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Get Informed | Alkalinity

What is Alkalinity?

Alkalinity is the water's capacity to resist changes in pH that would make the water more acidic. It is also the protector of your health and piping when it comes to drinking water.

Some individuals confuse the alkalinity of water with water pH or with water Hardness. These parameters are related, but alkalinity is not the same as pH or Hardness. Alkalinity is determined by slowly adding acid to the water and carefully noting how much acid can be added before the pH starts to change (titration). Calcium carbonate is a very common compound which, when dissolved in water, will add alkalinity to the water.

In order to simplify the reporting of alkalinity, the effect of other compounds such as iron and manganese on alkalinity is compared to that of calcium carbonate to see how much calcium carbonate would be needed to have the same effect. The alkalinity of water is then commonly reported as calcium carbonate equivalent or mg of CaCO3/L equivalent. Because of the units, many think alkalinity is the same as the water Hardness; it is not.

The Hardness of the water is the sum of the concentrations of positively-charged ions (cations) with more than one positive charge, such as Ca⁺⁺, Mg⁺⁺, Fe⁺⁺, and Fe⁺⁺⁺.  It is the combination of the sum of those cations (hardness) and the alkalinity that determines whether the water will or will not have the potential to create a chemical scale or precipitate. If the alkalinity of the water is low and the carbonate (CO3= group; actually, it would normally be present as bicarbonate, HCO3⁻)

) is not the dominant anion, i.e., negatively-charged ion in the water, the water can have a very high calcium content (be very hard) and not create a carbonate precipitate.

Alkalinity - "The acid neutralizing capacity of water is known as alkalinity. For surface waters alkalinity has been called "The Protector of the Stream", since the alkalinity of the water resists sudden changes in the pH of the stream associated with the influx of acid deposition (from the air), water containing organic acids, groundwater discharges, or industrial wastes. If you have a fish aquarium, pool, or spa, you know the importance of balancing the pH and the alkalinity of the water.

In some cases, pristine surface water and groundwater from most sandstone bedrock have very low alkalinity and therefore they would be adversely impacted by acid rain and the addition of even weak inorganic acids. The alkalinity of precipitation can be from 1 to about 10 mg CaCO3/L (which is very low). Groundwater systems from limestone bedrock or that contain interbeds of limestone or calcareous material may have an alkalinity of over 200 mg as CaCO3/L. "

The opposite of alkalinity is - Acidity!

Acidity - "The base neutralizing capacity of water is known as acidity. Acids contribute to corrosiveness and influence chemical reactions and chemical/biological processes."

Note - The pH of absolutely pure water is 7 if this water is in an atmosphere without any CO₂. When pure water is exposed to our atmosphere, which includes some CO₂, the pH of absolutely pure water is about 5.5 because the CO₂ dissolves in the water to create carbonic acid (H₂CO₃).

How Does Alkalinity Become a problem?

If the alkalinity of the drinking water is too low, it is possible that the water could be corrosive to metal piping, fixtures, and the metal components of heat exchange units and other appliances. If the alkalinity of the drinking water is too high, the water can have a salty, soda-like, or chalky taste, dry your skin, or be associated with the formation or creation of a chemical scale or precipitate which would clog piping or form a scale on filters and other heat exchange systems. If you heat water that has a very high alkalinity and the proper cations are present, you can actually watch carbonate crystals form in the water as the water gets heated. If your tea pot has a grey to white coating that can be cleaned with vinegar, you probably have water that has a high alkalinity. Therefore, the alkalinity of the water is primarily related to the potential of the water to create a nuisance.

The alkalinity of the water is an issue when attempting to treat water using water treatment processes like chlorination, iron/manganese removal, oxidation filtration, anion exchange, and Reverse Osmosis.

What are the Health Risks for Alkalinity?

Are there direct health risks associated with the alkalinity of the water? I would have to say not, but alkalinity is only one measure of the quality of the water. A water with a low alkalinity may be vulnerable to chemical corrosion of piping and fixtures that could increase the metal content of the water resulting in a condition that could create an economic nuisance such as damage to your piping, violation of a warranty on an appliance, water leaks in your home, aesthetic problems, or health problems if the level of Lead, Copper, or other Corrosion-related metals exceed a primary drinking water standard. Water with a high alkalinity may be associated with an elevated pH, nuisance issues with chemical precipitates and coatings, soap scum, a salty taste, and elevated levels of certain metals.

What are the Standards for Alkalinity?

There is not a specific drinking water standard for alkalinity, but there is a secondary drinking water standard for total dissolved solids which is relevant because a high alkalinity is associated with a high TDS. The secondary drinking water standard for TDS is set at < 500 mg/L. The general classification system for alkalinity is as follows:

Low Alkalinity - < 20 mg CaCO₃/L

Moderate Alkalinity - 20 to 160 mg CaCO₃/L

High Alkalinity - > 160 mg CaCO₃/L

Note - It is our professional experience that when the alkalinity of the water is less than 50 mg CaCO₃/L and over 180 mg CaCO₃/L, most individuals begin to experience aesthetic or use issues with the water.

Get Tested | Alkalinity

We test the alkalinity of drinking water, not because it specifically creates a health or aesthetic problem, but because it can be associated with various other types of problems and it is necessary to know the alkalinity to properly size and design many water treatment systems. When we document the alkalinity of the water, it is part of a number of parameters that may be checked when it is thought the water may be Corrosive, or its opposite, scale forming, or when you are considering the use of an Oxidation Filtration, Chlorination, or anion exchange system.

Level 1 | Observational Self-Testing

Level 1 Notes on Alkalinity

If you water has a metallic taste and occasionally appears blue and leaves blue green stains, you may have a problem associated with water with a low alkalinity, low Hardness, and low pH, i.e., corrosive water. If you have an issue with clogging pipes, a lot of scale formation, and intermittent blue-green water, you may have a problem with water that has a high alkalinity, high hardness, and an elevated pH.

Observations for Alkalinity

You may experience problems with your water if the alkalinity is too low or too high.  If the alkalinity is too low, you may experience corrosion-related problems with the water.  If the alkalinity is too high, you may experience problems with washing clothes, formation of chemical scales, or clogging of water piping and related equipment.

Try Our Level 1 Drinking Water Self-Diagnostic Tool
Have water issues? Answer our self-diagnosis questionnaire from your observations to get an initial diagnosis. Then follow our recommended steps to remediate your issue.
Self-Diagnostic Tool

Level 2 | Do-It-Yourself Water Testing

Level 2 Testing is Do-It-Yourself testing that can be done in your own home using a Testing Kit. After you’ve done Level 1 Testing, Level 2 Testing can confirm if your observations are correct. If your test results reveal the presence of a contaminant that is cause for concern, you can either proceed to determine the best treatment (see below) or continue to Level 3 Testing.

Notes on Level 2 Testing for Alkalinity

There are a number of low-cost dip tests and in-home screen tests that measure the alkalinity of your drinking water.

Recommended Level 2 Tests
Water Check Deluxe

<div class="product-note in-L4-carbon-filtration">Note: For rural Areas with <a href="/indoor-6/herbicides-pesticides">Herbicides and Pesticides</a> Usage</div>

ST-CRYS-D-02
Crystal Quest
Countertop Water Filter With Three Cartridges

<div class="product-note in-L6-bromate">Note: If the concentration is < 0.01 mg/L</div>
<div class="product-note in-L4-methyl-tertiary">Note: Concentrations < 40 ppb</div>

ST-FILT-B-01
Filter Water
Brondell Cypress Countertop Water Filtration System (Code A27AC)

<div class="product-note in-L6-mtbe-methyl-tert-butyl-ether">Note: If the concentration is < 0.07 mg/L (POU Device)</div>
<div class="product-note in-L6-tetrachloroethylene">Note: If the concentration is < 0.005 mg/L (POU Device)</div>
<div class="product-note in-L6-trichloroethylene">Note: If the concentration is < 0.004 mg/L (POU Device)</div>
<div class="product-note in-L6-toluene">Note: If the concentration is less than 0.8 mg/L</div>

LT-CRYS-W-03
Crystal Quest
Water Softeners & Salt Free Water Conditioners

<div class="product-note in-L6-alkalinity">Note: For High Hardness / Alkalinity</div>

LT-CRYS-A-02
Crystal Quest
Acid-Neutralizing Whole-House Filter

<div class="product-note in-L6-alkalinity">Note: For Low Hardness / Alkalinity/ Low pH</div>

Recommended Products
National Testing LabsL3-NATE-W-2 | WaterCheck Deluxe

<div class="product-note in-L4-carbon-filtration">Note: For rural Areas with <a href="/indoor-6/herbicides-pesticides">Herbicides and Pesticides</a> Usage</div>

View
Crystal QuestST-CRYS-D-02 | Countertop Water Filter With Three Cartridges

<div class="product-note in-L6-bromate">Note: If the concentration is < 0.01 mg/L</div>
<div class="product-note in-L4-methyl-tertiary">Note: Concentrations < 40 ppb</div>

View
Filter WaterST-FILT-B-01 | Brondell Cypress Countertop Water Filtration System

<div class="product-note in-L6-mtbe-methyl-tert-butyl-ether">Note: If the concentration is < 0.07 mg/L (POU Device)</div>
<div class="product-note in-L6-tetrachloroethylene">Note: If the concentration is < 0.005 mg/L (POU Device)</div>
<div class="product-note in-L6-trichloroethylene">Note: If the concentration is < 0.004 mg/L (POU Device)</div>
<div class="product-note in-L6-toluene">Note: If the concentration is less than 0.8 mg/L</div>

View
Crystal QuestLT-CRYS-W-03 | Water Softeners & Salt-Free Water Conditioners

<div class="product-note in-L6-alkalinity">Note: For High Hardness / Alkalinity</div>

View
Crystal QuestLT-CRYS-A-02 | Acid-Neutralizing Whole-House Filter

<div class="product-note in-L6-alkalinity">Note: For Low Hardness / Alkalinity/ Low pH</div>

View

Level 3 | Informational Water Testing

Level 3 Testing is done through an accredited Water Testing Laboratory. With Level 3 Testing, you can order a testing kit that is used to prepare your sample and submit it to the lab. By utilizing a lab, you have the assurance that a certified water expert had analyzed your water sample. If your test results reveal the presence of a contaminant that is cause for concern, you can either proceed to determine the best treatment options (see below) or continue to Level 4 Testing - Certified Testing.

Notes on Level 3 Testing for Alkalinity

If you are conducting an informational water test, you want to also include additional testing for other water quality parameters. If you suspect the water is corrosive, you will need to include pH, Total Hardness, Total Dissolved Solids, and metals testing, such as Copper and Lead. If the water has a salty taste, you may need to check the water for Sodium, Chloride, Bromide, Lithium, and other metals and if the water has a high pH you may want to check for pH, Total Hardness, Total Dissolved Solids, and metals testing, such as Aluminum.

For a basic screening test, we recommend the National Testing Labs WaterCheck Basic or Deluxe (Private Systems and Well Water) and the City Water Basic (City Water). If you suspect a Corrosion related issue, we recommend adding the National Testing Labs Corrosion Check to your order which includes a calculation of the Langelier Saturation Index (LSI).

Recommended Level 3 Tests
Water Check Deluxe

<div class="product-note in-L4-carbon-filtration">Note: For rural Areas with <a href="/indoor-6/herbicides-pesticides">Herbicides and Pesticides</a> Usage</div>

ST-CRYS-D-02
Crystal Quest
Countertop Water Filter With Three Cartridges

<div class="product-note in-L6-bromate">Note: If the concentration is < 0.01 mg/L</div>
<div class="product-note in-L4-methyl-tertiary">Note: Concentrations < 40 ppb</div>

ST-FILT-B-01
Filter Water
Brondell Cypress Countertop Water Filtration System (Code A27AC)

<div class="product-note in-L6-mtbe-methyl-tert-butyl-ether">Note: If the concentration is < 0.07 mg/L (POU Device)</div>
<div class="product-note in-L6-tetrachloroethylene">Note: If the concentration is < 0.005 mg/L (POU Device)</div>
<div class="product-note in-L6-trichloroethylene">Note: If the concentration is < 0.004 mg/L (POU Device)</div>
<div class="product-note in-L6-toluene">Note: If the concentration is less than 0.8 mg/L</div>

LT-CRYS-W-03
Crystal Quest
Water Softeners & Salt Free Water Conditioners

<div class="product-note in-L6-alkalinity">Note: For High Hardness / Alkalinity</div>

LT-CRYS-A-02
Crystal Quest
Acid-Neutralizing Whole-House Filter

<div class="product-note in-L6-alkalinity">Note: For Low Hardness / Alkalinity/ Low pH</div>

Level 4 | Certified Water Testing

A Level 4 Certified Test Test uses chain-of-custody with a water professional coming to your home to prepare the water sample and then works with an accredited laboratory in order to certify your test results. This type of testing not only gives you the highest level of assurance in the accuracy of your test results, but can also be used as a document in legal cases. For Baseline Testing, we recommend that you use Certified Testing.

Notes on Level 4 Testing for Alkalinity

If you are testing for alkalinity, it is wise to test for other contaminants that are commonly associated or related to alkalinity, such as: Hard Water, Corrosive water, or water with an elevated level of Iron, Manganese and other salts.

Get Treatment | Alkalinity

In most cases, a water treatment system is not specifically designed to treat or address the alkalinity of the water. Most water treatments systems are installed and designed because of an issue that relates to the alkalinity of the water, such as the lack of adequate alkalinity in the water to control pH or properly treat for the target contaminant, excessive levels of alkalinity that may be related to the formation of chemical scales or coatings. In some cases, the alkalinity may need to be adjusted and the design of the water treatment system changed in order to permit the efficient removal of other contaminants.

Note -  pH and alkalinity are not the same thing.

Short-Term Treatment

If the problem is related to a concern about the corrosion potential of the water, do not boil the water. You may want to flush the lines prior to use, use cold water for cooking, and use a point-of-use filter to provide a barrier against trace metals. If the alkalinity of the water is high and you are experiencing scale formation and soap scum, you may want to consider flushing your water heater, reducing the temperature of the water heater, removing aeration devices, flushing lines, and changing the type of detergent or soap being used in appliances.

Recommended Short-Term Water Treatments

<div class="product-note in-L4-carbon-filtration">Note: For rural Areas with <a href="/indoor-6/herbicides-pesticides">Herbicides and Pesticides</a> Usage</div>

ST-CRYS-D-02
Crystal Quest

<div class="product-note in-L6-bromate">Note: If the concentration is < 0.01 mg/L</div>
<div class="product-note in-L4-methyl-tertiary">Note: Concentrations < 40 ppb</div>

ST-FILT-B-01
Filter Water

<div class="product-note in-L6-mtbe-methyl-tert-butyl-ether">Note: If the concentration is < 0.07 mg/L (POU Device)</div>
<div class="product-note in-L6-tetrachloroethylene">Note: If the concentration is < 0.005 mg/L (POU Device)</div>
<div class="product-note in-L6-trichloroethylene">Note: If the concentration is < 0.004 mg/L (POU Device)</div>
<div class="product-note in-L6-toluene">Note: If the concentration is less than 0.8 mg/L</div>

LT-CRYS-W-03
Crystal Quest

<div class="product-note in-L6-alkalinity">Note: For High Hardness / Alkalinity</div>

LT-CRYS-A-02
Crystal Quest

<div class="product-note in-L6-alkalinity">Note: For Low Hardness / Alkalinity/ Low pH</div>

Contact a KnowYourH2O Recommended Professional

Submit a Request for Consultation with the KnowYourH20 Team. Contact Us

Long-Term Treatment

In the long term the specific cause of the problem must be identified and this can only be accomplished after a comprehensive water quality assessment. The first step is a solid test of your raw untreated water and, if you already have a treatment system in place, test the existing treated water. If it is determined that the water is corrosive, then it may be necessary to install a neutralizing system. If the water is scale-forming, it may be wise to install a water softener to reduce the Total Hardness, i.e., the concentration of the divalent and multivalent cations, or to inject an acid to reduce the pH of the water.

We strongly recommend hiring a professional to assist with the selection and installation of any water treatment system.

Recommended Long-Term Water Treatments

<div class="product-note in-L4-carbon-filtration">Note: For rural Areas with <a href="/indoor-6/herbicides-pesticides">Herbicides and Pesticides</a> Usage</div>

ST-CRYS-D-02
Crystal Quest

<div class="product-note in-L6-bromate">Note: If the concentration is < 0.01 mg/L</div>
<div class="product-note in-L4-methyl-tertiary">Note: Concentrations < 40 ppb</div>

ST-FILT-B-01
Filter Water

<div class="product-note in-L6-mtbe-methyl-tert-butyl-ether">Note: If the concentration is < 0.07 mg/L (POU Device)</div>
<div class="product-note in-L6-tetrachloroethylene">Note: If the concentration is < 0.005 mg/L (POU Device)</div>
<div class="product-note in-L6-trichloroethylene">Note: If the concentration is < 0.004 mg/L (POU Device)</div>
<div class="product-note in-L6-toluene">Note: If the concentration is less than 0.8 mg/L</div>

LT-CRYS-W-03
Crystal Quest

<div class="product-note in-L6-alkalinity">Note: For High Hardness / Alkalinity</div>

LT-CRYS-A-02
Crystal Quest

<div class="product-note in-L6-alkalinity">Note: For Low Hardness / Alkalinity/ Low pH</div>

Contact a KnowYourH2O Recommended Professional

Recommendation: Seek Advice from a Local Professional (Customized Solution). Contact Us

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