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Get Informed | Corrosivity

What is Corrosivity?

Corrosivity of a water is not the measure of one specific parameter, but an attempt to evaluate the potential for the water to be corrosive to the metal piping that is part of a water distribution system. Therefore, we are not looking for a specific contaminant in many cases, but a condition. If the water is potentially corrosive, it is more likely that the water could leach trace metals from the aquifer, well pump, piping, service laterals, water mains, fixtures, and the internal components of any appliances and piping that are in direct contract with the water. Corrosion is a complex series of reactions between the water and metal surfaces and materials in which the water is stored or transported.The corrosion process is an oxidation/reduction reaction that returns refined or processed metals to their more stable oxidation states. With respect to the corrosion potential of your drinking water, the primary concerns include the potential presence of toxic metals in the water, such as lead and copper; deterioration and damage to the household plumbing, and aesthetic problems such as: stained laundry, a bitter taste, and greenish-blue stains around basins and drains.

Corrosion will occur anywhere a galvanic cell or field can be or has been established. To do this all that is needed is two dissimilar metals that are connected directly or indirectly by an electrolyte such as water. This is the same chemical reaction that occurs within a battery. Nearly all metals will corrode to some degree. The rate and extent of the corrosion depend on the degree of dissimilarity of the metals and the physical and chemical characteristics of the media, metal, and environment.

In water that is soft, corrosion occurs because of the lack of dissolved cations, such as calcium and magnesium in the water. In scale-forming (hard) water, a precipitate or coating of calcium or magnesium carbonate forms on the inside of the piping; this is the opposite of corrosion. This coating can inhibit the corrosion of the pipe because it acts as a barrier, but it can also cause the pipe to clog. Water with high levels of sodium, chloride, or other ions will increase the conductivity of the water and promote corrosion.

Corrosion can also be accelerated by:

  • 1 ) Low pH (acidic water) and high pH (alkaline water)- For high alkalinity water - it is possible that a chemical scale may form that would help to protect against corrosion, but if a bacteria becomes established in the scale, such as SRB (sulfur reducing bacteria), you may experience a problem related to Microbiologically Induced Corrosion or MIC
  • 2) High flow rate within the piping can cause physical corrosion
  • 3) High water-temperature can increase biological rate of growth and chemical corrosion
  • 4) Oxygen and dissolved CO2 or other gasses can induce corrosion
  • 5) High dissolved solids, such as salts and sulfates, can induce chemical or bio-chemical corrosion
  • 6) If the mass ratio (CMSR) of chloride to sulfate is > 0.2, but < 0.5 there is an elevated concern, but if the CMSR is > 0.5 and the alkalinity of the water is less than 50 mg (calcium carbonate) CaCO3/L the concern should be even greater
  • 7) Corrosion-related bacteria, high standard plate counts, and electrochemical corrosion can result in pinhole leaks and isolated corrosion and aesthetic water quality problems
  • 8) The presence of suspended solids, such as sand, sediment, corrosion by-products, and rust can aid in physical corrosion damage and facilitate chemical and biochemical corrosion.


Note
-The CMSR ratio is the mass ratio or the concentration ratio of chloride to sulfate.

How Does Corrosivity Become a problem?

The primary health concern is the potential for the presence of elevated levels of lead and copper and other corrosion by-products in the water. The primary source of the lead includes the historic use of lead pipes, lead-lined tanks, and use of 50/50 lead/tin solder. Because of the concern with lead, the EPA banned the use of high-lead solders in 1986. The primary source of copper is the leaching of copper from the household piping used to convey the water throughout the home and the fixtures used in the home. Corrosion can lead to the premature failure of piping, appliances, and other water-related equipment. This would include leaks in water piping and corrosion of fixtures that may result in water damage to the home and wet conditions that may promote the growth of mold.The cost of corrosion can be expensive. Corrosion can impact you and your family's health, the aesthetic quality of your water, can waste money, and damage your household piping and fixtures. Corrosive water costs you in a number of ways:

  • 1 ) Decreases the efficiency of hot water heaters and may cause premature failure of the heater
  • 2 ) Corrodes and causes premature failure of household plumbing and plumbing fixtures
  • 3 ) Imparts a bitter taste to your water because of elevated levels of metals
  • 4 ) Results in the formation of red water or greenish-blue stains on drains
  • 5) The consumption of water with elevated levels of toxic metals, such as lead and copper have been shown to cause both acute and chronic health problems

What are the Health Risks for Corrosivity?

Besides the aesthetic concerns, the corrosion process can result in the presence of toxic metals in your drinking water. These metals include Chromium, Copper, Lead, nickel, and Zinc. The following are the recommended maximum contaminant levels for regulated public water supplies for the aforementioned metals: chromium (0.05 ppm), copper (1 ppm), lead (0.05 ppm), and zinc (5 ppm). To protect the public, the EPA and PADEP require public water supplies to be non-corrosive and the “Lead and Copper Rule” has set new action levels for lead and copper of 0.015 ppm and 1.3 ppm, respectively. Because of the toxicity of lead to children, the EPA has established a recommended maximum contaminant level of 0 ppm for lead. If a public water supply is corrosive, the state requires that the water be treated to make the water non-corrosive.

What are the Standards for Corrosivity?

There is one direct secondary standard that indicates that water should be non-corrosive and that could be interpreted to mean that the water has a Langelier Saturation Index of -0.5 to +0.5. The Langelier Saturation Index is a means of evaluating water quality data to determine if the water has a tendency to form a chemical scale. In order to use this index, the following laboratory analysis is needed: pH, conductivity, Total Dissolved Solids, Alkalinity, and Total Hardness which are used to calculate a theoretical pH. The Saturation Index =SI = pH - pHs (actual or measured pH minus the theoretical pH). The Saturation Index is typically either negative or positive and rarely 0. A Saturation Index of zero indicates that the water is “balanced” and is less likely not to cause scale formation. A negative SI suggests that the water would be under-saturated with respect to the carbonate equilibrium and the water may be more likely to have a greater corrosive potential.

Water companies, authorities, state agencies, and other experts typically use the Langelier Saturation Index as a guide along with "first-flush" testing for corrosion-related metals, pH, conductivity, and even Bacteria, such as heterotrophic bacteria and Nuisance Bacteria.

Get Tested | Corrosivity

Unlike many contaminants in drinking water, corrosion can and will impact the aesthetic quality of your drinking water before it becomes a "health" concern or causes significant damage to your household piping and appliances. Your best course of action is to get your water tested and compile as much information as possible about your water supply source, well construction, and the internal plumbing within the system. If you do have a corrosion related problem, this can be addressed through a combination of changing piping materials and fixtures and, possibly, the installation of a neutralizing system.

We recommended having the water checked for pH, conductivity, alkalinity, total hardness, heterotrophic bacteria, chlorine residual, ORP (oxidation reduction potential), lead, and copper. This is conducted by determining the lead and copper content of the water after the water has been left in the piping overnight. The first draw or first-flush sample is collected and then a second sample is collected after the line has been flushed. The first draw sample is the first one-liter of water collected from a cold water tap which has been shut off for at least six to twelve hours. After the first draw sample is collected, the system should be flushed and a second sample of the water should be collected and tested. The analysis of these samples will aid in determining if the problem is the source of the water or if the problem is localized in the distribution system. If you believe you and your family have a corrosion problem and are potentially exposed to elevated levels of corrosion by-products like lead, we strongly recommend you get a first-flush and flushed water sample for corrosion. Look for the warning signs of corrosion and speak to your physician about getting your blood checked for lead.

"Experts now use a reference level of 5 micrograms per deciliter to identify children with blood lead levels that are much higher than most children’s levels. This new level is based on the U.S. population of children ages 1-5 years who are in the highest 2.5% of children when tested for lead in their blood." (Source)

Level 1 | Observational Self-Testing

Level 1 Testing is done with simple observations that an individual can make with their own senses such as sight, smell, and taste. These observations can be readily apparent or can be observed as they change over time. In addition, accessible related information about the home can also be used to narrow down the cause of your water issues.

Observations for Corrosivity

There are a number of warning signs related to corrosion.

  • The first warning signs may be discolored water that appears bluish-green or green, green and bluish-green precipitates, or evidence of staining that appears blue or bluish-green.
  • The water may also have a bitter, acidic, or metallic taste
  • There may be signs of minor corrosion of the piping. If you are having pin-hole leaks in the piping or piping failures, this may mean you are having a severe corrosion problem.
Level 1 | Self-Test Web App
To do a quick and easy self diagnosis of your water, click the button below.
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Level 2 | Do-It-Yourself 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 Corrosivity

There are a number of low-cost screening tools to evaluate the general corrosion potential of your water, but the best includes a preliminary check for Lead, Copper, and pH of the water so there is enough data to calculate a Langelier Saturation Index. Because corrosive water can be related to bacterial issues, we suggest screening for Bacteria and in some cases Nuisance Bacteria. To evaluate the body's loading of trace metals, we recommend a hair analysis.

Recommended Level 2 Tests
National Testing LabsCityCheck Standard

<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>

View
National Testing LabsWater 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>

View
National Testing LabsWaterCheck® Standard

<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>

View
Crystal QuestCountertop 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 WaterBrondell 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>

View
Crystal QuestAcid-Neutralizing Whole-House Filter

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

View
Recommended Products
National Testing LabsL3-NATE-C-3 | CityCheck Standard

<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>

View
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
National Testing LabsL3-NATE-W-4 | WaterCheck® Standard

<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</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-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 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 Corrosivity

This type of contamination is common in city water and some well water and spring water sources. For well water users, we recommend, at a minimum, the National Testing Labs Well Water Check Standard package, but the Deluxe package is recommended if you live in an area with exposure to petrochemicals and Herbicides and Pesticides. For City Water users, we recommend the National Testing Labs Standard package.  If you suspect a corrosion problem, we suggest the National Testing Labs Corrosion Check and if you suspect a Nuisance Bacteria we suggest the iron-related bacteria test.

Recommended Level 3 Tests
National Testing LabsCityCheck Standard

<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>

View
National Testing LabsWater 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>

View
National Testing LabsWaterCheck® Standard

<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>

View
Crystal QuestCountertop 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 WaterBrondell 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>

View
Crystal QuestAcid-Neutralizing Whole-House Filter

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

View

Level 4 | Certified 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.

Level 4 | Certified Baseline Testing

If you need certified testing related to corrosion or corrosivity, it would be advisable to test for a broader range of primary and secondary drinking water parameters including trace metals and general water quality and to conduct first-flush and flush testing. If you need help with finding a certified laboratory, please Contact our team.

Get Treatment | Corrosivity

The selection or need for a treatment system depends on multiple factors that include: the water's chemical quality, the microbiological quality of the water, the composition of the household piping, and the types of water-related appliances. A water treatment system for corrosion can be designed and operated with two different objectives. If you control the source water, the system most likely would require a whole-house point-of-entry system, but if you are in an apartment or on city water, the system may only target the potential effects of corrosion, such as the removal of trace metals like lead, copper, and zinc. In these applications, a point-of-use filter is more appropriate. Periodic testing should be maintained after the treatment system is in place to ensure objectives are being met and the system is operating properly. In the case of an older home or building, i.e., prior to 2014, it may be advisable to inspect the piping in your home or system. Prior to 2014 the legal definition for "lead free" was plumbing fixtures with a lead content of less than 8 %. In 2014 the term was redefined to include only fixtures with a lead content of 0.25% and that newly installed fixtures must use the "lead free" materials, but this did not apply to fixtures currently in use.

Short Term Treatment

If a first-flush and/or flush water test shows elevated levels of corrosion by-products, we recommend that you not use hot water for any cooking or consumption and it would be advisable to flush the lines prior to use. It would be wise to have the plumbing inspected by a licensed contractor. In some cases, it is advisable to use bottled water for consumption.

Recommended Short-Term Treatments

<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>

View

<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

<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>

View

<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

<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

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

View
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Long Term Treatment

In general, there are two types of treatment systems for corrosion: a neutralizing filter or a caustic feed system. The neutralizing filter is more commonly used; it uses crushed limestone, magnesia or some other mixture and, as the water passes through the filter, the filter neutralizes the excess “acid”. Therefore, the neutralizing filter actually increases the hardness and raises the pH of the water. Neutralizing filters can be used where the raw water pH is 6.0 or greater. A limestone medium will raise the pH to only about 6.9 to 7.0. If a higher pH is needed, a magnesia filter medium should be used.

The caustic feed system offers more options and is more flexible than the neutralizing filter but requires additional safety precautions, more expertise to install, set up, and operate, and possibly more extensive testing prior to and following installation. The system can treat waters with a lower pH without adding hardness to the water. Typically, a sodium-based solution is used as the caustic source, so the sodium concentration of the water will be increased.

Therefore, households that have individuals on a low sodium diet should make the doctors aware of the treatment system and get the treated water tested. This testing should include sodium and potassium.

For water with a pH of 4.0 to 6.8 a soda ash (sodium carbonate) medium is typically used. The soda ash is usually fed into the system at a rate to produce a resultant pH of approximately 7.0. When the raw water pH is less than 4.0, a caustic soda (sodium hydroxide) solution is used.

Note - Solutions of sodium hydroxide are extremely aggressive and should only be handled by trained individuals.

In either case, it will be necessary to regularly monitor the raw water and treated water quality and it may be necessary to change or update some of the piping or fixtures in your home or system.

Recommended Long-Term Treatments

<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>

View

<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

<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>

View

<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

<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

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

View
Contact a KnowYourH2O Recommended Professional

Not Up for A DIY or You have a series of issues: Need Help Identifying a Local Know Your H20 Team Professional. Contact Us

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