I have received some questions lately about water well testing, such as How to test, where to send the sample, what to test for and what do the results mean? The Soil, Water and Forage Testing Laboratory through Texas A&M AgriLife Extension Service will only test water for livestock or irrigation purposes. They do no test water for human consumption. Locally, water wells used for human drinking water can be tested through the Wichita Falls Health Department.
Water testing is performed Monday through Thursday; samples must be received prior to 3 p.m. The laboratory provides free sterile and buffered collection bottles. These are the only containers in which samples will be accepted. The fee for Total Coliform and Private Water Well Samples is $15 per sample. More information can be found on their website at http://www.WichitaFallstx.gov.
Private wells do not serve public water systems and are therefore largely unregulated. For domestic water well owners there are no federal or state requirements for monitoring drinking water quality as these are for public water supply systems. Likewise, there are no “right to know” reports informing well owners of the quality of their drinking water and no requirements for treatment.
The U.S. Environmental Protection Agency (EPA) has set two categories of standards for public drinking water – primary standards and secondary standards. Primary standards are set for contaminants that when consumed can harm human health. Secondary standards regulate contaminants that are a nuisance but do not harm human health, such as those that cause offensive taste, odor, corrosion, foaming or staining. While these standards are for public water supplies, we can use them to compare our private water well tests.
The most common problem associated with ground water may by hardness, generally associated with an abundance of calcium and/or magnesium dissolved in the water. Hard water has not been shown to cause health problems but can be a nuisance as it may cause soap curds and deposits to form on pipes and other plumbing fixtures. Over time, this can reduce the diameter of pipes. People with heart or circulatory problems may want to consult their physician before drinking softened water, because the softening process removes calcium and magnesium and adds sodium to the water. There is no EPA drinking water standards set for calcium or magnesium; they are included in TDS.
A “rusty” or metallic taste in water is a result of iron, and sometimes manganese, in ground water. They may not only create a bad taste, but they also can stain pipes and clothing. Iron and manganese are naturally occurring, and most ground water has some amount of dissolved iron and manganese in it. The secondary standard for iron is 0.3 ppm.
Most nitrogen in ground water comes from the atmosphere. Some plants can “attach” nitrogen from the atmosphere onto their roots. The nitrogen not used by plants is then released into the soil. Nitrogen compounds also can work their way into ground water through fertilizers, manure and urine from farm animals, sewage and landfills. The most common forms in groundwater are ammonia, nitrate and nitrite. Nitrates can be especially toxic to children under six months of age.
Sulfur can occur in groundwater in two forms: sulfides and sulfates. Sulfates often come from the dissolving of minerals, such as gypsum and anhydrite. A “rotten egg” smell coming from your water indicates the presence of hydrogen sulfide gas. Along with creating an unpleasant odor and taste, sulfides cause corrosion to plumbing and darkened water. Sulfur in an amount greater than 250 ppm can cause diarrhea.
Total dissolved solids are the concentration of all dissolved minerals in water. It is the direct measurement of the interaction between minerals and ground water. TDS levels above 1,000 mg/L will usually yield poor tasting water. Levels above 2,000 mg/L are considered undrinkable due to taste, and levels more than 10,000 mg/L are defined as undrinkable. The EPA secondary drinking water standard is 500 ppm.
Sodium is dissolved from rock, salts and soil. It is also found in oil-field brine, sea water, industrial brine and reclaimed effluent water, etc. Moderate amounts of sodium have little effect on the usefulness of water; however, persons on low sodium diets should consult their physician for levels above 20 ppm. The Secondary Water Standard is also 20 ppm.
Other water analysis parameters include pH and Conductivity. Water with high acidity may dissolve iron from pumping facilities and mains and produce a “red water” problem. The EPA secondary drinking water standards for pH are 6.5 to 8.5. Conductivity is an indicator of salinity. High conductivity is an indication of TDS. This value should only be used as an initial screening parameter. Other individual characteristics should be evaluated when conductivity levels are high. A current limit is not established for domestic water. Concern over soil salinity is greatest when irrigating with water high in salts, where soils are poorly drained and allow for excessive surface evaporation, or where soils are naturally high in salts due to limited leaching and shallow water tables. As soluble salt levels increase, plant utilization of soil water often declines.
For a complete list of water quality parameters or for more information about water testing, contact the A&M AgriLife Extension office of Clay County at (940) 538-5042.