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2013 Water Quality Report
Cohasset Water Department, 339 King Street, Cohasset, MA 02025 (781) 383-0057 http:/www.cohassetwater.org
WATER QUALITY REPORT
The Cohasset Water Department (DEP ID# 4065000), under
the direction of the elected Board of Water Commissioners,
provides public drinking water to about 2,600 connections for about
7,000 Cohasset residents and provides and maintains a water system
for firefighting. We provide drinking water for almost 90% of the
population of Cohasset.
This Water Quality Report describes the sources of your
drinking water and the quality of that water for the period from
January 1 - Dec. 31, 2013. We are pleased to report that during the
past year, the water quality delivered to your home or business
complied with all state and federal drinking water requirements.
WHERE THE WATER COMES FROM
The Cohasset Water Department drinking water comes from
two surface water supplies, Lily Pond (DEP ID# 4065000 -02S), and
the Aaron River Reservoir (DEP ID# 4065000-01S). Lily Pond has a
maximum capacity of about 100 million gallons of water and is 52
acres in size. The 136 acre Aaron River Reservoir, which can hold a
maximum of 550 million gallons of water, is used to supplement Lily
Pond in times of high water demand.
The watershed for Lily Pond and the Reservoir covers an area
of 5,892 acres, 9.21 square miles. O nly 2,339 acres (or 40%) is in
Cohasset. The safe yield of our surface water supplies is 5.2 million
gallons per day (gpd). Our average daily demand in 2013 was about
734,000 gallons per day, and the maximum daily demand was about
1.6 million gallons.
The Water Department has one ground water source - the
Ellms Meadow Well field (ID# 4065000 -02G), located at 16 James
Ln., which has been approved for up to 170,000 gallons per day.
The distribution system of Cohasset is connected to both the
Hingham water system and the Scituate water system. In the event
of a water emergency, these interconnections could be opened to
transfer water from one system to another.
Great News!! Lead Residuals Below Action
Levels Again
The Cohasset Water Department performed its
required sampling for Lead and Copper between July and
September 2013. This process consisted of taking
samples from 20 different residential homes and two
different schools located in Cohasset.
The sampling plan was approved by the DEP based
on when the home was constructed and the type of
material used in the service line to the home. The
sampling plan is intended to capture locations with the
highest potential for lead exposure in drinking water.
The results of these tests show that 95% of the
samples collected were below the Action Level for Lead.
This is great news and reinforces our ongoing
commitment to providing high quality water.
We are proud of our success, but encourage all
customers to continue using measures to reduce the
potential for lead exposure:
Always flush the cold water line for 20-30 seconds
before drawing water for drinking and cooking purposes.
CONSERVATION NOTE: Use this flushed water to
water your plants or for cleaning!
For more information, consult our Lead
Education Brochures which are available at the
Water Department offices, town library, and on our
website-www.cohassetwater.org
Vulnerable Populations Warning
Some people may be more vulnerable to contaminants in
drinking water than the general population. Immuno-
compromised persons such as persons with cancer
undergoing chemotherapy, persons who have undergone
organ transplants, people with HIV/AIDS or other immune
system disorders, some elderly, and infants can be
particularly at risk from infections. These people should seek
advice about drinking water from their health care providers.
EPA/CDC guidelines on appropriate means to lessen the risk
of infection by Cryptosporidium and other microbial
contaminants are available from the Safe Drinking Water
Hotline (1-800-426-4791)
Community Involvement
We encourage public interest and participation in
Cohasset's decisions affecting drinking water.
The Water Commission meets regularly at the Lily
Pond Water Treatment Plant, 339 King Street.
Please attend and participate in our meetings.
Meeting notices are posted at Town Hall and on our
website.
Please call Brenda Douglas at the Water
Department at 781-383-0057 (fax 781-383-2906) with any
questions or concerns.
The Water Department generates an annual Water Quality
Report. This report is available at the Water Department,
Town Hall, the Paul Pratt Memorial Library, and on our
website, www.cohassetwater.org.
Cohasset Board of Water Commissioners
Peter DeCaprio- Chair
Leonora Jenkins – Clerk
Daniel Varney
page 2
SOURCE WATER ASSESSMENT PROGRAM
(SWAP)
The Massachusetts Department of Environmental
Protection (MassDEP) prepared source water assessments
in 2004 for all public water systems as required by the Safe
Drinking Water Act amendments. A susceptibility ranking of
high was assigned to this system using information collected
by the DEP.
The Cohasset Water Department, SWAP can be found
online at http://www.mass.gov/dep/water/drinking/3065000.pdf
We encourage our customers to become familiar with this
report. The report identifies steps you can take to help protect
our sources of drinking water here in Cohasset. Note: The
Route 3A transportation corridor presents a moderate hazard
to our drinking water supply, as a result of potential vehicle
accidents or chemical spills. To alleviate this hazard, an
oil/water separator has been installed in the Pond St area and
rain gardens have been installed throughout much of the
watershed.
HOW YOUR WATER IS TREATED
The treatment process consists of a series of steps. Raw
water is drawn from Lily Pond and passed through
course and fine screens at our intake building. The
water continues to a mixing tank at the treatment facility
where ferric chloride, lime, sodium permanganate, and
polyaluminum chloride are added. The addition of
these chemicals converts the dissolved organic matter
naturally occurring in Lily Pond to small solid
particles. Gentle mixing, along with the addition of a
slight dosage of polymer helps these particles adhere to
one another, making them heavy enough to settle from
the treatment process. After settling the water is filtered
through layers of fine coal and silicate sand to reduce
turbidity (turbidity is a common measure of the clarity
of water). Following filtration, lime and phosphates
are added for corrosion control, chlorine for
disinfection, and fluoride to promote strong teeth. We
carefully monitor the amount of chlorine, adding the
lowest amount necessary to protect the safety of your
water without compromising taste. The water is then
pumped to water towers and into your home or
business.
FLUORIDATION
Fluoride is added to your drinking water to prevent
tooth decay and cavities. Fluoride has been added since
1952. Fluoride is a naturally occurring element in
many water supplies in trace amounts. In our system
the fluoride level is adjusted to an optimal level
averaging one part per million to improve oral health
in children. The Massachusetts DPH acceptable
range is 0.8 – 1.2 ppm. At this level it is safe,
odorless, colorless, and tasteless. There are over 3.9
million people in 140 Massachusetts water systems
and 184 million people in the United States who
receive the health and economic benefits of
fluoridation.
CROSS CONNECTIONS
The Cohasset Water Department has developed a State-
Mandated Cross Connection Control Program to control
potentially unhealthy connections to our water system. State
regulations currently control all non-residential facilities.
The following information is a brief overview of what a
cross connection is and how to prevent the unhealthy effects
of them.
What is a cross-connection?
A cross-connection is any temporary or permanent
connection between a public water system or consumer's
potable (i.e., drinking) water system and any source or
system containing non-potable water or other substances.
An example is the piping between a public water system or
consumer's potable water system and an auxiliary water
system (including wells), cooling system, or irrigation
system.
What is backflow?
Backflow is the undesirable reversal of flow of non-potable
water or other substances through a cross-connection and
into the piping of a public water system or consumer's
potable water system. There are two types of backflow:
backpressure backflow and backsiphonage. Backpressure
backflow is backflow caused by a downstream pressure that
is greater than the upstream or supply pressure in a public
Educational Statement Concerning Lead
If present, elevated levels of lead can cause serious health
problems, especially for pregnant women and young
children. Lead in drinking water is primarily from materials
and components associated with service lines and home
plumbing. Cohasset Water is responsible for providing high
quality drinking water, but cannot control the variety of
materials used in plumbing components. You can minimize
the potential for lead exposure by flushing your tap for 30
seconds to 2 minutes before using water for drinking and
cooking. If you are concerned about-lead in your water, you
may wish to have your water tested. Information on lead in
drinking water, testing methods, and steps you can take to
minimize exposure is available from the Safe Drinking Water
Hotline or at http://www.epa.gov/safewater/lead
page 3
water system or consumer's potable water system.
Backsiphonage is backflow caused by a negative pressure in
the water mains, causing water to flow from a customer’s
water system back into the public water mains.
What is a backflow preventer?
A backflow preventer is a method or mechanism to prevent
backflow. The basic method of preventing backflow is an
air gap, which is a physical separation of the public water
mains and the customers plumbing equal to two diameters of
the two pipes (this gap must be at least 1 inch) and eliminates
a cross-connection by provides a physical barrier to
backflow. The basic mechanism for preventing backflow is
a mechanical backflow preventer, which provides a physical
barrier to backflow.
What types of backflow assemblies, devices and methods
are permitted?
The following are types of permitted assemblies, devices and
methods: Air Gap, Atmospheric Vacuum Breaker, Double
Check Valve Assembly, Pressure Vacuum Breaker
Assembly, and Reduced Pressure Principle Backflow
Prevention Assembly. The choice of device or method
depends on the type of cross connection hazard that is
present.
Why do backflow preventers have to be tested
periodically?
Mechanical backflow preventers have internal seals, springs,
and moving parts that are subject to fouling, wear, or fatigue.
Also, mechanical backflow preventers and air gaps can be
bypassed. Therefore, all backflow preventers have to be
tested annually to ensure that they are functioning properly.
Specific Information about a Hose Bibb Atmospheric
Vacuum Breaker
A hose bib vacuum breaker should be attached to all
threaded hose bibs to which a hose can be connected (unless
it has a built-in vacuum breaker). Cross-connections with
hoses are probably the most prevalent cause of backflow and
the contamination of the water system. These devices do not
protect against back pressure, only siphonage. They should
be installed above the level of the hose being used and not
put under continuous pressure (more than 12 hours at a time)
For more information contact the Cohasset Water
Department at 781-383-0057.
WATER CONSERVATION TIPS
Install water-saving devices: You can save water by
installing low-flow showerheads, high-efficiency toilets,
and kitchen/bathroom faucet aerators.
Take shorter showers: Reduce your shower by 1 – 2
minutes and save 5 gallons!
Turn water off while brushing your teeth: Save 3 gallons!
Fix leaky faucets: Save up to 20 gallons a day!
Wash a full load of laundry: Save 15 – 50 gallons per
load!
Broom instead of Hose: You can save as much as 100
gallons of water by cleaning your driveway by sweeping
instead of using the hose.
Water before 8 a.m.: You can save about 25 gallons each
time you water, by watering before 8 a.m. – watering
early reduces evaporation and puts that water to work
helping your plants grow .
From Lawn to Xeriscape (low water use landscaping):
Switch your garden from turf to drought tolerant plants,
and reduce your household water use by more than
30% (http://www.allianceforwaterefficiency.org/Xeriscap
e_Water_Savings.aspx ).
page 4
2013 Cohasset Water Quality Results
The Cohasset Water Department tests for over 80 contaminants on a regular basis, in accordance with State and
Federal requirements. The following contaminants were the only ones detected in the most recent testing required.
Regulated Contaminants
Microbial
Contaminants
Date(s)
Sampled MCL MCLG
Highest
Level
Detected
Range of
Detection
Violation
?
(Y/N)
Possible Source(s) of
Contamination
Coliform Bacteria Monthly
One positive monthly
sample for systems that
collect less than 40
samples
0 1 0 - 1 N Naturally present in the environment
Health Effects: Total coliforms are bacteria that are naturally present in the environment and are used as a n indicator that other potentially
Harmful bacteria may be present.
Inorganic
Contaminants
Date(s)
Sampled
MCL MCLG Highest Level
Detected
Range of
Detection
Violation
(Y/N) Possible Source(s) of
Contamination
Fluoride (ppm) (1) Monthly 4 4 1.3 0-1.3 N Water additive which promotes
strong teeth.
Nitrate (ppm) 2013
10
.
0
3.3
0.14 – 3.3
N
Runoff from fertilizer use; Leaching
from septic tanks, sewage; Erosion
of natural deposits.
Barium (ppm) 4/09/13 2 2 0.013 N
Discharge of drilling wastes;
discharge from metal refineries;
erosion of natural deposits.
Perchlorate (ppb) 2013 2 N/A 0.24 N
Rocket propellants, fireworks,
munitions, flares, blasting agents.
(1) EPA set 4ppm as the MCL. Our state has a secondary level (SMCL) of 2ppm for fluoride to better protect human health.
Disinfectant and
Disinfection By-
Products
Date(s)
Collected
Highest Running
Average
Range
Detected
MCL
or
MRDL
MCLG or
MRDLG
Violation
?
(Y/N)
Possible Source(s) of
Contamination
Total Trihalomethanes
(TTHMs) (ppb)
Quarterly,
2013 70.4 15.6 - 112 80 No Byproduct of drinking water
chlorination
Haloacetic Acids
(HAA5’s) (ppb)
Quarterly,
2013 32.0 2.6 - 67 60 No Byproduct of drinking water
chlorination
Chlorine (ppm) (free) Monthly
2013 0.36 0.14 – 0.56 4 4 No Water additive used to control
microbes
Lead & Copper (2)
Date(s)
Collected
90th Percentile Action Level MCLG
# sites
above AL # sites
sampled Possible Sources of Contamination
Lead (ppb) Jul – Sep
2013
13
15 0
0 20
Corrosion of house hold plumbing
systems; Erosion of natural deposits
Copper (ppm) Jul – Sep
2013
0.2 1.3 1.3
0 20 Corrosion of household plumbing
systems; Erosion of natural deposits;
Leaching from wood preservatives
(2) Reduction in frequency for Lead & Copper sampling to every 3 years.
page 5
Turbidity TT
Lowest Monthly % of
Samples Highest Detected
Daily Value
Violation? Possible Sources of
Contamination
Daily Compliance (NTU) 0.3 0.24 No Soil Runoff
Monthly Compliance At least 95% 100% No
Turbidity is a measure of the cloudiness of the water. We monitor it because it is a good indicator of water quality.
*Monthly turbidity compliance is related to a specific treatment technique (TT). Our system filters the water so at least 95% of our samples each month must be
below the turbidity limits specified in the regulations.
Unregulated Contaminants (are those for which EPA has not established drinking water standards.
The purpose of unregulated contaminant monitoring is to assist EPA in determining their occurrence
in drinking water and whether future regulation is warranted.
Contaminants (units) Date(s)
Collected
Highest level
Detected
Range of
Detection
Average
Detected
SMCL Health
Advisory
ORSG Possible Source(s) of
Contamination
Chloroform (ppb) 2013
4.5 ND – 4.5
By-product of water chlorination
(regulated collectively with total
trihalomethanes, TTHMs) In non-
chlorinated sources, chloroform
may be naturally occurring.
Sodium (ppm) 8/27/2013
38
20 Natural sources; runoff from use
of salt on roadways; by-product of
treatment process.
Manganese (ppb) 7/19/2013 0.0 - 86 30 50 300 Erosion of natural deposits.
Sulfate (ppm) 8/27/2013
20
Health Effects Statements
“Manganese is a naturally occurring mineral found in rocks, soil, ground, and surface water. Manganese
is necessary for proper nutrition and is part of a healthy diet, but can have undesirable effects on certain
sensitive populations at elevated concentrations. The United States Environmental Protection Agency
(EPA) and MassDEP have set an aesthetics-based Secondary Maximum Contaminant Level (SMCL) for
manganese of 50 ug/L (micrograms per liter), or 50 parts per bil lion. In addition, EPA and MassDEP
have also established public health advisory levels. Drinking water may naturally have manganese
and, when concentrations are greater than 50 µg/L, the water may be discolored and taste bad. Over
a lifetime, EPA recommends that people drink water with manganese levels less than 300 µg/L and
over the short term, EPA recommends that people limit their consumption of water with levels over
1000 ug/L, primarily due to concerns about possible neurological effects. Children up to 1 year of
age should not be given water with manganese concentrations over 300 ug/L, nor should formula for
infants be made with that water for longer than 10 days. See:
http://www.epa.gov/safewater/ccl/pdfs/reg_determine1/support_cc1_magnese_dwreport.pdf.”
Sodium: Sodium sensitive individuals, such as those experiencing hypertension, kidney failure, or
congestive heart failure who drink water containing sodium should be aware of the sodium levels where
exposures are being carefully controlled.
page 6
Water Quality Definitions
90th Percentile. Out of every 10 homes, 9 were at or
below this level.
pCi/L . Picocuries per liter (radioactivity).
ppb - parts per billion, micrograms per liter (ug/I)
ppm - parts per million, milligrams per liter (mg/l)
AL (Action Level). The concentration of a contaminant that, if
exceeded, triggers treatment or other requirements which
must be followed.
MCL (Maximum Contaminant Level): Highest level
of contaminant allowed in drinking water. MCLs are set as
close to the MCLGs as feasible using the best available
treatment technology.
MCLG (Maximum Contaminant Level Goal): The level
of a contaminant in drinking water below which there is no
known or expected risk to health. MCLGs allow for margin
of safety.
MRDL (Maximum Residual Disinfectant Level). The
highest level of a disinfectant allowed in drinking water.
There is convincing evidence that addition of a disinfectant
is necessary for the control of microbiological
contamination.
MRDLG (Maximum Residual Disinfectant Level Goal).
Level of a drinking water disinfectant below which there
is no known or expected risk to health. MRDLGs do
not reflect the benefits of the use of disinfectants to
control microbial contaminants.
NTU (Nephelometric Turbidity Units) Measure of how
clear the water is
ND Not detected. Refers to the detection limit of the
chemical analysis instrument or procedure.
NR Not regulated (currently there is no MCL for this
compound).
ORSG. Mass Office of Research and Standards
Guideline
Concentration of a chemical in drinking water, at or
below which, adverse health are unlikel y to occur after
chronic lifetime) exposure.
SMCL. Secondary Maximum Contaminant Level These
standards protect the aesthetic qualities of drinking water and
are not health based.
TT (Treatment Technique) — A required process intended to
reduce the level of a contaminant in drinking water.
Variances & Exemptions — State or EPA permission not to
meet an MCL or a treatment technique under certain
conditions
“Drinking water, including bottled water, may reasonably be expected to contain at least small
amounts of some contamination. The presence of contaminants does not necessarily indicate that water
poses a health risk. More information about contaminants and potential health effects can be obtained
by calling the EPA’s Safe Drinking Water Hotline (1-800-426-4791.)”
Sources of Drinking Water and Drinking Water Contaminants
The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds,
reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it
dissolves naturally-occurring minerals and, in some cases, radioactive material, and can pick up
substances resulting from the presence of animals or from human activity.
Contaminants that may be present in source water include:
Microbial contaminants, such as viruses and bacteria, may come from sewage treatment plants, septic
systems, agricultural livestock operations, and wildlife.
Inorganic contaminants, such as salts and metals, can be naturally-occurring or result from urban
storm water runoff, industrial, or domestic wastewater discharges, oil and gas production, mining, and
farming.
Pesticides and herbicides may come from a variety of sources such as agriculture, urban storm water
runoff, and residential uses.
page 7
NOTICE
If you would like to have a hard copy of this report, please contact the
Cohasset Water Department at the telephone number in the report title and
one will be sent to you.
Organic chemical contaminants include synthetic and volatile organic chemicals that are by-products
of industrial processes and petroleum production, and can also come from gas stations, urban storm
water runoff, and septic systems.
Radioactive contaminants can be naturally occurring or be the result of oil and gas production, and
mining activities.
In order to ensure that tap water is safe to drink, the Department and EPA prescribe regulations that
limit the amount of certain contaminants in water provided by public water systems. FDA and the
Massachusetts Department of Public Health regulations establish limits for contaminants in bottled
water that must provide the same protection for public health