Post contributed by Brent Brelje – Principal Engineer for SLR International Corporation. Brent grew up destined to be a water treatment engineer; his first job was washing test tubes in the family’s water quality lab. Brent is a civil engineer and has been designing, installing, and operating groundwater treatment systems since 1985.
One of the curious benefits due to the boom in natural gas drilling is that many homeowners are now receiving, free of charge, comprehensive analyses of their well water. For years, professionals have been urging homeowners to get basic testing done and now many homeowners find themselves overwhelmed at the amount of data they receive as part of the testing.
The questions I hear over and over again are what does all this mean, is my water safe to drink, and do I need to treat my water?
By comparing your data to the standards, you can determine if your water is considered by the state to be safe to drink for the constituents analyzed. (Be careful when comparing numbers – different units are used by different labs so make sure the units shown in your results are the same as the MCL.)
There are primary contaminants and secondary contaminants. The primary contaminants are health related and the standards for the secondary contaminants are there for aesthetic or maintenance reasons. For example if your water is high in iron it is not a health problem, but your water may have a brownish tinge or you may experience reduced life in your water heater.
So what if my well water does exceed one of the standards? What do I do?
First of all, it is not uncommon for a parameter to be detected above standards. It has been reported that somewhere between 30 and 50 percent of all private wells in Pennsylvania are thought to have at least one parameter that doesn’t meet the standards. Some of the most common culprits are bacteria, iron, manganese, and arsenic.
If your water was found to contain bacteria, the first thing you should do is inspect your well. One of the most common problems is that surface water may be entering your well. Preventing surface water from entering your well is key and you must correct any of the above problems before the water quality in your well can be improved. If your well is improperly located – within 100 feet of a stream, septic tank, or other source of bacterial contamination – you should have a new well drilled and properly abandon the improperly constructed well. If your well is very shallow (shallow casing depth), hand dug, or you receive your water through a spring you will invariably have a continuing problem with bacteria. Again you should consider installing a new well and abandoning the shallow well.
If your well is intact and located correctly, you may be able to shock chlorinate your well to kill the bacteria in your well and household piping. After chlorination you should have your well retested. If the shock chlorination did not successfully eliminate the bacteria you may need to install a permanent disinfection system. If you are handy, there are several websites that sell treatment equipment and do offer good advice http://www.cleanwaterstore.com/ and http://www.budgetwater.com/index.htm. You can also contact local water treatment contractors such as Culligan who will provide, install, and maintain the equipment.
Iron and Manganese
High levels of iron and manganese commonly occur together. Because these compounds do not present a health risk, installing treatment equipment to remove these compounds is typically done based on the owner’s preference. Staining of sinks and toilets as well as clogging of dishwashers, washing machines, and water heaters are common reasons to install treatment equipment. There are many ways to remove iron and manganese, but all methods rely to some extent on oxidation and filtration.
High arsenic occurs in about 10 percent of private wells in Pennsylvania. Arsenic is a health concern and should be addressed. It may make sense to talk to your local well driller to see if there is a possibility of drilling a shallower well to avoid the arsenic – in some areas it is known that there is high arsenic at certain depths in the groundwater. If your arsenic concentration is below 100 parts per billion, there are filters that will reliably remove the arsenic to below the MCL. For higher levels of arsenic, distillation may be the only reliable method to provide a safe drinking water source.
Copper and Lead
Elevated levels of these compounds may be associated with plumbing in your house. High levels of lead may arise from brass components in your piping or from older copper plumbing that used solder with high lead concentrations. High copper is often found when the water has low pH or is otherwise corrosive and is actually dissolving the copper piping. If you have copper piping and have high concentrations of lead or copper, the first step is to sample your well as close to the wellhead as possible, eliminating as much contact as possible with copper piping. If the lead and copper values are lower, it is likely that your household piping is causing the problem and needs to be addressed. High levels of lead and copper in well water are relatively rare and can be treated with a point of use drinking water system using reverse osmosis or distillation.
Methane is commonly found at relatively low levels in all groundwater and has been found to be naturally occurring at relatively high concentrations in Pennsylvania. Methane is not toxic; there is no adverse health effects in drinking water with methane dissolved in it.
Typically concentrations less than 7 parts per million (ppm) are not a great concern, but if the concentrations are near 7 ppm, a vent should be installed on your well to release any accumulated gas that could be in your well. Determining when the methane concentration is a flammability concern is difficult. It depends on how much water is used, how much volatilization there is when the water is used, how does the methane dissipate in the house, and the temperature of the water. At concentrations above 7 ppm additional sampling for methane should be performed. Methane monitors could also be installed in your home and can help you determine if there is a problem. A conservative approach is to consider some form of methane reduction when the methane concentration approaches 10 ppm.
Methane is easily removed by aeration; however aerating well water often causes iron and manganese to precipitate. In addition, if the methane is not completely removed, the added oxygen can stimulate bacterial growth in your plumbing system. So if your methane concentration is high and you are aerating the water to remove methane, make sure your system includes filtration and some form of disinfection. Disinfection using chlorine should not be used because it is likely that the chlorine will combine with trace amounts of methane remaining in the water creating trichloromethane which has its own MCL.
Sulfur odors commonly occur where there is some methane or other organic present in the groundwater. This can also be treated by aeration, just like methane. In some cases when the odor is not severe, it can be treated by simply using an older style air storage tank rather than the more common bladder tank. This may cause more bubbles and air to be suspended in your water – which some people find objectionable – but it is a relatively inexpensive solution when the odors are relatively mild. A carbon filter is also effective in removing sulfur odors from water.