Corrosive Water- VAMWON Notes From the Field

VAMWON Notes from the Field are the water/ well problems I’ve encountered as a volunteer with the Virginia Master Well Owner Network (VAMWON), an organization of trained volunteers and extension agents dedicated to promoting the proper construction, maintenance, and management of private water systems (wells, springs, and cisterns) in Virginia. The Cooperative Extension Services in Virginia manages the program and has publications and fact sheets that can help homeowners make educated decisions about their drinking water. The VAMWON volunteer or Agent can help you identify problems with the water system and provide information on suggested treatments options and other solutions. You can find your VAMWON volunteer neighbor through this link by entering your county in the search box.

I was contacted by a homeowner who had his water tested by a water company and wanted to know if his water was safe to drink without treatment. He reported the results to me as follows:
Hardness - 3 gpg
pH - 6
CO2 - 40 ppm

The tests performed did not test for bacteria, chemical contaminants, only for pH and hardness. From that information there was no way to know if the well water was in fact safe to drink. The test was free and offered by water treatment companies that were trying to sell him water treatment systems so it only performed an inexpensive test for pH, derived CO2 and hardness- characteristics they could sell water treatment systems to address.

Water hardness is usually measured by adding up the concentrations of calcium, magnesium and converting this value to an equivalent concentration of calcium carbonate (CaCO3) in milligrams per liter (mg/L) of water. However, it can also be measured in grains per gallon. Water with a hardness of 3 gpg is equivalent to 51 mg/L . This water was soft and required no treatment.

Many characteristics of water actually determine its corrosivity including pH, calcium concentration, hardness, dissolved solids content and temperature. Water that is soft and acidic tends to be more corrosive, but water corrosivity is usually measured by saturation indices. Water with a pH lower than 6.5 is commonly called corrosive or aggressive water by water treatment sales people, which simply means it is slightly acidic. While consuming corrosive or aggressive water is not in itself dangerous, consuming some of the contaminants that may be dissolved from metal plumbing by corrosive water may pose health risks, particularly metals like copper and lead. That concern is mitigated if the household plumbing is PVC rather than metal piping. Corrosive water can also shorten the life of hot water heaters, washing machines and dishwashers. The pH scale is logarithmic. This means that water that has a pH of 6.0 is 10 times more acidic than water with a pH of 7.0, nonetheless, the water with a pH of 6 is about as acidic as a latte from Starbucks. It is not necessary to treat slightly acidic water if household piping is PVC, but treatment can be done simply with an acid neutralizing filter.

It is possible to measure CO2 directly in water using a TOC carbon analyzer. The injected sample is acidified to purge all of the CO2, which is then measured on an IRGA - infrared gas analyzer-detector. It is very unlikely that the fee test offered by a water treatment company used that level of analysis. H2CO3 and dissolved CO2 are in equilibrium with each other. Typically CO2 is a derived value using the pH measured at the tap. There is no drinking water standard for dissolved CO2, typically dissolved oxygen and CO2 content are of concern for ecosystem balance in surface waters. Ground water typically has CO2 concentrations under 50 ppm and I believe the derived measurement was given because CO2 has lots of “buzz” around it.

The calcite and calcite-blend filters used to neutralize corrosive water in homes work by adding calcium to the water, and will increase the calcium carbonate, hardness, of the water, making the water 'harder'. However, most acidic well water is soft to begin with, and after passing through the neutralizing filter it will be harder, but usually not hard enough to warrant a water softener. Generally, if the water is less than 170 mg/L or 10 grains per gallon, the water does not need softening. His water was 3 grains/gallon to begin with, after the neutralizer it would be expected to be 5 to 7 grains per gallon, as neutralizers typically add 3 - 4 grains per gallon on average. His water should still be well below what is considered “hard” and should not present any significant problems. Hard water can cause spotting and lime scale buildup in appliances shortening the life of hot water heaters, dishwashers and washing machines.

Acid-neutralizing filters consist of a corrosion-resistant tank filled with calcite (calcium carbonate in the form of limestone or marble chips) or a mixture of calcite and magnesium oxide (also called corosex). Neutralizer filters cost under $1,000 for homes with 3-5 bathrooms (installation is extra). Once you install a water treatment system, it must be maintained properly. Frequent maintenance is required for neutralizing filters. The tank must be routinely refilled with neutralizing material as it is dissolved. The rate of refilling can range from weeks to months depending on the raw water corrosivity, water use, and the type of neutralizing material. Backwashing is recommended to remove trapped particles that can promote bacterial growth and oxidized metals unless a sediment filter is installed ahead of the unit then of course the sediment filter will require maintenance. Always consider carefully if you should be treating your water before you start buying and installing water treatment systems.

A drinking water well that is contaminated could significantly impact your health and the value of your property. There is no requirement to test private drinking water wells for all the primary and secondary contaminants of concern to the US EPA under the Safe Drinking Water Act. The local health departments have local rules and regulations for the installation of wells and initial testing of the water for bacteria, but as the well owner you will need to take the initiative and test your water to make sure it is safe to drink. None of the testing done so far on this well would have tested if the water was safe to drink. Though there are many potential contaminants to groundwater that can impact your health, the Virginia extension recommends at a minimum testing for: total coliform, E. Coli, sulfate, nitrate, fluoride, copper, lead, arsenic, hardness, total dissolved solids, pH, manganese, iron, sodium.

The Virginia Extension Office runs several subsidized water clinics each year. This year, 2012, we will be having a clinic in Prince William County in the early winter. Albemarle County will be having a clinic in April 2012, Loudoun and Frederick counties will have water clinics in May 2012, Page, Shenandoah and Warren counties will have water clinics in June 2012. Water analysis for the clinics is being subsidized by the Extension program and will cost only $55 trained extension agents and volunteers will be available to interpret your results.

Test Your Well Water

If your home drinking water is supplied from a private well, you are responsible for ensuring that your water is safe to drink. Unlike public drinking water systems serving many people which have experts regularly checking the water quality, no one is looking out for families with their own wells. The US EPA’s Safe Drinking Water Act does not protect private wells. You are responsible for ensuring that the water supplied from your private well is safe to drink and palatable. Managing your water is an ongoing process like managing your health.

The US EPA estimates that 10% of America obtains their drinking water from private wells. In Virginia that number is much higher, 34% of the population is estimated to obtain their drinking water from private groundwater wells. The Master Well Owner Network (MWON) is an organization of trained volunteers dedicated to promoting the proper construction, maintenance, and management of private water systems (wells, springs, and cisterns) in Maryland, Pennsylvania, Delaware, West Virginia, and Virginia. The Cooperative Extension Services in Delaware, Maryland, Pennsylvania, Virginia and West Virginia manage the program and have numerous publications and fact sheets that can help homeowners make educated decisions about their drinking water. The volunteers can help homeowners interpret their test results and make educated decisions about what treatment might be appropriate and desirable.

According to the US EPA actual events of groundwater contamination have historically been rare and typically do not occur at levels likely to pose health concerns. City and county health departments have local rules and regulations for the installation of wells. The water well test that was performed when you bought your house or installed your well probably only tested for bacteria and nitrates. Due to its protected location underground, most groundwater is naturally clean and free from pollution. However, not all groundwater is clean and safe it can become polluted.

Before initially using a water well you should completely test the water for contamination. A good start would be the list of primary and secondary contaminants that the US EPA regulates under the Safe Drinking Water Act and pesticides. This would cover total Coliform and E. Coli bacteria, heavy metals, inorganic chemicals, physical factors (like harness, pH, turbidity, etc.), trihalo methanes, volatile organic chemicals (solvents), and common pesticides, herbicides and PCB’s. These tests are not cheap, but should not be skipped. The Minimum Detection Levels, which are the lowest levels at which the laboratory detects a contaminant with an acceptable degree of accuracy should be below the levels established by the Safe Drinking Water Act.

Once the initial full test is completed annual testing of solvents and pesticides may not be necessary unless a local problem is identified or a spill occurs. Occasional testing for these substances should still be done. As development in our modern society increases, there are a growing number of activities that can contaminate our drinking water. Increased population density brings more opportunities for nutrients and chemicals from land disposal practices, septic systems, lawn fertilizers, household cleaners and pest treatments to contribute to water pollution. In reality, the nearest ongoing sources of potential contamination to your drinking water supply is your own or your neighbors septic system drain field.

However, all private water wells should be tested every year for total coliform bacteria, and E Coli, nitrates, total dissolved solids and pH levels at a minimum. Part of the price of your own water supply is maintaining it and testing it. You can not taste bacterial contamination from human and animal waste and you can not taste nitrate nitrite contamination. Since bacterial contamination cannot be detected by taste, smell, or sight, all drinking water wells should be tested at least annually for Coliform bacteria and E Coli. Due to the extra cost (under $20) most health departments only recommend total coliform testing. Total coliform counts give a general indication of the sanitary condition of a water supply and nothing more. Total coliform includes bacteria that are found in the soil, in water that has been influenced by surface water, and in human or animal waste. Fecal coliform is the group of the total coliform that is considered to be present specifically in the gut and feces of warm-blooded animals. E. coli is considered to be the species of coliform bacteria that is the best indicator of fecal pollution and the possible presence of pathogens. If a sample is positive for coliform bacteria a second test for fecal coliform and E Coli can be performed.

Contamination from human and animal waste and chemicals can be real health hazards and should be addressed immediately. However, most of the water quality issues with private wells are from naturally occurring contamination or impurities. These are contaminants or impurities that are produced from the underlying soil and rock geology. From the underlying rocks radionuclides and heavy metals can enter the groundwater. There are areas with natural occurring arsenic, cadmium, chromium, lead, selenium and fluoride. While some of the symptoms of mineral contamination are obvious, sometimes one symptom can be confused with another. Never buy a treatment system until you have tested your water fully for all heavy metals and hardness, determined if there is a problem and identified the correct solution. Other contaminants may be present that need to be addressed. While many natural contaminants such as iron, sulfate, and manganese are not considered serious health hazards, they can give drinking water an unpleasant taste, odor, or color. The MWON volunteers can help you obtain sampling, and interpret your test results. Do not rely solely on water treatment salespeople for water analysis. The tests they perform are often crude and sometimes misleading. They are selling water treatment.