By Gary L. Hix, R.G., CWD/PI

Have you ever asked yourself: “Does my well water need treatment?” The question is not one you can answer if you have not had your water tested recently. You should ask yourself instead: “When was the last time I had my water tested?” If the answer to this question is never or a long time ago, it’s time to do it, or do it again.

A well owner preparing to sample her well water for testing

A well owner preparing to sample her well water for testing

NGWA and many other agencies constantly encourage all private well owners to test their water quality periodically to protect themselves and their family. Despite their efforts, many private well owners have never had their water tested. If they have, it may have been for nothing more than the presence or absence of coliform bacteria. This test alone is not enough to accurately answer your first question. Your next question should be: “What should I have my water tested for?”


The amount of water testing a person would recommend will vary, but never as much as public water systems are mandated to be tested for by the EPA. Most of us agree—without regulations or specific guidance from state or local governments—we can reasonably suggest private well owners test their water yearly for coliform bacteria, total dissolved solids, pH, nitrite, nitrate, and fluoride.


In addition, test your water once every five to ten years for arsenic, uranium, mercury, radon—and in some areas, perform a pesticide screen. There are many other elements I could recommend testing for in specific areas of the country.

You must keep in mind that no single treatment can remove all contaminants that might be in your well water. Depending on your water quality test results, you may have to remove more than one contaminant. If you do, you may need to combine several treatment devices into a single treatment system.

The following is a step-by-step question and answer procedure to guide a well owner in deciding if they need water treatment and what kind. The four-step question and answer sequence can guide a well owner in selecting their most likely treatment processes. If you are not attempting to install the necessary water treatment equipment yourself (not recommended), then you will at least know what processes the water treatment expert should be offering you.


Iron color in your water means it needs treatment

Iron color in your water means it needs treatment


1. Is the water cloudy, tan, or rust colored?

Is there any visible sediment in the water? Does that sediment quickly settle to the bottom of a glass or does it take hours to settle? Does the color or sediment settle downward or upward? Does your water have a light milky color, a light tan or rusty color? Yes or no? If you answered yes to any of these questions, your water needs some form of filtration.

The size and type of filtration will vary, depending on the composition of what’s making the water appear as anything but crystal clear. It can be residual bentonite, natural clays, organic particles, or dissolved iron in the water. Whatever it is, filtration is the first step to consider if your answer was yes.

Filter Application Guide

Filter Application Guide

Filtration can mean many things to different people, but keep in mind if something is filtered out of the water, it must be either removed from the filter or the filter replaced when it is full. The size of filter pores can range from hundreds of microns to one thousandths of a micron. Most water filters will be in a few tens of microns ranging from 50 down to 10. Selecting too small a filter size will require more frequent replacements.

If your answer to question 1 was no, then go on to question 2.

2. Does the water chemistry report show there is an excess of minerals or elements in the water that need to be removed?

If the report indicated excessive hardness, pH, iron, or other metals, you would need to add chemical treatment, water softeners, or pH adjustment. Treatment is needed if your water has a bad taste or smell or is excessively corrosive.

If your answer is yes, then you must seek water treatment equipment to soften the water to make it easier to treat efficiently. If your answer is no, then proceed to question 3.


3. Does the chemistry report indicate that the water is high in dissolved solids, harmful metals such as arsenic, or trace organics?

If your answer is yes, then you will probably need to perform reverse osmosis, iron filtration, and/or use activated carbon to clean up your water. Activated carbon filtration is often added after reverse osmosis treatment to “polish” the water of any remaining trace organics.

Keep in mind that reverse osmosis treatment systems are more effective operating at higher water pressures. If your well system is working at a minimal 20-40 PSI, you may be wasting considerable amounts of water keeping the RO filter membrane flushed.

If your answer to the question was no, proceed to question 4.


4. Does the water need disinfection?

After all required water treatment methods have been answered yes we do or no we don’t need one of the above steps, then the final treatment to be considered is disinfection.

Because water treatment can sometimes be a slow or low flow process, there will probably be a container to hold the treated water for later use. Anytime stored water is allowed to stand, it has the potential to grow microorganisms. Therefore, water disinfection is applied last. It is typically done through chemical chlorination or ultraviolet radiation.

The answer to this question might always be a yes, especially if your well water is treated and/or stored before use.

Now you must ask yourself one additional question: “How much water do I need to treat?”

Confirm the total gallons of water you need in a day. Most water treatment equipment can be rated in the number of gallons per day they can process—so it is very important to get this number right. One has to be careful when assembling components of a water treatment system to assure their flow-through capacities are compatible.

There is usually no need to treat well water used strictly for outdoor irrigation. There may be some cases where well water with a contaminant such as uranium or some man-made contaminants should not be applied to irrigation of food crops in a garden.

For some applications, under-the-sink RO units can supply a sufficient supply of treated water for household needs. I suggest you ask a water treatment professional for advice on this issue.


Water Treatment Sequence

Water Treatment Sequence


In other instances, a whole house water treatment system may be needed. This sort of system might be placed near the pressure tank for convenience and protection, or it may need to be placed in the basement or an ante-room to the house. Getting advice from a water treatment professional is recommended for making this very important decision.

Once you have worked your way through these questions and have made your decision about the need for treatment of your well water, you’ve just begun protecting yourself and your family.

Now it’s time for the next question: “How often do I need to check the operation of my water treatment equipment?”

Let’s leave the answer to that one for another time.

A water treatment system on a private well

A water treatment system on a private well



About the AuthorGary L. Hix, R.G., CWD/PI

Gary Hix is a Registered Professional Geologist in Arizona, specializing in hydrogeology. He was the 2019 William A. McEllhiney Distinguished Lecturer for The Groundwater Foundation. He is a former licensed water well drilling contractor and remains actively involved in the National Ground Water Association and Arizona Water Well Association.

To learn more about Gary’s work, go to His eBooks, “Domestic Water Wells in Arizona: A Guide for Realtors and Mortgage Lenders” and “Shared Water Wells in Arizona,” are available on Amazon.