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Harwich Water Department

Harwich, MA · serves 40,062 · GroundwaterMA4126000
All clear
All monitored contaminants within federal limits. Last updated from the most recent CCR and EPA monitoring data available.
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Measured in your 2025 water report
From your utility's Consumer Confidence Report · 23 contaminants tested
Above limit
Approaching limit
Within limits
Regulated contaminants — legally enforceable limits
Nitrate (as N)▸
1.8 mg/L
What is it?
Comes from fertilizer runoff, septic systems, and erosion of natural deposits. One of the most common groundwater contaminants in agricultural areas.
Why it matters
Nitrate above 10 mg/L can cause "blue baby syndrome" (methemoglobinemia) in infants under 6 months — it interferes with blood's ability to carry oxygen. Adults can tolerate higher levels.
What to do
If you have an infant on formula and your water is above 5 mg/L, consider using bottled water for formula preparation. Boiling water does NOT remove nitrate — it concentrates it.
What the research says
Multiple peer-reviewed studies have found neural tube defects, preterm birth, and low birth weight at concentrations as low as 5 mg/L — 2x below the US federal limit.
Perchlorate▸
0.19 µg/L
No additional information available for this contaminant.
Lead & copper — tested at your tap
Copper▸
0.025 mg/L
What is it?
Leaches from copper household plumbing and pipes. Some copper is a normal part of drinking water infrastructure.
Why it matters
Short-term exposure above the action level of 1.3 mg/L can cause gastrointestinal distress. Long-term exposure can cause liver and kidney damage. At typical detected levels (well below the AL), copper is not a health concern.
What to do
If above the action level, run your tap for 30 seconds before drinking. Copper levels decrease as water flows through the pipes.
Disinfection byproducts
DBAA▸
1.59 µg/L
What is it?
A brominated haloacetic acid formed in chlorinated water with elevated bromide. One of five HAAs regulated together as HAA5.
Why it matters
EPA has not established an individual MCLG for DBAA — there isn't enough data yet to identify a no-effect level. Regulated as part of HAA5 (60 µg/L), since the group is associated with cancer and developmental concerns.
What to do
Reduced by point-of-use carbon-block filtration (NSF/ANSI 53). Source-water treatment is the more effective control.
HAA5▸
1.59 µg/L
What is it?
Another group of disinfection byproducts formed when chlorine reacts with natural organic matter. HAA5 measures the five most common species.
Why it matters
Long-term exposure above the MCL of 60 µg/L (0.060 mg/L) is associated with increased cancer risk. Like THMs, the MCL is based on a running annual average.
What to do
Activated carbon filters can reduce HAA5. If your system consistently approaches the limit, a reverse osmosis filter provides more complete removal.
DBCM▸
2.5 µg/L
What is it?
A brominated trihalomethane formed when chlorine reacts with bromide-containing organic matter. More common in source waters with higher bromide levels — often coastal or groundwater systems.
Why it matters
EPA sets the MCLG at 0.06 mg/L based on liver and kidney effects. Some evidence suggests DBCM may be carcinogenic, though the data is less clear than for BDCM and bromoform. Regulated together with the other three trihalomethanes under TTHM.
What to do
Like other THMs, DBCM forms in the distribution system as chlorine reacts over time. A point-of-use carbon-block filter (NSF/ANSI 53) reduces it along with related compounds.
Chloroform▸
1.5 µg/L
What is it?
A disinfection byproduct formed when chlorine reacts with naturally occurring organic matter in source water. The most common of the four trihalomethanes.
Why it matters
Long-term exposure has been associated with increased risk of bladder cancer and possibly colorectal cancer. EPA classifies it as a probable human carcinogen and sets an MCLG of 0.07 mg/L based on liver effects. Regulated together with three other trihalomethanes under the TTHM standard (80 µg/L).
What to do
Chloroform levels are largely a function of how your utility manages disinfection. If TTHM is approaching the limit, a carbon-block filter (NSF/ANSI 53 certified for VOCs or specifically for trihalomethanes) at point-of-use reduces it. Letting cold water run for 30 seconds before drinking can also help, since chloroform forms in the distribution system.
BDCM▸
1.3 µg/L
What is it?
A brominated trihalomethane formed when chlorine reacts with organic matter and bromide in source water. One of four trihalomethanes regulated together under TTHM.
Why it matters
EPA classifies BDCM as a probable human carcinogen and sets the MCLG at zero, meaning the agency identifies no safe lifetime exposure level. Studies link it to bladder and colon cancer, and to reproductive and developmental effects at high exposures. The enforceable limit (80 µg/L for total TTHM) reflects what's feasible to achieve, not what's safest.
What to do
BDCM is formed in your utility's system, so reducing it generally means reducing total disinfection byproducts there. At point-of-use, a carbon-block filter certified for VOCs or trihalomethanes (NSF/ANSI 53) reduces BDCM along with other THMs.
Bromoform▸
2 µg/L
What is it?
A fully brominated trihalomethane, formed when chlorine reacts with high-bromide source water. More common in coastal and arid-region systems where source water naturally contains bromide.
Why it matters
EPA classifies bromoform as a probable human carcinogen, with an MCLG of zero. Animal studies show liver and intestinal tumors; human evidence is more limited but consistent with the other brominated THMs. Regulated under the TTHM standard (80 µg/L for the sum of all four).
What to do
Reducing bromoform usually means working at the source — your utility may need to adjust disinfection or pretreatment. At home, an NSF/ANSI 53 carbon-block filter reduces bromoform along with the other THMs.
TTHM▸
7 µg/L
What is it?
Formed when chlorine used to disinfect water reacts with natural organic matter. Includes chloroform, bromoform, and related compounds. The trade-off: disinfection prevents waterborne disease, but creates these byproducts.
Why it matters
Long-term exposure above the MCL of 80 µg/L (0.080 mg/L) is associated with increased cancer risk and possible reproductive effects. The MCL is based on a running annual average, not a single sample.
What to do
If your system is near or above the limit, an activated carbon filter (including pitcher filters like Brita) can reduce THMs. Running water for a minute before drinking also helps, as THMs are volatile and dissipate.
% of limit

Other measurements

These describe characteristics of the water that aren’t health risks at typical levels — mineral content, taste, hardness, and similar.

Hardness
▸
26 mg/L· soft
pH
▸
6.5 SU· acidic
Alkalinity
▸
51 mg/L
Aluminum
▸
0.03 mg/L
(EPA secondary standard: 0.2 mg/L)
Calcium
▸
6.6 mg/L
Chloride
▸
41 mg/L
(EPA secondary standard: 250 mg/L)
Iron
▸
0.15 mg/L
(EPA secondary standard: 0.3 mg/L)
Magnesium
▸
3.1 mg/L
Manganese
▸
0.046 mg/L
(EPA secondary standard: 0.05 mg/L)
Potassium
▸
28 mg/L
Specific Conductance
▸
260 µmhos/cm
(EPA secondary standard: 1600 µmhos/cm)
Sulfate
▸
10 mg/L
(EPA secondary standard: 250 mg/L)

CCR data in early access — values are extracted from utility PDFs and may contain errors. Verify with your utility's 2025 CCR report.

Source: HARWICH WATER DEPARTMENT Consumer Confidence Report 2025 · Extracted by WaterScore
Measured data
Private Well Risk

Do you have or use a private well? Measured concentrations from nearby private wells sampled within 5 miles.

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14 wells
Water Sources

Harwich pumps water from 14 groundwater wells drawing from local groundwater.

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