Contaminants Detected
EXCEED GUIDELINES
Chromium (hexavalent)
Potential Effect: cancer

This Utility: 0.0451 ppb
No Legal Limit
2.3x
EWG's Health Guideline: 0.02 ppb
Chromium (hexavalent)
Chromium (hexavalent) is a carcinogen that commonly contaminates American drinking water. Chromium (hexavalent) in drinking water may be due to industrial pollution or natural occurrences in mineral deposits and groundwater. Read more about chromium (hexavalent).
Chromium (hexavalent) was found at 2.3 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 0.02 ppb for chromium (hexavalent) was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.
Legal Limit
None
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2023.
ppb = parts per billionPollution Sources
Industry
Naturally Occurring
Filtering Options
Reverse Osmosis
Ion Exchange
Haloacetic acids (HAA9)
Potential Effect: cancer

This Utility: 3.06 ppb
No Legal Limit
51x
EWG's Health Guideline: 0.06 ppb
Haloacetic acids (HAA9)
Haloacetic acids are formed when disinfectants such as chlorine are added to tap water. The group of nine haloacetic acids includes monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid, which are regulated as a group by the federal government (HAA5); and bromochloroacetic acid, bromodichloroacetic acid, chlorodibromoacetic acid, and tribromoacetic acid.
Haloacetic acids (HAA9) was found at 51 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 0.06 ppb for the group of nine haloacetic acids, or HAA9, was defined in a peer-reviewed scientific study by EWG and represents a one-in-a-million lifetime cancer risk level as . This health guideline protects against cancer.
Legal Limit
None
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2018-2021.
ppb = parts per billionPollution Sources
Treatment Byproducts
Filtering Options
Activated Carbon
Reverse Osmosis
Perfluorooctanoic acid (PFOA)
Potential Effect: cancer

This Utility: 2.30 ppt
Proposed Legal Limit: 4 ppt
26x
EWG's Health Guideline: 0.09 ppt
Perfluorooctanoic acid (PFOA)
Perfluorooctanoic acid (PFOA) is a member of a group of perfluorinated chemicals used in many consumer products. PFOA and other perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.
Perfluorooctanoic acid (PFOA) was found at 26 times above EWG's Health Guideline.
EWG Health Guideline
This Utility
Proposed Legal Limit
National Average
State Average
Health Risks
The EWG Health Guideline of 0.09 ppt for PFOA was was defined by EPA's final toxicity value from the Office of Water’s Final Human Health Toxicity Assessment. This health guideline protects againat cardiovascular harm and harm to fetal growth.
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2024.
ppt = parts per trillionPollution Sources
Industry
Runoff & Sprawl
Filtering Options
Activated Carbon
Reverse Osmosis
Includes chemicals detected in 2021-2023 for which annual utility averages exceeded an EWG-selected health guideline established by a federal or state public health authority.
OTHER DETECTED
1,4-Dioxane

This Utility: 0.0248 ppb
No Legal Limit
EWG's Health Guideline: 0.35 ppb
1,4-Dioxane
1,4-Dioxane is a solvent classified by the EPA as a likely human carcinogen. It contaminates groundwater in many states due to industrial wastewater discharges, plastic manufacturing runoff and landfill runoff.
How your levels compare
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 0.35 ppb for 1,4-dioxane was defined by the Environmental Protection Agency as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.
Legal Limit
None
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2023.
ppb = parts per billionPollution Sources
Industry
Runoff & Sprawl
Filtering Options
Reverse Osmosis
Chlorate

This Utility: 124.1 ppb
No Legal Limit
EWG's Health Guideline: 210 ppb
Chlorate
Chlorate forms in drinking water as a byproduct of disinfection. Chlorate impairs thyroid function, making chlorate exposure most harmful during pregnancy and childhood.
How your levels compare
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 210 ppb for chlorate was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against hormone disruption.
Legal Limit
None
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2023.
ppb = parts per billionPollution Sources
Agriculture
Industry
Treatment Byproducts
Manganese

This Utility: 11.2 ppb
No Legal Limit
EWG's Health Guideline: 100 ppb
Manganese
Manganese is a naturally occurring element that is common in food and drinking water. Excessive manganese exposures may impair children's attention, memory and intellectual capacity. Click here to read more about manganese.
How your levels compare
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 100 ppb for manganese was defined by the state of Minnesota as a health risk limit, the concentration of a contaminant that can be consumed with little or no risk to health. This health guideline protects against harm to the brain and nervous system.
Legal Limit
None
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2023.
ppb = parts per billionPollution Sources
Industry
Naturally Occurring
Filtering Options
Ion Exchange
Perfluorobutanoic Acid (PFBA)*

This Utility: 0.291 ppt
No Legal Limit
EWG's Health Guideline: 1,000 ppt
Perfluorobutanoic Acid (PFBA)
Perfluorobutanoic acid (PFBA) is a member of a group of perfluorinated chemicals used in many consumer products. PFOS and other perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.
How your levels compare
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 1,000 ppt for perfluorobutanoic acid was defined by EPA's recommended application of the toxicity value for PFHxA published in the Integrated Risk Information System’s toxicological review. This health guideline protects against harm to fetal growth and child development.
Legal Limit
None
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2018-2024.
ppt = parts per trillionPollution Sources
Industry
Runoff & Sprawl
Filtering Options
Activated Carbon
Reverse Osmosis
Perfluorohexanoic Acid (PFHxA)*

This Utility: 0.661 ppt
No Legal Limit
EWG's Health Guideline: 1,000 ppt
Perfluorohexanoic Acid (PFHxA)
Perfluorohexanoic acid is a member of a group of perfluorinated chemicals used in many consumer products. Perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.
How your levels compare
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 1,000 ppt for perfluorohexanoic acid was defined by EPA's toxicity value published in the Integrated Risk Information System's toxicological review. This health guideline protects against harm to fetal growth and child development.
Legal Limit
None
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2018-2024.
ppt = parts per trillionPollution Sources
Industry
Runoff & Sprawl
Filtering Options
Activated Carbon
Reverse Osmosis
Strontium

This Utility: 0.0537 ppb
No Legal Limit
EWG's Health Guideline: 1,500 ppb
Strontium
Strontium is a metal that accumulates in the bones. Radioactive strontium-90 can cause bone cancer and leukemia, and any form of strontium at high doses can harm bone health.
How your levels compare
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 1,500 ppb for strontium was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against harm to bones.
Legal Limit
None
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2023.
ppb = parts per billionPollution Sources
Industry
Naturally Occurring
Filtering Options
Reverse Osmosis
Ion Exchange
Vanadium

This Utility: 0.261 ppb
No Legal Limit
EWG's Health Guideline: 21 ppb
Vanadium
Vanadium is a metal used in steels and other alloys. People are commonly exposed to vanadium in water and food. Excessive exposure can be toxic during pregnancy and childhood.
How your levels compare
EWG Health Guideline
This Utility
National Average
State Average
Health Risks
The EWG Health Guideline of 21 ppb for vanadium was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against change in blood chemistry.
Legal Limit
None
Understanding the Data
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2013-2023.
ppb = parts per billionPollution Sources
Industry
Naturally Occurring
Filtering Options
Ion Exchange
Includes chemicals detected in 2021-2023 for which annual utility averages were lower than an EWG-selected health guideline established by a federal or state public health authority.
Other Contaminants Tested
✕Chemicals tested for but not detected:
1,1-Dichloroethane, 1,2,3-Trichloropropane, 1,3-Butadiene, 1-butanol, 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic aci, 2-methoxyethanol, 2-propen-1-ol, 4,8-dioxa-3H-perfluorononanoic acid (ADONA), 4:2 Fluorotelomer Sulfonic Acid (4:2 FTSA), 6:2 Fluorotelomer Sulfonic Acid (6:2 FTSA), 8:2 Fluorotelomer Sulfonic Acid (8:2 FTSA), 9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (, Alpha-hexachlorocyclohexane, Bromochloromethane, Bromoform, Bromomethane, Butanoic acid, 2,2,3,3,4,4-hexafluoro-4-(trifluoro, Butylated hydroxyanisole, Chlorodifluoromethane, Chloromethane, Chlorpyriphos, Cobalt, Dibromoacetic acid, Dimethipin, Ethoprop, Germanium, Hexafluoropropylene oxide dimer acid (HFPO-DA), Lithium, Molybdenum, Monobromoacetic acid, Monochloroacetic acid, N-ethyl perfluorooctane sulfonamido acetic acid (N, N-methyl perfluorooctanesulfonamidoacetic acid, Nonafluoro-3,6-dioxaheptanoic acid, o-toluidine, Oxyflurofen, Perfluoro(2-ethoxyethane)sulfonic acid, Perfluorobutane sulfonate (PFBS), Perfluorobutanoic acid (PFBA), Perfluorodecanoic acid (PFDA), Perfluorododecanoic acid (PFDoA), Perfluoroheptane sulfonic acid (PFHpS), Perfluoroheptanoic acid (PFHPA), Perfluorohexane sulfonate (PFHXS), Perfluorohexanoic Acid (PFHxA), Perfluorononanoic acid (PFNA), Perfluorooctane sulfonate (PFOS), Perfluoropentane sulfonic acid (PFPeS), Perfluoropentanoic acid (PFPeA), Perfluorotetradecanoic acid (PFTA), Perfluorotridecanoic acid (PFTrDA), Perfluoroundecanoic acid (PFUnA), Permethrin, Profenofos, Propanoic acid, 2,2,3,3-tetrafluoro-3-(trifluorome, Quinoline, Tebuconazole, Tribufos
Find A Filter
Utility:
Derry Water DepartmentCarbon Filters
FILTERS 2 contaminants exceeding guidelines (+2 others)
Can reduce the levels of many common contaminants.
pros
- Lower upfront cost
- Reduced maintenance
cons
- Does not remove all contaminants
Reverse Osmosis
FILTERS 3 contaminants exceeding guidelines (+4 others)
Can reduce the levels of many common contaminants.
pros
- Most effective
cons
- Higher upfront cost
- Requires more maintenance
- Wastes water
Other Considerations
Ion Exchange
Pros: Softens hard water, Reduces some contaminants
Cons: Doesn’t remove all contaminants
Whole-House Filters
Pros: Useful for reducing radiologicals and TCE
Cons: Expensive to install and maintain, Risk of bacterial contamination
Distillation
Pros: Removes heavy metals and harmful microbes
Cons: Does not reduce most contaminants
Explore filter options for each contaminant. See which technologies are effective at reducing specific contaminants to help you make an informed decision on the best water treatment solution for your needs.
CONTAMINANTS ABOVE HEALTH GUIDELINES | activated carbon | reverse osmosis | ion exchange |
Chromium (hexavalent) | |||
Haloacetic acids (HAA9) | |||
Perfluorooctanoic acid (PFOA) | |||
OTHER CONTAMINANTS DETECTED | activated carbon | reverse osmosis | ion exchange |
1,4-Dioxane | |||
Chlorate | |||
Manganese | |||
Perfluorobutanoic acid (PFBA) | |||
Perfluorohexanoic Acid (PFHxA) | |||
Strontium | |||
Vanadium |