Safety & Your Water

A molecule of water, H2O, in its purest form is made up to two atoms of hydrogen and one atom of oxygen. However, that is not how water is found in nature. Every source of water, groundwater and surface water, contains different constituents. Many of these constituents are necessary for health, but some should be removed before the water is used for household purposes. Our local groundwater is no different.

When your water comes out of the tap, it has already been tested and disinfected, and is ready for consumption. We are required to make sure that the water we serve is safe, or by law we are not permitted to provide it to our customers. Community Water Company complies with standards established by the United States Environmental Protection Agency (EPA) and enforced by the Arizona Department of Environmental Quality (ADEQ), the primary regulator of drinking water quality in Arizona. With the passage of the Safe Drinking Water Act in 1974, the EPA established mandatory and voluntary drinking water standards and listed primary and secondary maximum contaminant levels for drinking water constituents. Testing requirements and regulations continue to be updated by the EPA.

Water Quality in Our Area

Local groundwater has a fairly high Total Dissolved Solids (TDS) content. TDS represents the concentration of dissolved minerals and is measured by the amounts of calcium, magnesium, bicarbonate, sodium and sulfate in the water.

Like many sources of groundwater, our water contains calcium, magnesium, bicarbonate, sodium, and sulfate. Calcium and magnesium contribute to water's "hardness." Bicarbonate refers to the alkalinity of the water. Alkalinity helps to prevent rapid pH changes. Sodium is a very soluble, natural ingredient of water. Sulfate, like bicarbonate, is a constituent of water directly correlated to hardness and can occur naturally in groundwater or be introduced by industrial activity.

The EPA regulates the quality of drinking water using mandatory and voluntary drinking water standards. Several of the constituents noted above are included in these standards. The federal government, under the Safe Drinking Water Act, established primary (enforceable) and secondary (non-enforceable) Maximum Contaminant Levels (MCLs) for drinking water. Primary MCLs regulate the concentration of numerous naturally occurring and synthetic, organic, and inorganic contaminants in drinking water. Secondary MCLs are suggested guidelines which are related to aesthetic (taste and smell) qualities of drinking water. Secondary MCLs rarely present health threats to consumers because the drinking water in question would become unpalatable well before the constituents could possibly reach harmful levels.

Discussed below is a summary of some physical characteristics and associated health issues related to TDS.

Hardness is essentially the amount of calcium and magnesium carbonates dissolved in water. Although increased hardness may cause additional scaling of plumbing, heating vessels, and spotting of dishware, there is a large body of scientific information, such as the National Academy of Sciences, Safe Drinking Water Committee's 1977 report entitled Drinking Water and Health, which demonstrates a beneficial relationship between high levels of hardness (calcium and magnesium carbonates) and the development of stronger bone structure, as well as the prevention of some cardiovascular disorders including hardening of the arteries. The hardness in our groundwater ranges from 8.0 to 28.5 grains per gallon, or from approximately 137 to 487 mg/L.

Bicarbonate is the ion normally responsible for alkalinity, or the capacity of water to neutralize acids or resist changes in pH. Bicarbonate is a natural corrosion inhibitor in soft water systems. No correlation has been shown between increased alkalinity (bicarbonate) and poor health. Evaluation of alkalinity as a health based standard in drinking water is difficult because the character of alkalinity may vary due to pH, calcium, magnesium, sodium, potassium, sulfates, and total solids.

Sodium is a very soluble and natural ingredient of water. Its occurrence is widespread. Sodium toxicity leading to hypertension (high blood pressure) has been associated with intakes of salt (NaC1) greater than 30,000 milligrams/day. This would be equivalent to drinking between 113 to 208 gallons water per day at the concentrations found in our groundwater (38 to 70 mg/L).  The daily recommended maximum allowance for sodium is 2,400 mg.

Sulfate, like sodium, is a very soluble in water. The occurrence of sulfate is also widespread, especially in the arid southwest. Because of its high solubility, sulfate is difficult to remove from water and can interfere with treatment for other constituents. Sulfate normally produces a detectable taste at concentrations of 300 to 400 mg/l. Currently the U.S. EPA Secondary (suggested) Maximum Contaminant Level for sulfate is 250 mg/l, based on taste. Local sulfate levels are in the range from 58 to 456 mg/L. Elevated levels of sulfates do not cause any long-term ill effects, however, they generally produce a detectable taste and odor.

Click here for definitions, acronym of water terms.

For additional information on hard water issues please review our annual water quality report or our other articles of interest on our web site.