2007

The source of the Drew Woods water supply is six wells located in the Drew Woods system off Olsen Road near Drew Woods Drive in East Derry, NH.  Treatment consist of chlorination for disinfection, aeration to reduce radon levels, and phosphate addition to sequester iron and manganese. 
DREW WOODS
EPA # 0612150
Inorganic Contaminants Units MCLG MCL Level Detected Range Year Violation Yes/No Typical Source of Contaminant
Arsenic ppb n/a 10 4 n/a 2006 NO Erosion of natural deposits; runoff from orchards; runoff from glass and electronics production wastes.
Barium ppm 2 2 0.016 n/a 2005 NO Discharge of drilling wastes; discharge from metal refineries; erosion of natural deposits.
Radiological Contaminants Units MCLG MCL Average Level Detected Range Year Violation Yes/No Typical Source of Contaminant
Gross Alpha (Compliance) pCi/L 0 15 2.6 1.6 - 3.4 2004 NO Erosion of natural deposits
Combined Radium  pCi/L 0 5 1.48 1.3 - 1.7 2004 NO Erosion of natural deposits
Uranium ppb n/a 30 3.85 2.8 - 4.9 2004 NO Erosion of natural deposits
Inorganic Contaminants Units MCLG AL 90th percentile sample value                      # sites above AL Year Violation Yes/No Typical Source of Contaminant
Lead ppb 0 15 < 5 1 of 10 2006 NO Corrosion of household plumbing system
Copper ppm 1.3 1.3 0.143 0 of 10 2006 NO Corrosion of household plumbing system
Volatile Organic Contaminants Units MCLG MCL Average Level  Detected Range Year Violation Yes/No Typical Source of Contaminant
Total Trihalomethanes (TTHMs) ppb n /a 80 7.1 7.1 2006 NO By-product of drinking water chlorination.
Haloacetic Acids (HAA5) ppb n/a 60 1.3 nd - 2.7 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 0.41 nd to 0.9 2006 NO Water additive used to control microbes
Source Assessment Information
    Summary of Susceptibility Factors
Source Name Date Low Med High Well Location
Bedrock Well # 1  3/18/02 6 5 1 Located 90' northeast of the pump house     
Bedrock Well # 3 3/18/02 6 5 1 Located 120' northeast of the pump house     
Bedrock Well # 4 3/18/02 7 4 1 Located 100' north of the pump house     
Bedrock Well # 5 3/18/02 8 3 1 Located 275' northwest of the pump house     
Bedrock Well # 6 3/18/02 9 2 1 Located 310' northwest of the pump house     
Bedrock Well # 7 3/18/02 8 3 1 Located 437' northwest of the pump house     
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