Is Harwich, MA Tap Water Safe to Drink?
Graded A+ — but Chromium-6 was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
95.9/100
waterverge.com Harwich, MA — Water Quality Report
Harwich's drinking water received a grade of A+ (95.9 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 39,144 residents using groundwater.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. PFAS testing under UCMR 5 found no detectable forever chemicals.
The system has 5 violations on record, including 3 health-based violations. 1 remains unresolved.
What to know about Harwich's water
Harwich ranks #2 out of 280 cities in Massachusetts for water quality, placing it one of the best in the state.
Harwich relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
Hexavalent chromium (chromium-6) was detected at 20.00 µg/L, above California's 10 µg/L limit. There is no federal MCL, but the EPA is reviewing evidence linking long-term exposure to cancer risk.
Water quality score
See methodology →Is Harwich, MA water safe to drink?
Harwich's tap water meets most EPA standards but has areas that warrant attention. With a grade of A+ (95.9/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 39,144 residents using groundwater (wells).
Recent water quality updates for Harwich
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Harwich's water quality assessment. Grade: A+ (95.9/100).
Federal disaster declaration (FEMA DR-3599). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4097). Hurricane event — may have impacted local water infrastructure.
1 health-based. Contaminants: Coliform (TCR).
1 health-based. Contaminants: Coliform (TCR).
1 health-based. Contaminants: Coliform (TCR).
Key contaminant findings
Based on the most recent EPA sampling data for Harwich's water supply.
Well within EPA limits.
The "Erin Brockovich" chemical. There is no federal MCL, but California has set a limit of 10 µg/L. Reverse osmosis filtration is effective at removing hexavalent chromium.
Violation history
Harwich's water system has 5 total violations on record, including 3 health-based violations. 1 remain unresolved.
Flood & environmental risk
Barnstable County has experienced 10 federally declared disasters since 1991. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Herring River.
Where does Harwich's water come from?
Harwich's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 39,144 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Herring River (river).
What Harwich residents can do
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Harwich's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Forever chemicals overview
National PFAS report →Violation summary
Violations & advisories
Drought conditions
D1 — moderate droughtBarnstable County is currently in D1 (moderate drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Flood & disaster history
Barnstable County has experienced 10 federally declared disasters since 1991. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.0 | 15 | ppb | Inorganic | Safe |
| 11Cl-PF3OUdS | ND | HI | µg/L | PFAS | Not Detected |
| 4:2 FTS | ND | HI | µg/L | PFAS | Not Detected |
| 6:2 FTS 6:2 FTSPFAS A fluorotelomer sulfonate commonly found at sites contaminated with aqueous film-forming foam (AFFF) used in firefighting. Health EffectsPotential liver toxicity and endocrine disruption. Less studied but identified as a contaminant of concern. EPA LimitNo individual MCL (not yet regulated) Common SourcesFirefighting foam (AFFF), airports, military bases, and industrial facilities. | ND | HI | µg/L | PFAS | Not Detected |
| 8:2 FTS | ND | HI | µg/L | PFAS | Not Detected |
| 9Cl-PF3ONS | ND | HI | µg/L | PFAS | Not Detected |
| ADONA | ND | HI | µg/L | PFAS | Not Detected |
| HFPO-DA HFPO-DA (GenX)PFAS A replacement for PFOA in manufacturing, marketed as safer but still a persistent "forever chemical." Also known as GenX. Health EffectsLiver and kidney effects, reproductive toxicity, immune system effects, and potential cancer risk. EPA Limit10 ppt MCL Common SourcesFluoropolymer manufacturing (used as PFOA replacement), industrial wastewater discharge. | ND | 0.01 | µg/L | PFAS | Not Detected |
| lithium LithiumInorganic A naturally occurring alkali metal found in groundwater. Monitored under UCMR 5 to assess occurrence in drinking water. Health EffectsKidney effects at high doses. Low-level exposure effects under study; some research suggests neurological effects. EPA LimitNo MCL (monitoring only under UCMR 5) Common SourcesNatural mineral deposits, geothermal water, and industrial discharge. | ND | HI | µg/L | PFAS | Not Detected |
| NEtFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| NFDHA | ND | HI | µg/L | PFAS | Not Detected |
| NMeFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| PFBA PFBAPFAS One of the shortest-chain PFAS compounds. Very mobile in water and difficult to remove with standard filtration. Health EffectsThyroid effects, potential developmental toxicity. Shorter half-life in body than long-chain PFAS. EPA LimitNo individual MCL (not yet regulated) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and firefighting foam. | ND | HI | µg/L | PFAS | Not Detected |
| PFBS PFBSPFAS A short-chain PFAS used as a replacement for PFOS. While it clears the body faster than long-chain PFAS, it still persists in the environment. Health EffectsThyroid effects, reproductive and developmental toxicity, kidney effects. EPA LimitPart of Hazard Index (1.0) Common SourcesIndustrial discharge, firefighting foam, and as a replacement chemical in manufacturing. | ND | HI | µg/L | PFAS | Not Detected |
| PFDA | ND | HI | µg/L | PFAS | Not Detected |
| PFDoA | ND | HI | µg/L | PFAS | Not Detected |
| PFEESA | ND | HI | µg/L | PFAS | Not Detected |
| PFHpA PFHpAPFAS A medium-chain PFAS compound found in various environmental samples. Less studied than PFOA/PFOS but still considered a contaminant of concern. Health EffectsLiver effects, potential developmental toxicity, and endocrine disruption. EPA LimitPart of Hazard Index (1.0) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and contaminated water sources. | ND | HI | µg/L | PFAS | Not Detected |
| PFHpS | ND | HI | µg/L | PFAS | Not Detected |
| PFHxA PFHxAPFAS A short-chain PFAS replacement chemical widely used after manufacturers phased out longer-chain PFAS. Very commonly detected in water. Health EffectsLiver and kidney effects, potential thyroid disruption. Considered less toxic than long-chain PFAS but still persistent. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial processes, firefighting foam (AFFF), food packaging, and textile treatment. | ND | HI | µg/L | PFAS | Not Detected |
| PFHxS PFHxSPFAS A medium-chain PFAS found in firefighting foam and consumer products. It has a long half-life in the human body, similar to long-chain PFAS. Health EffectsImmune system effects, thyroid disruption, and potential reproductive and developmental harm. EPA LimitPart of Hazard Index (1.0) Common SourcesFirefighting foam (AFFF), waterproof textiles, food packaging, and industrial discharge. | ND | HI | µg/L | PFAS | Not Detected |
| PFMBA | ND | HI | µg/L | PFAS | Not Detected |
| PFMPA | ND | HI | µg/L | PFAS | Not Detected |
| PFNA PFNAPFAS A long-chain PFAS compound used in manufacturing fluoropolymers. It bioaccumulates in the body and is very persistent in the environment. Health EffectsDevelopmental effects, liver toxicity, immune suppression, and potential cancer risk. EPA LimitPart of Hazard Index (1.0) Common SourcesFluoropolymer manufacturing, industrial emissions, and contaminated water sources. | ND | HI | µg/L | PFAS | Not Detected |
| PFOA PFOAPFAS A long-chain PFAS ("forever chemical") once widely used in nonstick coatings and firefighting foam. It persists in the body and environment for years. Health EffectsLinked to kidney and testicular cancer, thyroid disease, elevated cholesterol, and reproductive issues. EPA Limit4.0 ppt MCL Common SourcesIndustrial discharge, firefighting foam (AFFF), nonstick cookware manufacturing, and contaminated groundwater. | ND | 0.004 | µg/L | PFAS | Not Detected |
| PFOS PFOSPFAS A long-chain PFAS compound historically used in stain-resistant coatings and firefighting foam. One of the most studied and persistent PFAS chemicals. Health EffectsLiver damage, immune system suppression, thyroid disruption, increased cholesterol, and potential cancer risk. EPA Limit4.0 ppt MCL Common SourcesFirefighting foam (AFFF), industrial sites, stain-resistant fabric treatments, and contaminated groundwater. | ND | 0.004 | µg/L | PFAS | Not Detected |
| PFPeA PFPeAPFAS A short-chain PFAS compound commonly detected in drinking water. One of the most frequently found PFAS in UCMR 5 monitoring. Health EffectsLess studied than PFOA/PFOS. Potential liver and thyroid effects. Research is ongoing. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial discharge, firefighting foam degradation, and consumer products. | ND | HI | µg/L | PFAS | Not Detected |
| PFPeS | ND | HI | µg/L | PFAS | Not Detected |
| PFTA | ND | HI | µg/L | PFAS | Not Detected |
| PFTrDA | ND | HI | µg/L | PFAS | Not Detected |
| PFUnA | ND | HI | µg/L | PFAS | Not Detected |
Lead level trend (90th percentile)
See how Harwich compares by contaminant
Explore where Harwich ranks among all Massachusetts cities for specific contaminants.
Water source & infrastructure
Where Harwich's water comes from
Harwich's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by local government ownership and serves approximately 39,144 people through 1 water system.
Water bodies near Harwich
Harwich is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Harwich
| System Name | PWSID | Population | Source |
|---|---|---|---|
| HARWICH WATER DEPARTMENT | MA4126000 | 39,144 | GW |
How Harwich compares
Full Massachusetts rankings →Harwich's score of 95.9/100 is above the average of 80/100 among major Massachusetts cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Massachusetts rankings →About Harwich, MA
Wikipedia →Harwich is a town on Cape Cod in Massachusetts. At the 2020 census it had a population of 13,440. Harwich experiences a seasonal increase to roughly 37,000. The town is a popular vacation spot, located near the Cape Cod National Seashore. Harwich's beaches are on the Nantucket Sound side of Cape Cod. Harwich has three active harbors. Saquatucket, Wychmere and Allen Harbors are all in Harwich Port. The town of Harwich includes the villages of Pleasant Lake, West Harwich, East Harwich, Harwich Port, Harwich Center, North Harwich, Northwest Harwich, and South Harwich. It is named after the English town of Harwich.
Learn more about your water
Guides and resources related to Harwich's water quality findings.
Explore water quality across Barnstable
Frequently asked questions
Is Harwich, MA tap water safe to drink?
Harwich's water quality earned a grade of A+ (95.9/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #2 out of 280 cities tested in Massachusetts.
What contaminants are in Harwich's water?
Lead was measured at 0.0 ppb (90th percentile). No PFAS compounds were detected. 5 violations are on record.
How is Harwich's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Harwich?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Harwich's water come from?
Harwich's water is sourced from Groundwater. The city has 1 water system serving approximately 39,144 residents.
What health violations has Harwich's water system had?
Harwich has 3 health-based violations on record. The most recent violation was recorded in September 2000. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 1 violation remains unresolved.
Is Harwich's groundwater at risk of contamination?
Harwich uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 5 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Harwich's water compare to other cities?
Harwich ranks #2 out of 280 cities in Massachusetts (better than 99% of state cities) and #251 out of 15744 cities nationally (98th percentile). The grade of A+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.