2007

The sources of the Williamsburg water supply are two gravel pack wells.  The pump house located near the intersection of Mount Vernon Drive and Valley Forge Drive in Pelham, NH.  Treatment consist of chlorine addition to kill bacteria and sodium hydroxide to raise the pH to aid in corrosion control.
WILLIAMSBURG
EPA # 1851010
Inorganic Contaminants	Units	MCLG	MCL	Level Detected	Range	Year	Violation Yes/No	Typical Source of Contaminant
Barium	ppm	2	2	0.018	n/a	2006	NO	Discharge from drilling wastes; discharge from metal refineries; erosion of natural deposits
Nitrate as Nitrogen	ppm	10	10	3.94	n/a	2006	NO	Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits.
Volatile Organic Contaminants	Units	MCLG	MCL	Level  Detected	Range	Year	Violation Yes/No	Typical Source of Contaminant
Total Trihalomethanes (TTHMs)	ppb	0	80	14.0	n/a	2006	NO	By-product of drinking water chlorination.
Haloacetic Acids (HAA5)	ppb	0	60	5.8	n/a	2004	NO	By-product of drinking water chlorination.
Volatile Organic Contaminants	Units	MRDLG	MRDL	Average Level  Detected	Range	Year	Violation Yes/No	Typical Source of Contaminant
Chlorine	ppm	4	4	0.36	nd to 0.6	2006	NO	Water additive used to control microbes
Inorganic Contaminants	Units	MCLG	AL	90th percentile sample value	# sites above AL	Year	Violation Yes/No	Typical Source of Contaminant
Lead	ppb	0	15	6	0 of 5	2006	NO	Corrosion of household plumbing system
Copper	ppm	1.3	1.3	0.66	0 of 5	2006	NO	Corrosion of household plumbing system
Radiological Contaminants	Units	MCLG	MCL	Level Detected	Range	Year	Violation Yes/No	Typical Source of Comtamination
Gross Alpha (Compliance)	pCi/L	0	15	0.2	n/a	2003	NO	Erosion of natural deposits
Radon	pCi/L	Not Regulated		482	n/a	2003	n/a	Erosion of natural deposits
Radon is a radioactive gas that you can't see, taste or smell.  It can move up through the ground and into a home through cracks and holes in the foundation.  Radon can also get into indoor air when released from tap water from showering, washing dishes, and other household activities.  It is a known human carcinogen.  Breathing radon can lead to lung cancer.  Drinking water containing radon may cause an increased risk of stomach cancer.  Presently EPA is reviewing a standard for radon in water.
Source Assessment Information
		Summary of Susceptibility Factors
Source Name	Date	Low	Med	High
Gravel Pack Well 1	3/2/01	7	4	1
Gravel Pack Well 1A	3/2/01	7	4	1
The complete Assessment Report is available for inspection.  For more information call Gary Tetley or visit NH DES's Drinking Water Source Assessment Program web site at www.des.state.nh.us/dwspp