Harwich Water Department Water Quality
Water Quality Testing Program
Does the Harwich Water Department test my drinking water?
Yes. The Harwich Water Department regularly tests for all contaminants required
under the Safe Drinking Water Act. The test frequency varies, depending on
the contaminant. Contaminants which are more likely to be found in drinking
water and that may have acute health effects are tested the most frequently.
For example, the Harwich Water Department collects 30 samples for coliform
bacteria each month, while more unusual contaminants, such as pesticides,
are tested once every three years. If the level of a contaminant is above
the health standard, then the Department must notify the public and corrective
action must be taken immediately.
What are the current drinking water standards?
Under the Safe Drinking Water Act passed in 1974, the U.S. Environmental Protection
Agency (EPA) established drinking water standards regulating over 100 different
contaminants. These standards are divided into two categories: primary standards
and secondary standards. Primary standards limit the levels of contaminants
that may endanger public health, and they are legally enforceable. Secondary
standards are non-enforceable guidelines for contaminants that affect the
aesthetic appearance of drinking water. These contaminants have no known
adverse health effects at the concentrations typically found in drinking
water, and are tested for because they may affect the taste or smell of drinking
water.
The Town of Harwich has ground water VOC cleanup standards that
are more stringent than the EPA's. The concentration of any single
VOC can not be greater than one part per billion, or if a combination
of VOCs are present, five parts per billion.
How are the standards set?
The EPA has determined a maximum contaminant level (MCL) for all regulated
contaminants. MCLs are enforceable standards, based primarily on protecting
public health in the most stringent manner possible. Prior to setting MCLs,
the EPA sets maximum contaminant level goals (MCLGs), which equal the concentration
of a contaminant that may be safely consumed over a lifetime with no adverse
health effects. For all carcinogens (substances which cause cancer), the
MCLG is set at zero. The MCL is then derived by taking the number closest
to the MCLG that is technically and economically feasible. Ultimately, the
MCL should equal the MCLG for each contaminant. For many contaminants, such
as fluoride, this is already true.
What types of contaminants are included under the primary standards?
The contaminants under the primary standards are divided into four groups:
- Inorganic chemicals
- Organic chemicals
- Radionuclides
- Microorganisms
What are the health effects of these contaminants? Where do they
come from?
Inorganic chemicals mainly consist of toxic metals, such as lead,
copper or mercury, as well as many others. The effects of these
substances are varied. Some inorganic chemicals such as fluoride
and arsenic naturally occur in water in certain areas, while lead
and copper might come primarily from pipes or human activity.
Organic chemicals (substances containing carbon) include trihalomethanes,
pesticides and volatile organic chemicals (VOCs). These contaminants
may cause liver, kidney and spleen damage, anemia, central nervous
system problems and cancer. VOCs may also cause reproductive disorders
and birth defects. The source of these chemicals varies. Trihalomethanes
are formed if the chlorine added to drinking water reacts with
natural organic matter in the water. Pesticides may come from runoff
or leaching from insecticide or herbicide use. VOCs, which include
paint thinners, varnishes and fuel additives, may come from discharge
from factories or leaching from landfills.
Some common radionuclides are radon, radium and uranium, which
all may increase the risk of cancer. Naturally occurring radionuclides,
as well as man-made radionuclides, may be absorbed into water from
the soil and bedrock.
Microorganisms include bacteria, viruses and parasites. The most
common effects of these microorganisms are cramps and diarrhea.
These contaminants come from human and animal fecal waste.
Nitrate, an inorganic chemical, can have serious health effects
in young infants. High levels of nitrate can cause "blue baby syndrome" (methemoglobinemia),
which can be life threatening without immediate medical treatment.
Nitrate is a major component in fertilizer, and comes primarily
from runoff from the land surface.
What are some of the contaminants included under the secondary
standards? Why don't they have MCLs?
These include chemicals such as chloride, iron, sulfate and many others. These
chemicals may cause drinking water to have an unpleasant taste or odor, or
to have an unattractive appearance, but they pose no known health risks at
the concentrations normally found in drinking water.
What is being done to ensure that my drinking water is free of
these contaminants?
All of the Harwich Water Department sources are treated in order to minimize
the concentration of impurities. For example, nine of Acton's well sites are
aerated to prevent any VOCs from entering the drinking water. Although many
of these wells do not have a history of VOC contamination, this was seen as
a proactive way to provide maximum public health protection. In addition, a
small amount of fluoride is added to promote dental health, and the pH of the
water from all wells is adjusted to minimize leaching of pipe materials, such
as lead and copper, into drinking water.
On going, regular testing of the Department water helps detect
any water quality problems early on. Modern technology makes it
easier to reliably detect contaminants at very low concentrations.
The Harwich Water Department uses certified drinking water laboratories
that follow state-of-the-art analytical techniques. A detection
of any contaminant would result in follow up, including re-testing
and treatment, or other actions to eliminate any health concern.
This will ensure that Harwich water is of the highest quality possible.
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