Aesthetic contaminants aren’t usually dangerous to health, but they can make water look, taste, and smell so unpleasant that you don’t want to drink your water at all. You may end up using bottled water – or using less well water for drinking, which could mean you’re not hydrating your body with the fluids it needs.

Plumbing & Appliances

Finally, a number of contaminants, including the aesthetic contaminants mentioned above, can affect your water quality and damage your plumbing and appliances.

Iron doesn’t only give water a strange color and bad taste. When it interacts with oxygen in the air, iron leaves reddish-orange deposits on surfaces, known as rust. Rust is very difficult to remove, and may eventually corrode surfaces that can’t be reached easily, such as the inside of your pipes or the back of your appliances.

When iron and bacteria are present in well water, the two contaminants can merge into a slimy substance known as iron bacteria. This substance clogs pipes and creates resistance, slowing water flow through your home.

Plumbing and appliances can also be damaged by high levels of hardness minerals in well water. A USGS study of 2,100 domestic wells across the US found that the vast majority of these wells had hardness levels of more than 180 milligrams per liter (Mg/L).

Map detailing hardness of groundwater from domestic wells
Source: United States Geological Survey (

Hard water has a pleasant mineral taste, but too many of these minerals can form surface deposits called scale. When scale builds up on pipes and in appliances over time, it can affect water flow, reduce the efficiency of appliances like hot water heaters, and cause unattractive staining.

๐Ÿšฑ How Do Contaminants & Pollutants Get Into My Drinking Water Well?

There are several ways that contaminants and pollutants can get into private well water systems:

  • From surface runoff, such as from rainfall or snow melt, seeping underground, or washing contaminants into the well system (bacteria, heavy metals, and chemicals can all enter well water this way).
  • Through spills and improper waste disposal, which contaminate the local environment (organic chemicals like pesticides and herbicides often enter well water systems from spills).
  • From human activities like mining and power production (radionuclides can enter well water through these methods).
  • Through septic tank leakage, especially if a well is incorrectly positioned too close to a septic tank (coliform bacteria like E. Coli and other microorganisms can enter a private well in this manner).
  • Natural contamination from the earth (for instance, fluoride, manganese and iron are found naturally in many well aquifers).

โ˜ฃ๏ธ Natural vs Unnatural Contaminants

Some well water contaminants are natural, which means they’re naturally found in the earth or rocks surrounding the well aquifer. Other well water contaminants are unnatural, meaning they’re manmade, or they’re natural contaminants that are released by humans in large quantities into the environment, giving them an unnatural presence in the land.

Some examples of natural contaminants are:

  • Hardness minerals (calcium and magnesium)
  • Iron
  • Sulfur
  • Manganese
  • Tannins
  • Sodium
Limescale Buildup
Calcium and Magnesium Build-Up in Water Pipe

Unnatural contaminants include:

  • PFOA and PFOS
  • Volatile organic compounds (VOCs)
  • BPA and BPS
  • Lead
  • Nitrate/nitrite
  • Pesticides and herbicides
Herbicide water contamination
Herbicide spraying can cause water contamination

Contaminants that are both natural and unnatural include:

  • Arsenic
  • Fluoride
  • Radionuclides
  • Microorganisms like coliform bacteria and viruses
  • Chromium
  • Aluminum

Don’t be deceived: natural contaminants aren’t automatically safe to drink, despite their harmless-sounding name. Some regions have dangerously high levels of natural contaminants. For instance, arsenic, a cancer-causing contaminant, is found in very high levels in California’s groundwater, due to natural arsenic sources in the ground.

The health effects of drinking water from a private well can vary widely depending on the well water quality. Below, I’ve listed some common health effects associated with well water, and which contaminants cause these effects.

Gastrointestinal Illness – Microorganisms Like Bacteria

Gastrointestinal illnesses, characterized by vomiting, diarrhea, abdominal discomfort, loss of appetite, and nausea, are most commonly caused by drinking water contaminated with microorganisms like harmful bacteria (e.g. E. Coli). Symptoms take between 1 hour and 3 days to present themselves after drinking bacteria-contaminated water. Gastrointestinal illness typically lasts up to 10 days.

Bacteria growth in water sample

Cancer – Arsenic and Radionuclides

Heavy metals like arsenic and radionuclides like radium have been linked to cancer when consumed in drinking water. According to, arsenic is linked to an increased risk of skin cancer and bladder cancer.

Internal Organ Damage – Lead

Many contaminants in well water cause internal organ damage in large quantities. Contaminants that accumulate in the body over time, like lead, are most likely to damage the organs if consumed in ground water from a well over a period of years or decades. The kidney, liver, and intestines are particularly susceptible to damage from lead.

Skeletal Fluorosis – Fluoride

Skeletal fluorosis causes weakened, painful bones, and is the result of an accumulation of fluoride in the body. Fluoride is added to many public drinking water sources, and skeletal fluorosis is an unlikely consequence of drinking measured amounts of fluoride in water. However, high levels of fluoride aren’t safe to drink because of the fluorosis risk.

Person suffering from weakened, painful bones

Neurological Disorders – Heavy Metals, PFOS and PFOA, Pesticides

Neurological disorders are caused by drinking water containing high levels of heavy metals (like lead and arsenic), perfluorinated substances (like PFOS and PFOA), and certain types of pesticides. These contaminants can interfere with brain development in a number of ways and can cause memory problems, issues with processing information, and strokes.

Reproductive Problems – Pesticides, Organic Solvents, Heavy Metals

Reproductive problems and even infertility are caused by a number of common well water contaminants, including pesticides, organic solvents, and heavy metals. Exposure to these contaminants in the environment, including in drinking water, has been associated with low sperm count and difficulty conceiving.

๐Ÿ”Ž How to Tell If Your Well Water Is Safe to Drink?

Knowing whether your water is safe to drink can be tricky. Unfortunately, the presence of contaminants doesn’t always present an obvious red flag, like an unpleasant taste or unusual color.

In fact, most chemicals, metals, and microorganisms in water have no color, odor, or smell, so you won’t be able to tell if your water is safe to drink by sniffing it, looking at it, or tasting it.

Often, the best way to tell if your water is safe to drink is to observe how you feel after drinking the water. I don’t recommend this, however, as this sort of experiment could make you sick.

The safest way to tell if your water is safe to drink is to arrange for water testing.

water testing with tap score

Signs Your Water is Making You Sick

Some of the signs your water is making you sick include:

  • Nausea
  • Vomiting
  • Fever/temperature
  • Stomach cramping
  • Diarrhea
  • Brain fog
  • Lethargy
  • Weakness
  • Muscle problems
  • Skin conditions

If you notice any of these symptoms in yourself or a family member, and they can’t be associated with an explanation (such as a viral sickness bug), stop drinking your well water and get it tested immediately.

๐Ÿงช Should I Have My Private Well Water Tested?

If you’ve never tested your well water at all, or it’s been a few years since you’ve carried out well water testing, you need to get your well tested as soon as possible for a broad range of drinking water contaminants. This will tell you exactly what your water contains.

Even after initial testing, you should get your private well water tested regularly for specific contaminants because your local geology can change from time to time, and new contaminants can be introduced to your well aquifer without changing the water quality.

What Should I Test For?

I recommend carrying out comprehensive well water testing for the following contaminants:

  • Hardness and alkalinity
  • Aluminum
  • Arsenic
  • Chromium
  • Copper
  • Barium
  • Lead
  • Iron
  • Mercury
  • Manganese
  • Nickel
  • Silver
  • Potassium
  • Zinc
  • Titanium
  • Sodium
  • Total coliform bacteria
  • Fluoride
  • Nitrate
  • Chloride
  • Sulfate
  • Pesticides
  • Herbicides
  • Total dissolved solids (TDS)

Many water testing laboratories provide testing packages for well water that allows for testing of all these contaminants at a discounted price.

Additional contaminants to test for, if you believe you may have a local pollution issue or you just want to be certain of what your well contains, include:

  • VOCs
  • Radionuclides
  • SVOCs
completed tap score water test

When Should I Test?

If you’ve never had your well tested before, or you’re moving into a new home with a well, get your water tested as soon as possible.

According to the CDC, after initial testing, you should get your well tested every one year for total dissolved solids, nitrates, coliform bacteria, and alkalinity.

There are other occasions, aside from regular testing, when you should get your well tested:

  • When you carry out a repair or replacement in your well system
  • If you’re alerted that your local ground water has been polluted
  • If local land disturbances or flooding have potentially contaminated your well
  • If your water quality (such as taste, odor, or color) has changed

Who Should Carry Out the Testing?

Before you consider private testing, contact your local health department. In some cases, your local health department will test private wells in the area for free, or at a discounted price.

Local health departments will typically test for nitrates, bacteria, pH, and volatile organic compounds. If you’re looking for more thorough testing than offered by your local health department, look into private testing by a state-certified laboratory.

The EPA has a list of state-certified laboratories that allows you to search for laboratories based on where you live.

I recommend Tap Score, a health services company founded at the University of California in Berkeley, which offers three tiers of well water testing depending on the contaminants you need to test for.

water testing with tap score

๐ŸŒ€ How Can I Treat My Well Water?

The most effective water treatment methods for private wells are water filters and disinfection systems.

Filtration Systems

There are tens of water filtration systems available today. The most common of these systems are listed below.

Whole House Systems

Whole house water filters use a combination of filter media to remove a range of contaminants from private wells. A whole house filtration system may use filter cartridges, such as activated carbon filters, or a mineral oxidation process, like air injection, to remove iron, sulfur, manganese, heavy metals, organic chemicals, and other dissolved minerals.

Whole house filters trap contaminants in their media or resin. Depending on the type of water filtration system m you buy, you’ll need to replace the filters or set the unit to regenerate when the media or resin becomes saturated with contaminants.

You can learn more about whole house water filters in my best well water filtration system guide.

Springwell whole house water filter system
Springwell Whole House Water Filter System

Water Softeners

Unlike whole house water filtration systems, water softeners don’t filter contaminants out of water. Instead, these systems use ion exchange to replace hardness minerals with equal amounts of sodium ions.

A water softener is primarily used to tackle water hardness, although some systems can be used for iron removal, too.

If you don’t want to alter the taste of your water, consider a water conditioner. Water conditioners don’t change your water quality. Instead, they alter the composition of hardness minerals, preventing them from forming scale without actually softening your water supply.

Learn more about the best water softeners for well water in my dedicated guide.

Reverse Osmosis

Reverse osmosis systems remove more contaminants than the average whole-house water filter. The design of a reverse osmosis water filter enables it to trap contaminants of all sizes, allowing only tiny water particles to pass through.

All reverse osmosis filters come with several filtration stages, including a carbon water filter, a pre-filter, and a semi-permeable membrane. This membrane is made up of thousands of tiny pores, which deflect contaminants in water flowing through the system. These contaminants are then sent down a drainpipe with a small amount of wastewater.

Point-of-use RO water filters, such as under-sink RO filters, are more common than whole-home filters. For this reason, reverse osmosis isn’t ideal if you want to remove aesthetic contaminants from your water before they can damage your plumbing and appliances.

With that said, whole house RO filtration is becoming more commonplace nowadays. I’ve shared the top whole house reverse osmosis water filters in this guide.

RO system on counter with dedicated faucet
POU Reverse Osmosis System

Disinfection Systems

The aim of disinfection is to make well water safe for drinking by removing microorganisms like bacteria and viruses from the water supply. Disinfection can only be used to kill or remove live organisms in water, and can’t be used to remove impurities like metals and chemicals.

You can find two popular disinfection options below.

Chemical Treatment

Chemical treatment mimics the disinfection process that takes place in large-scale public water treatment facilities.

Chemical treatment systems inject measured amounts of chemicals like chlorine into an untreated well water supply. This water is stored in a tank to allow the chemicals time to take effect before being delivered around your home.

Chemical treatment requires ongoing maintenance because the chemicals will eventually run out, and will need to be topped up every few months. This form of disinfection also involves adding chemicals to water, and comes with an element of risk.

UV Treatment

UV treatment is a low-maintenance alternative to chemical treatment. A UV purification system uses ultraviolet light to alter the DNA of disease-causing pathogens, killing them and preventing them from reproducing.

You can install a UV lamp at your home’s point of entry. When water flows through the chamber, the ultraviolet light provides instant disinfection. UV lamps are space-saving, taking up a fraction of the space that a chemical injection system would need.

Most UV lamps need replacing after one year of use, but some can last for up to three years before a replacement is needed.

whole house uv water filter
Viqua UV Treatment System Diagram

๐Ÿ“‹ Identifying the Best Treatment Method For Your Unique Situation

Once you know more about your water quality, you can decide on which treatment method is most suitable for your well water system.

To decide on a water treatment method, follow the steps outlined below:

1. Assess your water test results

Test your well and look through your test results. Decide which impurities are most concerning in your drinking water, which have the biggest effect on your water quality, and which you’d like to remove. You may decide at this stage that you need several treatment systems (for instance, you want to tackle hard water and heavy metals with a water softener and a whole house filtration system).

2. Consider your water usage

Once you have a list of contaminants that you want to remove, work out how much water you use on a weekly basis. The easiest way to do this is to view your monthly water bill and work out an average based on several bills. It’s important to choose the right system capacity for your drinking water (and washing water, cooking water, etc.) needs, so make sure you select a system that delivers the right amount of water to your home.

3. Consider your water pressure and flow rate

Finally, a water system shouldn’t have a noticeable effect on water’s flow rate in your home. Your water pressure should be adequate enough to still be able to provide instant water to your faucets and appliances, even with a water filter intercepting your waterline. Make sure the filter itself won’t slow down your water flow too much. Customer reviews can be helpful in letting you know how a system affects flow rate.

4. Combine these considerations to find the best water system

Finally, compile what you know about your water quality, water usage, required water pressure and flow rate, and use this data to find a water system that meets all of your requirements.

๐Ÿ’ก Frequently Asked Questions

How long does it take to receive well water test results?

If you test your well with a private testing company, it can take up to 7 days to receive your test results. Most companies will email your results directly to your inbox, but some will post your results if that suits you better.

How can I prevent my private well from being polluted or contaminated?

Unfortunately, you can’t always prevent ground water contamination. However, there are several things you can do on your own property to prevent major drinking water quality issues:

  • Make sure septic systems are installed at least 50 feet away from the well
  • Make sure silos and livestock septic systems are installed at least 50 feet away from the well
  • Keep pesticide and herbicide storage, or petroleum storage, at least 100 feet away from the well
  • Keep manure stacks at least 250 feet away from the well
Required distance of well water from septic tank
Source: Mississippi State University Extension

What is the best treatment for ground water?

The best treatment for ground water depends on your water quality and parameters. Generally, well owners find that a combination of a drinking water filter system and a disinfection system is best. Some well owners may also need to soften their drinking water with a softening system.

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