Monday, October 21, 2013

Test and Think Before Treating Well Water

When I first bought my home here in the Rural Crescent of Prince William County several people tried to sell me water treatment systems, from the carpeting contractor who wanted to also sell me a whole house filter to the water softening system salesman offering “free water testing.” The free testing offered by these companies usually only tests for hardness and other contaminants that they sell treatment systems for, but there has recently come on the market home testing kits that are quite good and can test wells for health related impurities. However, because I had fully tested the well water for every primary and secondary drinking water contaminant before purchase and liked the taste of my water, I knew that water treatment was not necessary.

Private drinking water wells should be tested annually for bacteria and every 1-3 years for other common regional groundwater contaminants especially if you install treatment systems. Groundwater is dynamic and can change over time, and it is important to make sure that any treatment is still appropriate and effective. Though I know that there is a tendency to not test water because you worry about what you might find, you need to monitory your water quality. Water treatment systems are not an install and forget piece of equipment, they are systems that need to be maintained and adjusted to keep the water within ideal parameters. Improperly treated water can be as problematic as not treating water.

The Virginia Cooperative Extension (VCE) Offices in Virginia occasionally holds drinking water clinics for well, spring and cistern owners as part of the Virginia Household Water Quality Program. The VCE subsidizes the analysis cost for these clinics and Prince William Extension is planning on holding its next clinic on March 31, 2014. Currently, samples are analyzed for: iron, manganese, nitrate, lead, arsenic, fluoride, sulfate, pH, total dissolved solids, hardness, sodium, copper, total coliform bacteria and E. Coli bacteria at a cost of $49 to the well owner. This is far from an exhaustive list of potential contaminants, but with one or two exceptions these are the most common contaminants that effect drinking water wells in Virginia. These are mostly the naturally occurring contaminants and common sources of contamination: a poorly sealed well or a nearby leaking septic system, or indications of plumbing system corrosion from slightly acidic water.

There are other contaminants that can be found in ground water in certain regions that can cause illness when exposed to small amounts over long periods of time Uranium is an example. There are also nuisance contaminants for which there is not an approved EPA methodology, iron bacteria is an example. The Virginia Household Water Quality Program has been sponsoring water clinics and collecting well data in Virginia for years. They have used their database to expand their knowledge of regional water quality problems and natural contaminants. Water analysis should be performed before any treatment is considered to make sure the selected treatment is necessary and appropriate. Remember a treatment system not only has to be maintained, but curing one problem may cause another.

I have tested my well at different times of year and sometimes my water is harder than others, but also there are times when my sulfate levels have been higher than others. According to the water clinic statistics, Prince William County has very high naturally occurring levels of sulfate and elevated levels are not uncommon. The EPA guidance for sulfate is 250 ppm for taste, but may be unnoticeable at higher levels, but truly excessive levels can have a laxative effect. Hydrogen Sulfide gas (H2S) gives water that awful “rotten egg” taste and smell and can render water undrinkable because of the taste and smell. Unless you have hydrogen sulfide, sulfate concentrations can be ignored at levels up to (and possibly beyond) twice the EPA secondary limit.

Hydrogen sulfide can never be ignored and is probably the reason some wells are considered to have bad water. Hydrogen sulfide can end up in your tap water by four different routes: (1) It can occur naturally in groundwater in oil rich shale and coal seams. (2) It can be produced within the well or plumbing systems by sulfur reducing bacteria. (3) Hydrogen sulfide can form in hot water heater by either supplying a pleasant environment for the sulfate reducing bacteria or by the reaction of magnesium rod intended to prevent corrosion of the heating tank with the sulfate in the water. (4) Hydrogen sulfide gas can be caused by contamination of the well with septic waste. Systematic testing can identify the cause and cure.

Hydrogen sulfide created by sulfur reducing bacteria “eating” the sulfate can be appear over time after installing a water treatment system. According to the EPA, sulfur-reducing bacteria pose no known health risks, but can make the water and entire home smell of rotten eggs. Sulfur-reducing bacteria live in oxygen-deficient environments such as deep wells, plumbing systems, water softeners, and water heaters. Often these bacteria flourish in plumbing and water softening systems. Sulfate reduction can occur over a wide range of pH, pressure, temperature, and salinity conditions and produce the rotten egg smell and the blackening of water and sediment by the formation of iron sulfide if iron is also present in the groundwater or plumbing system. If you do not have a hydrogen sulfide problem, but do have elevated levels of sulfide, think very carefully before you install any treatment system where the sulfur reducing bacteria or iron reducing bacteria might thrive.

Low pH water or acidic water is fairly common in the Tidewater portion of the county east of the Fall Line. The pH of water is a measure of the acidity or alkalinity. The pH is a logarithmic scale from 0 – 14 with 1 being very acidic and 14 very alkaline. Drinking water should be between 6.5 and 7.5. For reference and to put this into perspective, coffee has a pH of around 5 and salt water has a pH of around 9. Corrosive water, sometimes also called aggressive water is typically water with a low pH. (Alkaline water can also be corrosive.)

Over time low pH water can corrode metal plumbing fixtures causing lead and copper to leach into the water and causing pitting and leaks in the plumbing system. The blue/green staining on plumbing fixtures observed in some older homes is caused by the slow corrison of the old copper pipes. These homes which are now quite old (copper piping has not been used for decades) typically experience occasional plumbing leaks. The presence of lead or copper in water is most commonly leaching from the plumbing system rather than the groundwater.

Though acidic water is easily treated using an acid neutralizing filter, by now it is probably too late to save your pipes from damage. Neutralizing filters use a granular marble, calcium carbonate or lime. If the water is very acidic a mixing tank using soda ash, sodium carbonate or sodium hydroxide can be used, but this can be overkill in many homes. The acid neutralizing filters will increase the hardness of the water because of the addition of calcium carbonate creating a new set of problems to address. The sodium based systems will increase the salt content in the water. Water softening systems are used to address hard water are basically an ion exchange systems that can add even more sodium to the water and may shorten the life of your septic drain field.

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