2007

The sources of the Redfield Estates water supply include two wells located near the lower pump station off Redfield Circle in East Derry, NH.  Well # 1 is located 10 feet north of the pump house and well # 4 is located 1,000 feet southeast of the pump house.  Additional sources are six wells located in the Drew Wood system off Olsen Rd. near Drew Woods Dr. in East Derry, NH.  Treatment consist of chlorine addition to kill bacteria and phosphate addition to sequester iron and mangannese and provide corrosion control.
REDFIELD ESTATES
EPA # 0612080
Microbiological Contaminants	Units	MCLG	MCL	Highest monthly # of positive samples		Month	Violation Yes/No	Typical Source of Contaminant
Total Coliform Bacteria	Positive/Negative	Negative	> 1 positive per month	1		OCT	NO	Naturally present in the environment
Inorganic Contaminants	Units	MCLG	MCL	Level Detected	Range	Year	Violation Yes/No	Typical Source of Contaminant
Fluoride	ppm	4	4	0.34	n/a	2006	NO	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	n /a	80	7.8	n/a	2006	NO	By-product of drinking water chlorination.
Haloacetic Acids (HAA5)	ppb	n/a	60	3.5	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	0.38	0.0 to 0.65	2006	NO	Water additive used to control microbes
Radiological Contaminants	Units	MCLG	MCL	Highest Level Detected	Range	Year	Violation Yes/No	Typical Source of Contaminant
Gross Alpha (Compliance)	pCi/L	0	15	4.3	nd to 4.3	2005	NO	Erosion of natural deposits
Combined Radium	pCi/L	0	5	1.4	0.5 to 1.4	2005	NO	Erosion of natural deposits
Uranium	ppb	0	30	5.8	4.0 to 5.8	2005	NO	Erosion of natural deposits
Radon	pCi/L	Not Regulated		2,160	n/a	2006	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.
Inorganic Contaminants	Units	MCLG	AL	90th percentile sample value	# samples 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	0.12	0 of 5	2006	NO	Corrosion of household plumbing system
Source Assessment Information
		Summary of Susceptibility Factors
Source Name	Date	Low	Med	High
Bedrock Well # 1	9/17/01	9	2	1
Bedrock Well # 4	9/17/01	10	1	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