Drinking water quality is becoming an ever important issue both domestically and abroad. The US, which is generally ranked highest in drinking water quality globally, still has issues with water quality from time to time. In recent years well failures due to drought, arsenic from mines, natural run-off and some pesticides and perhaps most famously chromium VI (a heavy metal) pollution, which was the subject of the 2000 film “Erin Brockovich”, have amplified the importance of quality drinking water.
There are two basic types of water supply common in developed countries, private well water and public water. Public water may in fact come from a large municipal well (or multiple wells) or they may come from surface water sources like reservoirs. Even with these two distinct sources of water there are still several common water quality characteristics that are considered when tested. For public water sources the EPA tests the water quality annually, with these reports released to the public by July 1st of each year.
These test consist of several water quality parameters, i.e. pH and alkalinity as well as six individual group tests. These groups include: micro-bacterial, disinfectants, disinfectant byproduct, inorganic and organic chemical, and radionuclides (see the full list of list of water contaminants at the EPA). Each specific organism, compound, or mineral is given a MCL or maximum contaminant level that the EPA has established to be a unhealthy concentration. Micro-bacterial test include tests for organisms such as Giardia lamblia, a common organism found in fecal matter of some animals and responsible for the disease often known as “beaver fever” a disease that often effects lost hikers that drink stream water, and total coliform which can include E. coli. Disinfectants include chemicals like chlorine and chlorine dioxide which are used to disinfect the water from micro-bacterial organism. However, these chemicals and disinfectant byproducts such as chlorite and bromate can be used in over-abundance
and exceed the EPA’s MCL, thus becoming a health risk for those using the public water. Inorganic chemicals include heavy metals like chromium and the common fertilizer compound nitrate that runs off from agricultural fields. Inorganic chemicals may occur naturally in the earth or may come from industry and agricultural run-off. Organic chemicals that the EPA test for are almost all pesticides such as alachlor or industrial wastes like benzene. They end up in run-off after applied to fields or percolate through the ground and into the ground water aquifer or released. The final group include radioactive materials. This can include naturally radioactive materials that leach radiative particles or buried radioactive material that leaches through its barriers.
Each of the above groups have different acceptable levels of concentration and different methods of treatment. Most of these contaminants are treated before it reaches your household. However, for those with well water, which includes many small home owners, these contaminants are not frequently checked if ever. According to the American Groundwater Trust nearly 40 million people receive their water in the US from private wells. Most of these well are deeper, through several intermediate aquifers and are buffered from most chemicals leaching into the drinking water and are also filtered through the fine sands and silts that the water flows through. However, it is a good idea to have water tested from time to time to check for contaminants.
Another problem that faces private well owners is over use during times of drought. This nearly occurred during the recent drought in Texas as the town of Spicewood was forced to truck water in to prevent the private wells from failing. While this can sometimes occur with public wells as well they have a greater capacity to drill more wells deeper into aquifers that are not as taxed by private well owners. Another issue with well water can come in the form of sediments. Fine sediments can slip through the screen of a well and eventually pumped out into the tap.
Another consideration for both private water and public water users is pH and alkalinity. Often considered closely related they are not and have different effects on drinking water. pH measurements measure the concentration of acids or bases in the water. This sliding logarithmic scale ranges from extremely acidic 0 to extremely basic 14. The EPA sets a range of 6.5 to 8.5 as a healthy level. Meanwhile, alkalinity is an ability of water to neutralize an acid using compounds like carbonate and bicarbonate. The presence of these compounds may not drastically change the pH of the water but can prevent the pH from changing. Low pH can cause pipes to rust faster both high and low pH can have adverse effects on a person’s digestive system. High alkalinity is the cause of ‘hard-water’ which can leave scale like residue on the pipes, dishes and other surfaces.
When building a new home or buying an existing one the first thing that you need to do, regarding water, should be to check the water quality report throughout EPA, which can generally be found in the town hall, or have the well water tested by an accredited lab. This information can give you great insight into your future water quality needs. Upon learning the results you may need to invest in a filter or softener to help purify the water. Today there are a variety of filters including whole house, under sink, sink attachments and filtering water pitchers. These filters, usually a combination of a screen and carbon filter can remove sediments and many harmful chemicals. In some cases a new well or hook up to municipal water may be in order if contaminant levels are out of compliance with EPA standards. It may also be prudent to check your water periodically to ensure your supply of water remains clean.