To comply with the required regulations, MVD tests for various contaminants, including inorganic contaminants (salts, metals), organic chemical contaminants (synthetic and volatile chemicals), and radioactive contaminants as well as some additional unregulated contaminants/chemicals. Water analyses and treatments are performed as required and directed by the EPA’s Safe Drinking Water Act (SDWA) and the NHDES Drinking Water and Groundwater Bureau (DWGB). All water tests are performed by an independent laboratory that is accredited in accordance with the National Environmental Laboratory Accreditation Program (NELAP) & the New Hampshire Environmental Laboratory Accreditation Program (NHELAP). All testing is reported to and monitored by the NHDES. Results from these tests are provided on MVD’s Annual CCR (Water Quality Report).
Below is information regarding the most common concerns/questions from MVD’s water customers.
APPEARANCE
Cloudy/”Milky”
Cloudy or “milky” water is caused by air which is harmless. As the water sits, the air will dissipate and the water will clear. The most frequent reasons of air in the water mains and/or service lines are from the following:
Outages
Pressure Fluctuations
High Usage (ex. water main flushing or excessive seasonal usage)
Water Main/Service Line Breaks
Plumbing Disturbances (ex. repairs damage/leaks)
Temperature – cold water holds more air than warm water.
Brown/Orange
Brown or orange colored water is typically from sediment, such as naturally occurring iron, that accumulates in the water mains located in the street and in the service lines connected to the water. While discolored “brown” water is not aesthetically pleasing it is not unsafe*. Sediment is normally settled in the mains and service lines, however it can be “stirred up” causing it to dislodge and subsequently discolor the water. The most frequent reasons for the water to be “stirred up” are from the following:
Outages
Pressure Fluctuations
Repairs/Construction
High Usage (ex. water main flushing or excessive seasonal usage)
Water Main/Service Line Breaks
Plumbing Disturbances (ex. repairs damage/leaks)
Discolored water can be easily resolved by flushing the water service line to the property. Flushing allows a larger than normal quantity of water to flow through the service line which helps clear out the sediment. Note: the discoloration can return after the water has sat in the lines for a period of time, such as overnight or during the day if it’s not being used – this is to be expected. When the water is not used for a longer period of time the sediment settles, when water is turned on it is agitated and the discoloration returns. If this happens you may repeat the flushing process. If your water is discolored, we recommend avoiding the use of hot water until the cold water is clear. If you are noticing discoloration in the hot water, the water heater may need to be flushed – refer to the manufacturer’s manual for additional information or contact a licensed plumber.
“Sandy”
What appears as “sand” is actually a derivative of calcium carbonate, a naturally occurring compound. Sand” happens when your hot water heater temperatures are set too high – refer to the manufacturer’s manual for additional information or contact a licensed plumber.
TASTE/SMELL
Chlorine/Bleach
Chlorine is a highly efficient disinfectant. MVD uses chlorine to neutralize bacteria, parasites, viruses, and assorted harmful microorganisms before it enters the distribution system and is used by customers. The EPA mandates that a certain level of chlorine be present in public water supplies which is known as a “residual.” The maximum residual is 4 mg/l. MVD’s levels are typically lower that 1 mg/l which is well below the maximum and therefore the presence of chlorine is typically unnoticed. The strength of chlorine scent/taste can depend on the distance of your property to the treatment source (the further away the property is, the more the chlorine dissipates) as well as the time of year. For example, chlorine dissipates more quickly in warm weather so treatment levels may be increased in order to compensate for the dissipation. Additionally, the strength of the taste/smell is different for each person – some people are more sensitive to chlorinated water than others. While a chlorine smell is certainly unpleasant, over time, chlorinated water will naturally lose its smell, but if preferred using a filtration system will eliminate the odor immediately.
Sulfur/”Rotten Eggs”
Sulfur bacteria are naturally present in groundwater. The smell of sulfur is produced when sulfur bacteria break down organic matter and release hydrogen sulfide gas, often leaving an aroma of rotten eggs. Sulfur bacteria dwell in oxygen deficient environments such as plumbing systems and feed on decaying organic matter, creating hydrogen sulfide gas that gets trapped in water sources. If you smell sulfur only when you use the hot tap, your water heater may be the culprit. Reactions caused by the magnesium rod and aluminum in your water heater produce hydrogen sulfide gas, yielding a stronger sulfur scent when you use the hot water – refer to the manufacturer’s manual for additional information or contact a licensed plumber.
*Some people may be more vulnerable to contaminants in drinking water than the general population. These people should seek advice about from their health care providers.
