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Private Well Water Treatment

If bacteria, parasites, and chemicals are in your well water, you can improve the quality of the water with treatment. Learn more about some constituents found in New Mexico private wells (Explore Data).

To make sure your water is safe for drinking, testing is your first step. For more information on testing, including what to test for and where to get water tested, visit our testing page.

When test results show that your drinking water contains contaminants at levels above the safe limit, an appropriate water-treatment system or use of a clean alternative source of drinking water (e.g. bottled water) is recommended. Long term, a more cost-effective solution for homes on private well water may be filtration systems such as a point of use reverse osmosis (RO) system or an ion exchange system.

Talk to water treatment companies and learn the pros and cons of treatment systems. Choose one that best meets your water quality needs by removing or reducing the bacteria and chemicals found in your water. If you decide to purchase a water treatment system, it is recommended that you purchase a unit that is NSF International (or American National Standards Institute (NSF/ANSI) certified. These products are certified, and verified, to reduce a certain contaminant or contaminants (constituents) from the water.


There are different reasons for choosing a treatment system and a single system may not meet all the treatment needs of a well owner. Reasons for selecting a water treatment system may include:
  • Remove something specific from the water such as: metals or bacteria.
  • Protect sensitive household members such as: children, seniors, or those with compromised immunity (like a chronic illness).
  • Improve taste.

Water treatment systems can be for use at a tap or for the whole house, or in combination.
  • Point of Use - at a single tap such as a kitchen faucet (includes pitcher filters).
  • Point of Entry - treats the water entering a home.

Different methods of water treatment can be used to reduce different contaminant types. See the Types and Methods of Water Treatment for more information.

Learn more about private well water quality testing.

After you test your water it is important to understand what the results mean. The table above provides a simple guide to understanding your test results and some treatment options.

For further help understanding test results, use this water quality interpretation tool, from Colorado State University. Choose the US option. The National Groundwater Association also provides more information about interpreting your water test results.

This information can help you select an appropriate water treatment system, if needed. If test results show that your drinking water contains contaminants at levels above the safe limit, you can improve the quality with treatment. An appropriate water-treatment system or use of an alternative source of drinking water, such as bottled water is recommended.

Household Water Treatment

There are many different treatment options for the treatment of well water. No single treatment type will protect against all problems. Many well owners use a home water treatment unit to:

  • Remove something specific from the water such as: metals or bacteria.
  • Protect sensitive household members such as: children, seniors, or those with compromised immunity (such as chronic illness).
  • Improve taste.

Water treatment systems can be for use at a tap or for the whole house, or in combination.

Point of Entry Systems

Point-of-entry systems are typically installed at the water well and treat most of the water entering a home.

Point of Use Systems

Point-of-use systems are systems that treat water at a single tap such as a kitchen faucet (includes pitcher filter).

Many treatment methods are available, the best treatment option may depend on the water chemistry, and contaminants of concern. Provided here is a brief description of common treatment methods. For more information on reducing microorganisms (bacteria), metals (like arsenic and uranium), chemicals (like nitrate) and perfluorinated compounds (PFAS), see sections below.







Filtration


A water filter removes impurities from water when contaminants stick to the surface or in the pores of a filter medium.
  • Filtration may need to be combined with other pre-treatments (such as adjusting pH).
  • Examples of filtration systems include: activated carbon filters (including pitcher filters), and reverse osmosis (RO) systems.
  • Filtration can include different pore sizes, capturing different types of contaminants.
  • Filters can protect against protozoa, bacteria, viruses, and some chemicals.

Water Softeners (Ion Exchange)


Water softeners use ion exchange technology to remove chemicals that have a positive or negative charge (ions).
  • Most frequently used to reduce the amount of hardness (calcium, magnesium) in the water.
  • Some models are also designed to remove other chemicals such as: iron, manganese, heavy metals, some radioactivity, nitrates, arsenic, chromium, selenium, sulfate, and uranium.
  • They do not protect against protozoa, bacteria, and viruses.

Distillation


Distillation systems heat water to the boiling point and then collect the water vapor as it condenses, leaving many of the contaminants behind. Distillation can remove chemicals such as:
  • Arsenic, barium, cadmium, chromium, lead, nitrate, sodium, sulfate, and many organic chemicals.
  • Microorganisms like protozoa, bacteria and viruses.

Ultraviolet (UV) Light


Ultraviolet light is used to disinfect (reduce amount of bacteria or other microorganisms) in water.
  • Often combined with pre-filtration.
  • Reduces microorganisms like protozoa, bacteria and viruses.
  • Not effective at removing chemicals.

Chemical Disinfection


Chemical disinfection can include chlorine, chlorine dioxide, and ozone.
To determine the best treatment option, contact a water treatment system professional. For more guidance see Choosing and Finding Water Treatment section below.

  1. Get the water tested by a third-party water testing laboratory (not the person selling you the equipment).
  2. Educate yourself on the different types of water treatment.
  3. Additional questions to ask:
    1. What maintenance is necessary? (replacement filter cost, can I do it myself, etc.)
    2. Can I throw away used filters in the trash or does it require special disposal?
    3. How much water does it waste?
    4. Will I need to supplement my diet? Can I use a water softener if I have high blood pressure?
    5. What types of things will void my warranty? What does the warranty cover?
  4. Shop around. GET IT ALL IN WRITING! (check with the Better Business Bureau (BBB)).
  5. After installation, test again.

Further guidance to finding products certified to reduce a contaminant, or contaminants and water treatment providers below.
Choose a system verified to do what it says.
  • It is recommended you purchase a unit that is NSF International or American National Standards Institute (NSF/ANSI) standards certified.
  • These products are certified to reduce particular contaminants from the water and have been tested for these claims.

Organizations that provide a way to search for these certified products include:
If you decide to purchase a filtration system, hire a company that has experience in successfully removing toxic chemicals in private domestic well water. Finding such a company can be challenging and finding providers in certain communities can also be challenging. General recommendations for finding a reputable water treatment specialist are below.

The treatment system should be installed by a plumber licensed by the Construction Industries Division of the NM Department of Regulation and Licensing, and you should purchase a maintenance service contract for the system.

Search for water treatment providers in the Water Quality Association Provider search function. Search by company or location.

Various methods can be used to reduce harmful microorganisms, such as bacteria and viruses, in drinking water. Some options include:

Chlorine bleach disinfection:


Boiling water:

  • If your water has tested positive for bacteria, boiling it to kill germs may be a good short-term option.
  • If the water contains other potentially harmful chemicals or constituents, boiling the water may concentrate them.
  • Water should be brought to a rolling boil for 1 minute or 3 minutes for altitudes greater than 6,562 feet.
  • See more detail about boiling water and its uses.

Filtration

  • A water filter physically removes impurities from water, including disease causing microorganisms.
  • Filtration is classified by the pore size, or the size of the hole allowing the water through. Larger size removes fewer types of organisms.
    • Microfiltration (0.1 micron) - removes protozoa (such as: Cryptosporidium, Giardia) and some bacteria.
    • Ultrafiltration (0.01 micron) - removes protozoa, bacteria (such as: Campylobacter, Salmonella, Shigella, E. coli), and some viruses.
    • Nanofiltration (0.001 micron) - removes protozoa, bacteria, viruses (such as: Enteric, Hepatitis A, Norovirus, Rotavirus) and some chemicals.

Reverse Osmosis (RO):

  • Reverse Osmosis is a type of filtration that works by having water pass from a more concentrated solution to a more dilute solution through a semi-permeable membrane. RO systems often include additional filtration.
  • RO systems are fairly small and are usually placed under the kitchen sink (point-of-use).
  • Properly installed and maintained RO systems will remove many contaminants from drinking water.
  • RO can reduce chemicals and microorganisms (like protozoa, bacteria and viruses).

Ultraviolet (UV) Light

  • Ultraviolet light is used to disinfect (reduce the amount of bacteria) in water.
  • Combined with pre-filtration.
  • Effective in removing microorganisms like protozoa, bacteria and viruses.

Distillation

  • Distillation systems heat water to the boiling point and then collect the water vapor as it condenses, leaving many of the contaminants behind.
  • Effective in removing microorganisms like protozoa, bacteria and viruses.

Well water can get contaminated with infected human or animal waste. Common sources are: septic systems, animals such as livestock, and fertilizer (manure). The well can become contaminated after maintenance or a disturbance (like a flood) if the well head is damaged or not properly maintained.

This type of contamination can cause gastro-intestinal problems. Common symptoms include: stomach cramps or pain, diarrhea (sometimes bloody), vomiting, fever, rotten egg smelling diarrhea (giardia).

Learn more about bacteria, viruses, and parasites in private well water..
  • Protect your water source from waterborne pathogens:
    • Keep possible contaminant sources a safe distance from any well. If you live in an area with a high density of private wells, you can be a good steward by not disposing of manure and chemicals on your property and by keeping possible contaminant sources on your property a good distance from the well head on your neighbor's property.
    • Make sure your well has a sanitary cap or seal.
    • Make sure the ground is sloped away from the well so water flows away from the well head.
    • Make sure the casing extends 18 inches above the land surface (NMAC 19.27.4).

  • Prepare when flooding is likely:
    • Use sandbags to divert water away from the well head.
    • Protect any vented areas with tarp or duct tape.

Learn more about protecting private wells before, during, and after disasters.

Different methods can be used to reduce metals, such as arsenic and uranium, in drinking water. Boiling your water will increase, not decrease, metals concentration. Some treatment options include:

Reverse Osmosis (RO):

  • Reverse Osmosis is a type of filtration that works by having water pass from a more concentrated solution to a more dilute solution through a semi-permeable membrane. RO systems often include additional filtration.
  • RO systems are fairly small and are usually placed under the kitchen sink (point-of-use).
  • Properly installed and maintained RO systems will remove many contaminants from drinking water.
  • RO can reduce chemicals and metals such as:
    • Arsenic, fluoride, uranium, radium, nitrate, chromium, lead, copper, sulfate, phosphorous.
    • Sodium, chloride, calcium, magnesium, potassium.

Ion Exchange/Water Softeners:

  • Ion exchange units are typically sold to consumers who want minerals removed from the water to make it less "hard".
  • Some models are also designed to remove other chemicals including:
    • Iron, manganese, heavy metals, some radioactivity, nitrates, arsenic, chromium, selenium, and sulfate.
    • Ion exchange is also an effective method for uranium removal.

Distillation

  • Distillation systems heat water to the boiling point and then collect the water vapor as it condenses, leaving many of the contaminants behind.
  • Distillation can remove chemicals such as:
    • Arsenic, barium, cadmium, chromium, lead, nitrate, sodium, sulfate, and many organic chemicals.

There are different types, brands and dealers of treatment systems. It is recommended that you purchase a unit that is certified to reduce the contaminants such as metals found in your drinking water. For more information see the Choosing and Finding Water Treatment section.

After installing the treatment system, use the treated water (for example: from the RO faucet) for drinking water, cooking, and making coffee, tea, baby formula and ice.
Treatment Options for Removing Aresnic
The Environmental Protection Agency's (EPA) national drinking water standard for arsenic is 10 micrograms per liter (mcg/L). If test results show a concentration of arsenic greater than this amount, treatment or an alternate clean source of drinking water is recommended. Use treated water for all water you drink and cook with, including beverages and food.

The type of treatment will depend on the type of arsenic in the water and other water chemistry. Some options, including reverse osmosis, adsorptive media filter, and distillation are shown in the table above.

If you decide to purchase a reverse osmosis, or other treatment system it is recommended that you purchase a unit that is certified to reduce arsenic. For more information see the Choosing and Finding Water Treatment section to help make a decision of which model to buy.
Possible health concerns from excessive exposure to arsenic typically are associated with long-term exposure to high levels of inorganic arsenic. Long term exposure may cause urinary bladder, lung, and skin cancers.

It may lead to other health problems in some people, such as:
  • Peripheral vascular disease.
  • Peripheral nerves changes (symptoms may initially include numbness in the hands and feet that may progress into a painful sensation of "pins and needles").
  • Liver injury, which may progress to cirrhosis.
  • Skin changes, including pigmentation and hard patches on the palms and soles of the feet, which may lead to skin cancer. Learn more.
If test results show that your drinking water contains more than 30 micrograms per liter (mcg/L) of uranium, an appropriate water-treatment system or use of clean alternative source (e.g. bottled water) of drinking water is recommended.

Point-of-use (at the kitchen sink) reverse-osmosis (RO) treatment units can reduce uranium concentration in drinking water. Properly operated household RO units can remove up to about 90 percent of the uranium from the raw water. It is recommended that you purchase a unit that is NSF International Certified and is effective in filtering radium (Ra-226 and Ra-228).

Other treatment methods, such as distillation and an ion exchange can also reduce uranium concentrations.

After installing a treatment system, use the treated water for drinking water, cooking, and making coffee, tea, baby formula and ice.

It is recommended that you purchase a unit that is certified to reduce the contaminants such as uranium found in your drinking water. For more information see the Choosing and Finding Water Treatment section.
There are some possible health concerns related to the kidney from excessive exposure to uranium. The kidney is the most sensitive organ for uranium toxicity. Some studies have shown small changes in the way kidneys work when people drink water with large amounts of uranium for a long time (usually more than 2-5 years). These changes, however, seem to go away when people stop drinking this water with high-levels of uranium. Learn more.

The Environmental Protection Agency's (EPA) national drinking water standard for nitrate of is 10 milligrams per liter (mg/L). If test results show a concentration of nitrate greater than this amount, treatment or an alternate clean source of drinking water is recommended. Use treated water for all water you drink and cook with, including beverages and food.

Nitrate toxicity could cause illness, with the most vulnerable population being infants. Infants below four months who drink water containing nitrate above 10 mg/L could become seriously ill with blue baby syndrome (methemoglobinemia). Symptoms of this nitrate toxicity include shortness of breath and bluish skin coloring.

Some options for reducing nitrate in water include reverse osmosis, ion exchange, and distillation.

It is recommended that you purchase a unit that is certified to reduce the contaminants such as nitrate found in your drinking water. For more information see the Choosing and Finding Water Treatment section.
Nitrogen is essential for all living things, but high levels of nitrate in drinking water can be dangerous to health.

Sources of nitrates in drinking water can include runoff from fertilizer use; leaking from septic tanks, sewage; and erosion of natural deposits.

Nitrate toxicity could cause illness, with the most vulnerable population being infants. Infants below four months who drink water containing nitrate above 10 mg/L could become seriously ill with blue baby syndrome (methemoglobinemia). Symptoms of this nitrate toxicity include shortness of breath and bluish skin coloring.

Learn more.

Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals, including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), and are known as the "forever chemical". PFAS persist in the environment and move through soil and can contaminate groundwater and have potential for accumulation in the food chain and human body. These chemicals have been widely used for decades in consumer and industrial products to make them non-stick and water resistant. They are found in firefighting foams, protective or stain resistant coatings for fabrics and carpets, paper coatings, insecticide formulations, paints and cosmetics. PFAS can persist in the environment and move through soil and contaminate groundwater.
People served by a community water system (or municipal water supply) should contact their local water authority with questions about PFAS in their drinking water.

People who have private wells should get their water tested. Learn more about testing private well water. Ideally, people would not have any PFAS in their drinking water. People who have private wells with PFAS should consider using other sources of drinking water. Other sources of drinking water include water treated under the sink by a properly designed and maintained filtration system or bottled water.
Certain household filtration systems can remove these compounds from drinking water. If you decide to purchase a treatment system, hire a company that has experience in successfully removing toxic chemicals in private domestic well water. The system should be installed by a licensed plumber, and you should purchase a maintenance service contract for the system. Boiling does not remove Per- and Polyfluoroalkyl Substances (PFAS).

A list of water treatment options for removal of perfluorooctanoic acid (PFOA) and perflurooctane sulfonate (PFOS) can be found in the table below. Learn more about possible techniques and methods for the removal of PFAS in groundwater.

The healthiest thing you can do is lower exposure to these compounds. If exposure is from drinking water from a private well, there are treatment options designed to help reduce exposure by removing PFAS from the water.

There are some considerations when choosing a treatment system for PFCs/PFAS:

  • Boiling your water will not remove perfluorinated compounds from drinking water.
  • Reverse osmosis systems (if installed and maintained properly) can be more than 90 percent effective at removing a range of PFAS compounds (see table below for a list of water treatment options for removal of PFOA and PFOS). This treatment system does generate some waste water, therefore, a point-of-use system (under the sink) is recommended as the amount of waste water produced will be less than with a whole house system. Further, this type of water treatment system can generate a waste containing high concentrations of removed chemicals present in the water supply. Therefore, proper or safe disposal of such waste should be considered and planned for.
  • The treatment option should be certified (to meet the American National Standards Institute (ANSI) standards) to reduce the contaminant of concern below the EPA health advisory level. Find certified treatment options through NSF International (1 800 673 8010) or the Water Quality Association (630-505-0160).

    Treatment Type Notes Application PFOA Removal Rates PFOS Removal Rates
    Membrane Filtration (Reverse Osmosis (RO) and Nanofiltration) Multi-contaminant removal. Waste/by-products must be managed. Mineral addition may be necessary. Households (RO), Groundwater, Surface Water, Public Water Systems >90% >90%
    Granular Activated Carbon(GAC) GAC is the most common treatment method for PFAS removal. Presence of other organic compounds may reduce effectiveness. Households, Groundwater, Surface Water, Public Water Systems >90% >90%
    Powdered Activated Carbon(PAC) High concentrations of PAC are necessary. Required high concentrations may make this an infeasible option for water treatment. Waste residuals may create a challenge for disposal of waste products. Households, Groundwater, Surface Water, Public Water Systems >90% >90%
    Anion Exchange Single-use systems require replacement and proper disposal. Regenerable systems produce brine that must be disposed of responsibly; such systems are automated, have small footprints and high regeneration efficiencies. Competition with naturally occurring minerals can impact effectiveness. Groundwater, Surface Water 10-90% >90%
    Advanced Oxidation (UV/H2O2; UV/S2O8) Low removal rate. Can destroy pollutants to produce less complex compounds. Other organic contaminants will reduce efficiency. Groundwater, Surface Water <10% <10-50%

    Note: adapted from: National Ground Water Association (NGWA) document: Groundwater and PFAS: State of Knowledge and Practice (member available document). Table Source: Cheremisinoff , N. P. 2016. Overview of Water Treatment Technology Options in: Perfluorinated Chemicals (PFCs): Contaminants of Concern. Scrivener Publishing. Beverly, MA. ISBN 978-1-19-36353-8.

  • If you decide to purchase a filtration system, hire a company that has experience in successfully removing toxic chemicals in private domestic well water. The treatment system should be installed by a plumber licensed by the Construction Industries Division of the N.M. Department of Regulation and Licensing, and you should purchase a maintenance service contract for the system.
The EPA develops health advisories (HAs), which are not for regulation, to give information about compounds that can cause harmful human health effects and can occur in drinking water. An HA includes the level of the compound that is considered safe in water, taking into account exposure to food. To provide residents, including the most sensitive people, such as pregnant women, with a margin of protection from exposure to specific perfluorinated compounds (PFOA and PFOS) in drinking water, EPA established health advisory levels for both PFOA and PFOS at 70 parts per trillion (ppt) or nanograms per liter (ng/L). To say it another way, 70 drops of PFOA and PFOS in an Olympic-size swimming pool (660,000 gallons of water) is equal to the health advisory. This means even these small amounts of PFAS may be harmful. Many states developed or are in the process of developing drinking water action levels or guidelines for PFAS below EPA's HA of 70 ppt and include more compounds than PFOS and PFOA. More information about other states' regulations can be found here: https://www.asdwa.org/pfas/.

Ideally, people would not have any PFAS in their drinking water. When PFAS are found in drinking water, the combined concentrations should be compared with the health advisory level. When levels of PFAS in water are higher than the EPA health advisory level, action should be taken to protect humans from eating or drinking the compounds. These actions could be taken by a water company changing how sources of water are blended or by the consumer using treated or bottled water. A health advisory value is not a clear line between levels that cause health effects and those that do not.

Learn more about per- and polyfluoroalkyl substances (PFAS) and your health.
As a well owner you can take many actions to help protect your water source including: learning about water quality and, if needed improving it through treatment; through water conservation; well maintenance; and, (if your household also has a septic system) septic maintenance.

Protect your well water by keeping potential contamination sources at a safe distance:
  • at least 50 feet- existing wells (including on another property).
  • at east 100 feet- septic tanks, leach fields, silos septic, and livestock yards.
  • at least 200 feet- manure storage, pesticide and fertilizer storage or handling, and petroleum tanks.
  • greater than 200 feet- manure stacks.

Learn more about protecting water quality and private well water sources (Protecting Your Water Source).
Floods, earthquakes and other disasters can damage or contaminate wells. If your well water has been contaminated or you suspect that it may be contaminated, do not drink the water. You need to properly disinfect or treat the water and have it tested before drinking/using the water. Drink clean water from another source until you are sure the water from your well is safe to drink again.

Learn more about protecting your well and water quality before, during and after disasters.
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Content updated: Thu, 4 Jun 2020 16:26:02 MDT