Quality Requirement – Well Water

posted in: Ground Water, MOA, News, Water | 1

Glass of waterBefore you drink your well water, there are a few things you should consider. Water can contain lots of dissolved chemicals, especially groundwater. Moving through rocks and subsurface soil, it has a lot of opportunities to pick up and dissolve substances. Even though the ground is excellent at filtering out the particulate matter for water, such as leaves, soil, and more, dissolved chemicals can still occur in large enough concentrations to cause problems.

Underground water can get contaminated from chemicals on the surface, including pesticides and herbicides that many homeowners use on their lawns. Road salts and even bacterial contamination from septic tanks can be cause for concern.

Groundwater often contains minerals (calcium, magnesium, iron, ect.), and other organic/inorganic substances that can affect its taste quality. If the concentration is high enough, it may be necessary to install a treatment system in order to make the water suitable for household use. (Common treatment systems include water softeners, green-sand filters, and cartridge filtration systems.) Most of the “contaminants” typically encountered in groundwater can be removed with these treatment systems; however, some contaminants, if encountered at excessively high levels, can significantly impact the viability of the well.

Private Well Water quality is an important health issue for all homeowners. The type of water quality test performed for the sale of a property is based on lender requirements, or the buyers and sellers agreement. At a minimum, the MOA requires independent testing for Coliform, Arsenic, and Nitrates (CAN). These are the “Big Three” in determining safe drinking water (please see below). Outside of the MOA, it is known as Well Safe I testing. These three tests safeguard against the most commonly found health risks. Additional testing is known locally as the Personal Individual Water Analysis (PIWA), or the Well Safe III, analyze a wider range of metals and is available if preferred but should be ordered early as they take 2-3 weeks for analysis and are much more expensive.

As mentioned previously, the three major contaminants that concern the Municipality of Anchorage ( MOA) are arsenic, fecal coliform bacteria, and nitrates. For extensive testing on the water quality of a particular well, many buyers will have us pull a PIWA sample. This extensive test is not required to obtain a COSA but performed by many homebuyers.  A PIWA includes sampling for the following: Total Coliforms, Nitrate, Nitrite, Chloride, Sulfate, Fluoride, Aluminum, Arsenic, Barium, Cadmium, Calcium, Chromium, Copper, Iron, Lead, Magnesium, Manganese, Phosphorus, Potassium, Silicon, Silver, Sodium, Zinc, Conductivity, Total Dissolved Solids, Hardness (as CaCO3), Alkalinity (as CaCO3), and PH.

Arsenic:  Arsenic is a part of the earth’s crust, occurs naturally in soil and rock, and can dissolve into groundwater. When arsenic occurs in well water, the source is almost always a natural source and rarely from human activities. Long-term exposure to arsenic can cause a number of harmful effects on the human body. There is increasing evidence that people who consume drinking water with arsenic levels for many years can have various health problems, even with under 100 micrograms per liter. Studies have also linked long-term exposure to arsenic in drinking water to increased risk of cancer.

The U.S. Environmental Protection Agency (EPA) sets standards, called “Maximum Contaminant Levels” (MCLs) for contaminants in public water systems. In October 2001, EPA established a new standard of 10.0 micrograms per liter for arsenic in drinking water. The previous MCL for arsenic had been 50 micrograms per liter. The MCL is mandatory for community public water systems and is recommended for private well water. We encourage clients to test for arsenic and contact us with any questions.

Coliform Bacteria:  Total coliform (TC) bacteria are common in the environment and are generally not harmful. Fecal coliform (FC) and Escherichia coli (E. coli) bacteria are found in greater quantities. If FC or E. coli is detected along with TC in drinking water, there is strong evidence that sewage is present; therefore, a greater potential for pathogenic organisms exists. Many health symptoms can occur as a result though it is important to note that they may also be caused by a number of other factors. In addition, not all people will be affected to the same degree; young children and the elderly are usually more susceptible.

If FC or E. coli is detected in the water system, the system must be disinfected. In most cases this includes emergency chlorination.  Once the system has been disinfected and flushed, the water should be tested again for coliform bacteria.  If only TC is detected (without the presence of fecal coliform or E. coli), the source is most likely from contamination from the environment, introduced during construction or while repairs to plumbing or a water system were underway.

Nitrates:  Nitrate is a common contaminant found in many wells in Alaska. Too much nitrate in drinking water can cause serious health problems for infants under six months of age. Nitrate (NO3) is a naturally occurring chemical made of nitrogen and oxygen and is found in air, soil, water, and plants. Much of the nitrate in our environment comes from decomposition of plants and animal wastes, though humans also add nitrate to the environment in the form of fertilizers.

Natural levels of nitrate in groundwater are usually quite low (less than 1 milligram per liter [mg/L] of nitrate-nitrogen). However, where sources of nitrate such as fertilizers, animal wastes, or human sewage are concentrated near the ground surface, nitrate may seep down and contaminate the groundwater. Elevated nitrate levels in groundwater are often caused by run-off from barnyards or feedlots, excessive use of fertilizers, or septic systems.  Wells most vulnerable to nitrate contamination include shallow wells, dug wells with a casing which is not watertight, and wells with damaged, leaking casing or fittings. Nitrate contamination of a well is often regarded as a first sign of deteriorating groundwater quality.

Various treatment alternatives (reverse osmosis or anion exchange) exist.  A common practice is to add a point of use (POU) system under the kitchen or bathroom sink.  However if nitrate levels above 10 mg/l, the MOA COSA requires a high nitrate well be evaluated (multi-step process) to verify that the well itself is not contributing nitrate contamination to the aquifer.  It should be noted that nitrate levels fluctuate through the year with lower levels typically found in late summer and fall when aquifers have been recharged.

Please contact us with any questions you may have, and we will gladly conduct research and/or take water samples to provide you with the best available information regarding your water quality.

One Response

  1. Terri barrus

    Good info! Thank you!

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