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Maximum Contaminant Level (MCL):

The level that can not be exceeded by public water systems.

Secondary Maximum Contaminant Level (SMCL):

The threshold level for aesthetic concerns; taste, odor and staining.

Action Level (AL):

90% of samples must fall below this level, pertains mainly to public water supplies.


MCL = 0.01 mg/L
The U.S. Environmental Protection Agency (EPA) has set the health standard at 0.010mg/L. Some of the health effects are skin irritation, skin cancer, liver and kidney damage and damage to the central nervous system. Its origin in New Hampshire drinking water is not fully known, but could come from the bedrock in the state, or of man-made sources such as metal refining processes or pesticides.


SMCL = 250 mg/L
Though chloride is not considered a health hazard, the standard has been set at the level at which the average person notices a salty taste. Chloride is associated with infiltration of road de-icing salt, backwash from a water softener and sea water.


AL = 1.3 mg/L
SMCL = 1.0 mg/L
The high copper concentrations in New Hampshire are almost always a result of corrosive water picking up copper from plumbing lines. The acceptable limit is set at 1.0 mg/L. Water above the limit may have an unpleasant taste and cause blue or green staining on water use fixtures.


MCL = 4.0 mg/L
Fluoride is widely used to prevent tooth decay, but in excess it can cause spotted or pitted teeth, called fluorosis. Recommended adult intake of fluoride is 1.0-2.5 mg per day. Children are often given a supplement if the fluoride level in their home drinking water is not sufficient.

Gross Alpha Radionuclides

MCL = 15 pCi/L
There are several radioactive elements that naturally occur in some of New Hampshire's groundwater. These elements emit alpha particles and are believed to be carcinogenic. The gross alpha test is a "total" measurement of the alpha emitting particles including both radium and uranium. There is a unique protocol used to determine if the gross alpha MCL of 15 pCi/L has been exceeded This requires the subtraction of the uranium alpha particle amount from the gross alpha result. Therefore, if your gross alpha result exceeds 15 pCi/L, further analysis for uranium is recommended.Because the MCL for the element radium is 5 pCi/L, if your gross alpha result exceeds 5 pCi/L, further analysis for radium is recommended.


See below
The contributors to hardness are calcium and magnesium. The presence of these elements in general is not a health hazard, but hardness elements tend to plate out on water pipes and heating coils in hot water tanks, and reduce the effectiveness of detergents.
Low (Soft)
0 - 75 mg/L
76 - 150 mg/L
151 - 250 mg/L
Very Hard
251+ mg/L
Water treatment companies often express hardness in grains per gallon (gpg). 1 gpg equals 17.1 mg/L


SMCL = 0.30mg/L
Over 0.30 mg/L, iron becomes a nuisance element. It will show its presence as rust stains on water fixtures and if chlorine bleach is used in the laundry, rust spots will appear on clothes. If this happens, use a non-chlorine bleach with your clothes. Common iron removal methods include ion exchange and oxidation filtration.


AL = 0.015 mg/L
Chronic ingestion of lead has been associated with a large number of harmful health effects, and therefore water with excessive lead levels should not be consumed. High levels can be attributed to old lead piping, lead solder used on copper piping and some installed pumps. In most cases, lead in your drinking water can be reduced by running the water before filling a glass to drink. pH, alkalinity and hardness correction will reduce corrosion damage.


SMCL = 0.05 mg/L
Over 0.05 mg/L manganese becomes a nuisance element and its presence is detected by purplish black staining of kitchen and bathroom fixtures. The 0.05 mg/L SMCL is the threshold for staining by most humans. Above this level your drinking water would have an oily vinyl or metallic taste. A "rotten egg" smell, due to the presence of hydrogen sulfide is often associated with a high iron and manganese level, which tends to disappear when the iron and manganese are removed. Manganese is also an essential nutrient for humans at approximately 5 mg per day.


SMCL = 250 mg/L
MtBE is the abbreviation for the compound methyl tertiary butyl ether. This compound is a colorless liquid at room temperature and pressure. MtBE is a man-made material and thus its presence in water would indicate that man-made contamination exists in the recharge area of the well. MtBE degrades very slowly, is highly soluble in water, has a very small molecular structure and very low taste and odor thresholds.
MtBE increases the octane rating of gasoline and reduces air pollution by also increasing gasoline's oxygen level. Higher oxygen levels are required by the reformulated gasoline (RFG) provisions of the 1990 Clean Air Act. This requirement lead to an increase in the percentage of MtBE in gasoline in 1995. There are few other uses of MtBE in normal commerce or industry. The use of MtBE in gasoline began in the late 1970s and early 1980s as a substitute for lead. Thus MtBE contamination is relatively recent in origin.
The U.S. Environmental Protection Agency (EPA) has not set a formal drinking water health related standard, known as a maximum contaminant level (MCL), for MtBE. The New Hampshire Office of Community and Public Health, Bureau of Health Risk Assessment (BHRA) has developed a health related drinking water guideline for MtBE. The guideline recommends that water should not be consumed if the level of MtBE is 70 micrograms per liter or greater. Studies with animals suggest drinking water with high levels of MtBE may cause stomach irritation, liver and kidney damage and nervous system effects. An increased amount of liver and kidney cancer was found in rats and mice breathing high levels of MtBE.

Nitrate / Nitrite

MCL = 10 mg/L
MCL = 1 mg/L
The presence of nitrate and nitrite generally indicates contamination from a pasture, manure pile, decomposed vegetation or fertilized agricultural land. Nitrates change to nitrites in the body, which reduces oxygen uptake by the hemoglobin. Boiling water will not help, it will only concentrate the nitrates.


Recommended 6.5 - 8.5
pH is a measure of acidity of a sample. The scale is 0-14. A reading to 0-7 is acidic, 7-14 is basic (or alkaline), and 7 is neutral. Acidic water, along with low hardness (soft water), tends to be corrosive to your water pipes, potentially dissolving lead and copper. Basic water itself is not a problem, but may have a bitter taste. Alkalinity, which is a separate measurement, is your water's capacity against drastic pH changes.


MCL = 5 pCi/L
A naturally occurring radioactive contaminant that occurs primarily in ground water. It has been found to cause bone cancer in humans at high exposure levels, and possibly other cancers as well.


SMCL = 250 mg/L
Some sodium is found in all natural water supplies, but more so in areas where sea water and road salt seep into the ground. Sodium has no set health hazard level, but those individuals on a low sodium diet should take into account the amount of sodium in their water when determining overall sodium intake.

Total coliform
E. Coli
E. Coli (swimming water)
Presence is unacceptable
Presence is unacceptable
Recommended level
< 88 cts / 100 ml
Total coliform are a group of bacteria with common characteristics used to indicate unacceptable drinking water quality. Within the total coliform group, the E. Coli bacteria are specifically used to indicate fecal contamination. High non-coliform levels are usually from the drilling of the well or an indication of surface water intrusion. When non-coliform are greater than 200 CTS per 100ml they can obscure the growth of coliform.
If total coliform, especially E. Coli and/or high non-coliform counts are present in a well, it needs to be checked for construction problems. It is very common for new or modified wells to have unacceptable bacteria levels, and often it is necessary to disinfect with bleach or chlorine tablets more than once. If you have a positive total coliform, E. Coli or high non-coliform count, you should have received an Unacceptable Bacteria Notification which includes disinfecting instructions.


A naturally occurring radioactive contaminant that occurs in both ground water and surface water. It has been found to cause bone cancer in humans at high exposure levels, and is believed to be toxic to kidneys.

Volatile Organic Compounds

Volatile Organic Compounds (VOCs) includes a variety of chemicals, some of which may have short and long term health effects. The presence of VOCs may be indicative of a well contaminated by petroleum products, industrial solvents or byproducts from the process of disinfecting a well. The presence of these compounds is potentially a health risk.