Finished Water Quality Report

Cary/Apex Water Treatment Facility
Finished Water Quality Report For 2008

We are pleased to present to you this year's Annual Finished Water Quality Report. This report is a snapshot of last year’s water quality. It is our constant goal to provide you with a safe and dependable supply of drinking water. If you have any questions regarding this report, please contact Kelvin Creech, Manager of the Cary/Apex Water Treatment Facility or Penny Rosser, Chemist at (919) 362-5502.

In order to ensure that tap water is safe to drink, EPA prescribes regulations which limit the amount of certain contaminants in water provided by public water systems. Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. To obtain more information about contaminants and potential health effects, call the Environmental Protection Agency's Safe Drinking Water Hotline (800-426-4791).

Lead and Copper

Contaminant (units)

Sample Date

Your

Water

# of sites found above the AL

MCLG

MCL

Likely Source of Contamination

Copper (ppm)

(90^th percentile)

2006

0.138

1.3

AL=1.3

Corrosion of household plumbing systems; erosion of natural deposits; leaching from wood preservatives

Lead (ppb)

(90^th percentile)

2006

< 3

AL=15

Corrosion of household plumbing systems, erosion of natural deposits

Nitrate and Nitrite

Contaminant (units)

MCL Violation

Y/N

Your

Water

Range

Low / High

MCLG

MCL

Likely Source of Contamination

Nitrate (as Nitrogen) (ppm)

< 1.0

N/A

Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits

Nitrite (as Nitrogen) (ppm)

< 0.01

N/A

Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits

Asbestos

Contaminant (units)

Sample Date

MCL Violation

Y/N

Your

Water

Range

Low / High

MCLG

MCL

Likely Source of Contamination

Total Asbestos (MF/L)

2005

< 0.2

N/A

Decay of asbestos cement water mains; erosion of natural deposits

Note: One asbestos sample is required to be taken during the first 3-yr compliance period of each 9-yr compliance cycle beginning in the compliance period starting 1/1/2002 and ending 12/31/2010. The Cary/Apex WTP collected a sample for asbestos analysis in 2005.

Disinfectants and Disinfection Byproducts

Contaminant (units)	MCL/MRDL Violation Y/N	Your Water (AVG)	Range Low / High	MCLG	MCL	Likely Source of Contamination
TTHM (ppb) [Total Trihalomethanes]	N	71	49 – 85	N/A	80	By-product of drinking water chlorination
HAA5 (ppb) [Total Haloacetic Acids]	N	25	19 – 43	N/A	60	By-product of drinking water disinfection
Bromate (ppb)	N	< 5	N/A	0	10	By-product of drinking water disinfection
Chloramines (ppm)	N	2.68	1.36 – 3.99	MRDLG = 4	MRDL = 4	Water additive used to control microbes
Chlorine, Free (ppm)	N	0.20	0.07 – 0.91	MRDLG = 4	MRDL = 4	Water additive used to control microbes
Chlorine, Total (ppm)	N	2.88	1.46 – 4.90	MRDLG = 4	MRDL = 4	Water additive used to control microbes
Total Organic Carbon (ppm)	N	3.27	2.60 – 3.60	N/A	TT	Naturally present in the environment

Note: Compliance with the MCLs for TTHMs, HAA5s, Bromate, Chloramines, and Free Chlorine are based on the running annual average (RAA) shown in the “Your Water” column.

2008 Finished Water Quality Report - page 2

Turbidity (Combined Filter Effluent Turbidity Values)

Contaminant (units)

MCL Violation

Y/N

Your

Water

MCLG

MCL

Range

Low / High

Likely Source of Contamination

Turbidity (NTU)

0.06

N/A

TT = 1 NTU

0.03 – 0.18

Soil runoff

Note: Compliance with the MCL for turbidity is based on the combined filter effluent turbidity values, not the finished water turbidity values.

Radiologicals

Contaminant (units)	Sample Date	MCL Violation Y/N	Your Water	MCLG	MCL	Likely Source of Contamination
Alpha emitters (pCi/L)	2008	N	< 3	0	15	Erosion of natural deposits
Beta / photon emitters (pCi/L)	2008	N	< 4	0	50	Decay of natural and man-made deposits
Radium 226 (pCi/L)	2008	N	< 1	0	3	Erosion of natural deposits
Radium 228 (pCi/L)	2008	N	< 1	0	2	Erosion of natural deposits
Uranium (pCi/L)	2008	N	< 0.67	0	20.1	Erosion of natural deposits

Microbiologicals

Contaminant (units)	MCL Violation Y/N	Your Water	MCLG	MCL	Likely Source of Contamination
Total Coliform Bacteria (presence or absence)	N	2.5 % were positive	0	5 % of monthly samples are positive	Naturally present in the environment
Fecal Coliform or E. coli (presence or absence)	N	0	0	0 (Note: The MCL is exceeded if a routine sample and repeat sample are total coliform positive, and one is also fecal coliform or E. coli positive)	Human and animal fecal waste
Cryptosporidium (oocysts/L)	N	ND	0	TT = 99 % removal	Human and animal fecal waste
Giardia lamblia (cysts/L)	N	ND	0	TT = 99 % removal/inactivation	Human and animal fecal waste

Trihalomethanes (THMs)

Contaminant (units)	Sample Date	MCL Violation Y/N	Your Water (AVG)	Range Low / High	Likely Source of Contamination
Chloroform (ppb)	2008	N	22.8	16 – 29	By-product of drinking water chlorination
Bromodichloromethane (ppb)	2008	N	25.8	17 – 31	By-product of drinking water chlorination
Bromoform (ppb)	2008	N	3.8	2.3 – 6.0	By-product of drinking water chlorination
Chlorodibromomethane (ppb)	2008	N	21.6	14 – 28	By-product of drinking water chlorination

Note: Compliance with the MCLs for Disinfection By-Products is based on the running annual average shown in the “Your Water” column.

Haloacetic Acids (HAAs)

Contaminant (units)	Sample Date	MCL Violation Y/N	Your Water (AVG)	Range Low / High	Likely Source of Contamination
Trichloroacetic Acid (ppb)	2008	N	7.0	4.1 – 12	By-product of drinking water chlorination
Dichloroacetic Acid (ppb)	2008	N	11.8	5.1 – 24	By-product of drinking water chlorination
Monochloroacetic Acid (ppb)	2008	N	2.5	< 2 – 7.9	By-product of drinking water chlorination
Monobromoacetic Acid (ppb)	2008	N	1.7	< 1 – 5.1	By-product of drinking water chlorination
Dibromoacetic Acid (ppb)	2008	N	5.8	3.5 – 7.7	By-product of drinking water chlorination

Note: Compliance with the MCLs for Disinfection By-Products is based on the running annual average shown in the “Your Water” column.

2008 Finished Water Quality Report - page 3

Regulated Inorganics

Contaminant (units)	Sample Date	MCL Violation Y/N	Your Water	Range Low / High	MCLG	MCL	Likely Source of Contamination
Antimony (ppb)	2008	N	< 3	N/A	6	6	Discharge from petroleum refineries; fire retardants; ceramics; electronics; solder
Arsenic (ppb)	2008	N	< 5	N/A	0	10	Erosion of natural deposits; runoff from orchards; runoff from glass and electronics production wastes
Barium (ppm)	2008	N	< 0.4	N/A	2	2	Discharge of drilling wastes; discharge from metal refineries; erosion of natural deposits
Beryllium (ppb)	2008	N	< 2	N/A	4	4	Discharge from metal refineries and coal-burning factories; discharge from electrical, aerospace, and defense industries
Cadmium (ppb)	2008	N	< 1	N/A	5	5	Corrosion of galvanized pipes; erosion of natural deposits; discharge from metal refineries; runoff from waste batteries and paints
Chromium (ppb)	2008	N	< 20	N/A	100	100	Discharge from steel and pulp mills; erosion of natural deposits
Cyanide, Total (ppb)	2008	N	< 50	N/A	200	200	Discharge from steel/metal factories; discharge from plastic and fertilizer factories
Fluoride (ppm)	2008	N	1.00	< 0.10 – 1.28	4	4	Erosion of natural deposits; water additive which promotes strong teeth; discharge from fertilizer and aluminum factories
Mercury (inorganic) (ppb)	2008	N	< 0.4	N/A	2	2	Erosion of natural deposits; discharge from refineries and factories; runoff from landfills; runoff from cropland
Selenium (ppb)	2008	N	< 10	N/A	50	50	Discharge from petroleum and metal refineries; erosion of natural deposits; discharge from mines
Thallium (ppb)	2008	N	< 1	N/A	0.5	2	Leaching from ore-processing sites; discharge from electronics, glass, and drug factories

Water Quality Characteristics

Contaminant (units)	Sample Date	Your Water (AVG)	Range Low / High	Secondary MCL
Alkalinity, Total, as CaCO₃ (ppm)	2008	43.1	31.0 – 52.5	N/A
Aluminum (ppb)	2008	89.3	< 50 – 366	200
Ammonia, Free (ppm)	2008	0.28	< 0.20 – 0.44	N/A
Ammonia, Total (ppm)	2008	0.98	< 0.20 – 1.45	N/A
Calcium (ppm)	2008	9.17	6.42 – 14.4	N/A
Carbon Dioxide (ppm)	2008	1.67	< 0.01 – 6.82	N/A
Chloride (ppm)	2008	24.4	18.7 – 28.5	250
Color (CU)	2008	1.9	1 – 7	15
Conductivity (uS/cm)	2008	265	225 – 299	N/A
Hardness, Total, as CaCO₃ (ppm)	2008	35.5	26.7 – 49.0	Classified as “moderately soft”
Hardness, Total, as CaCO₃ (grains per gallon)	2008	2.08	1.56 – 2.87	Classified as “moderately soft”
Iron (ppm)	2008	0.049	< 0.05 – 0.105	0.3
Magnesium (ppm)	2008	3.06	2.37 – 3.59	N/A
Manganese (ppm)	2008	0.018	< 0.01 – 0.034	0.05

2008 Finished Water Quality Report - page 4

Water Quality Characteristics (continued)

Contaminant (units)	Sample Date	Your Water (AVG)	Range Low / High	Secondary MCL
Nickel (ppm)	2008	< 0.10	N/A	N/A
Odor (TON)	2008	1.57	1.00 – 10.5	3
Ortho-Phosphate (ppm)	2008	0.83	0.63 – 1.24	N/A
pH (SU)	2008	7.68	7.05 – 8.51	6.5 to 8.5
Silica (ppm)	2004	3.44	< 1.00 – 7.16	N/A
Sodium (ppm)	2008	31.8	18.7 – 43.4	N/A
Sulfate (ppm)	2008	35	N/A	250
Total Dissolved Solids (ppm)	2008	128	91 – 146	500
Total Phosphorous (ppm)	2008	0.27	0.21 – 0.40	N/A
Zinc (ppm)	2006	< 0.005	N/A	5

Note: The most recent sample analyzed for silica was in 2004. The most recent sample analyzed for zinc was in 2006. These parameters are not part of our required compliance monitoring.

Synthetic Organic Chemicals (SOCs) Including Pesticides and Herbicides

(NOTE: All results are below detection limit)

Contaminant (units)	Sample Date	MCL Violation Y/N	Your Water	Range Low / High	MCLG	MCL	Likely Source of Contamination
2,4-D (ppb)	2007	N	< 0.1	N/A	70	70	Runoff from herbicide used on row crops
2,4,5-TP (Silvex) (ppb)	2007	N	< 0.2	N/A	50	50	Residue of banned herbicide
Alachlor (ppb)	2007	N	< 0.2	N/A	0	2	Runoff from herbicide used on row crops
Atrazine (ppb)	2007	N	< 0.1	N/A	3	3	Runoff from herbicide used on row crops
Benzo(a)pyrene (PAH) (ppt)	2007	N	< 20	N/A	0	200	Leaching from linings of water storage tanks and distribution lines
Carbofuran (ppb)	2007	N	< 0.9	N/A	40	40	Leaching of soil fumigant used on rice and alfalfa
Chlordane (ppb)	2007	N	< 0.2	N/A	0	2	Residue of banned termiticide
Dalapon (ppb)	2007	N	< 1	N/A	200	200	Runoff from herbicide used on rights of way
Di(2-ethylhexyl)adipate (ppb)	2007	N	< 0.6	N/A	400	400	Discharge from chemical factories
Di(2-ethylhexyl)phthalate (ppb)	2007	N	< 1.32	N/A	0	6	Discharge from rubber and chemical factories
DBCP (ppt) [Dibromochloropropane]	2007	N	< 20	N/A	0	200	Runoff/leaching from soil fumigant used on soybeans, cotton, pineapples, and orchards
Dinoseb (ppb)	2007	N	< 0.2	N/A	7	7	Runoff from herbicide used on soybeans and vegetables
Endrin (ppb)	2007	N	< 0.01	N/A	2	2	Residue of banned insecticide
EDB (ppt) [Ethylenedibromide]	2007	N	< 10	N/A	0	50	Discharge from petroleum refineries
Heptachlor (ppt)	2007	N	< 40	N/A	0	400	Residue of banned pesticide
Heptachlor epoxide (ppt)	2007	N	< 20	N/A	0	200	Breakdown of heptachlor
Hexachlorobenzene (ppb)	2007	N	< 0.1	N/A	0	1	Discharge from metal refineries and agricultural chemical factories

2008 Finished Water Quality Report - page 5

Synthetic Organic Chemicals (SOCs) Including Pesticides and Herbicides (continued)

(NOTE: All results are below detection limit)

Contaminant (units)	Sample Date	MCL Violation Y/N	Your Water	Range Low / High	MCLG	MCL	Likely Source of Contamination
Hexachlorocyclopentadiene (ppb)	2007	N	< 0.1	N/A	50	50	Discharge from chemical factories
Lindane (ppt)	2007	N	< 20	N/A	200	200	Runoff/leaching from insecticide used on cattle, lumber, gardens
Methoxychlor (ppb)	2007	N	< 0.1	N/A	40	40	Runoff/leaching from insecticide used on fruits, vegetables, alfalfa, livestock
Oxamyl(vydate) (ppb)	2007	N	< 2	N/A	200	200	Runoff/leaching from insecticide used on apples, potatoes and tomatoes
PCBs (ppt) [Polychlorinated biphenyls]	2007	N	< 100	N/A	0	500	Runoff from landfills; discharge of waste chemicals
Pentachlorophenol (ppb)	2007	N	< 0.04	N/A	0	1	Discharge from wood preserving factories
Picloram (ppb)	2007	N	< 0.1	N/A	500	500	Herbicide runoff
Simazine (ppb)	2007	N	< 0.07	N/A	4	4	Herbicide runoff
Toxaphene (ppb)	2007	N	< 1	N/A	0	3	Runoff/leaching from insecticide used on cotton and cattle

Note: The most recent sample analyzed for Regulated SOCs was in 2007.

Unregulated SOCs Including Pesticides and Herbicides

(NOTE: All results are below detection limit)

Contaminant (units)	Sample Date	Your Water	Range Low / High
Aldicarb (ppb)	2007	< 0.5	N/A
Aldicarb Sulfone (ppb)	2007	< 0.8	N/A
Aldicarb Sulfoxide (ppb)	2007	< 0.5	N/A
Aldrin (ppb)	2007	< 0.2	N/A
Butachlor (ppb)	2007	< 8	N/A
Carbaryl (ppb)	2007	< 4	N/A
Dicamba (ppb)	2007	< 1	N/A
Dieldrin (ppb)	2007	< 0.2	N/A
3-Hydroxycarbofuran (ppb)	2007	< 4	N/A
Methomyl (ppb)	2007	< 4	N/A
Metolachlor (ppb)	2007	< 0.8	N/A
Metribuzin (ppb)	2007	< 0.8	N/A
Propachlor (ppb)	2007	< 6	N/A

Note: The most recent sample analyzed for Unregulated SOCs was in 2007.

Volatile Organic Chemicals (VOCs)

(NOTE: All results are below detection limit)

Contaminant (units)	Sample Date	MCL Violation Y/N	Your Water	Range Low / High	MCLG	MCL	Likely Source of Contamination
Benzene (ppb)	2008	N	< 0.5	N/A	0	5	Discharge from factories; leaching from gas storage tanks and landfills
Carbon tetrachloride (ppb)	2008	N	< 0.5	N/A	0	5	Discharge from chemical plants and other industrial activities
Chlorobenzene (ppb)	2008	N	< 0.5	N/A	100	100	Discharge from chemical and agricultural chemical factories

2008 Finished Water Quality Report – page 6

Volatile Organic Chemicals (VOCs)

(NOTE: All results are below detection limit)

Contaminant (units)	Sample Date	MCL Violation Y/N	Your Water	Range Low / High	MCLG	MCL	Likely Source of Contamination
1,2-Dichlorobenzene (ppb)	2008	N	< 0.5	N/A	600	600	Discharge from industrial chemical factories
1,4-Dichlorobenzene (ppb)	2008	N	< 0.5	N/A	75	75	Discharge from industrial chemical factories
1,2 – Dichloroethane (ppb)	2008	N	< 0.5	N/A	0	5	Discharge from industrial chemical factories
1,1 – Dichloroethene (ppb)	2008	N	< 0.5	N/A	7	7	Discharge from industrial chemical factories
cis-1,2-Dichloroethene (ppb)	2008	N	< 0.5	N/A	70	70	Discharge from industrial chemical factories
trans-1,2-Dichloroethene (ppb)	2008	N	< 0.5	N/A	100	100	Discharge from industrial chemical factories
1,2-Dichloropropane (ppb)	2008	N	< 0.5	N/A	0	5	Discharge from industrial chemical factories
Ethylbenzene (ppb)	2008	N	< 0.5	N/A	700	700	Discharge from petroleum refineries
Methylene chloride (ppb) also know as Dichloromethane	2008	N	< 0.5	N/A	0	5	Discharge from pharmaceutical and chemical factories
Styrene (ppb)	2008	N	< 0.5	N/A	100	100	Discharge from rubber and plastic factories; leaching from landfills
Tetrachloroethene (ppb)	2008	N	< 0.5	N/A	0	5	Discharge from factories and dry cleaners
1,2,4 –Trichlorobenzene (ppb)	2008	N	< 0.5	N/A	70	70	Discharge from textile-finishing factories
1,1,1 – Trichloroethane (ppb)	2008	N	< 0.5	N/A	200	200	Discharge from metal degreasing sites and other factories
1,1,2 –Trichloroethane (ppb)	2008	N	< 0.5	N/A	3	5	Discharge from industrial chemical factories
Trichloroethene (ppb)	2008	N	< 0.5	N/A	0	5	Discharge from metal degreasing sites and other factories
Toluene (ppm)	2008	N	< 0.0005	N/A	1	1	Discharge from petroleum factories
Vinyl chloride (ppb)	2008	N	< 0.5	N/A	0	2	Leaching from PVC piping; discharge from plastics factories
Xylenes, Total (ppm)	2008	N	< 0.0005	N/A	10	10	Discharge from petroleum factories; discharge from chemical factories

Unregulated VOCs

(NOTE: All results are below detection limit)

Contaminant (units)	Sample Date	Your Water	Range Low / High
Bromobenzene (ppb)	2008	< 0.5	N/A
Bromochloromethane (ppb)	2008	< 0.5	N/A
Bromomethane (ppb)	2008	< 0.5	N/A
n-Butylbenzene (ppb)	2008	< 0.5	N/A
sec-Butylbenzene (ppb)	2008	< 0.5	N/A
tert-Butylbenzene (ppb)	2008	< 0.5	N/A
Chloroethane (ppb)	2008	< 0.5	N/A
Chloromethane (ppb)	2008	< 0.5	N/A
2-Chlorotoluene (ppb)	2008	< 0.5	N/A
4-Chlorotoluene (ppb)	2008	< 0.5	N/A

2008 Finished Water Quality Report - page 7

Unregulated VOCs (continued)

(NOTE: All results are below detection limit)

Contaminant (units)	Sample Date	Your Water	Range Low / High
Dibromomethane (ppb)	2008	< 0.5	N/A
1,3-Dichlorobenzene (ppb) also know as meta-Dichlorobenzene	2008	< 0.5	N/A
Dichlorodifluoromethane (ppb)	2008	< 0.5	N/A
1,1-Dichloroethane (ppb)	2008	< 0.5	N/A
1,3-Dichloropropane (ppb)	2008	< 0.5	N/A
2,2-Dichloropropane (ppb)	2008	< 0.5	N/A
1,1-Dichloropropene (ppb)	2008	< 0.5	N/A
1,3-Dichloropropene (ppb)	2008	< 0.5	N/A
Hexachlorobutadiene (ppb)	2008	< 0.5	N/A
Isopropylbenzene (ppb)	2008	< 0.5	N/A
4-Isopropyltoluene (ppb)	2008	< 0.5	N/A
Naphthalene (ppb)	2008	< 0.5	N/A
n-Propylbenzene (ppb)	2008	< 0.5	N/A
1,1,1,2-Tetrachloroethane (ppb)	2008	< 0.5	N/A
1,1,2,2-Tetrachloroethane (ppb)	2008	< 0.5	N/A
1,2,3-Trichlorobenzene (ppb)	2008	< 0.5	N/A
1,2,3-Trichloropropane (ppb)	2008	< 0.5	N/A
Trichlorofluoromethane also know as Fluorotrichloromethane	2008	< 0.5	N/A
1,2,4-Trimethylbenzene (ppb)	2008	< 0.5	N/A
1,3,5-Trimethylbenzene (ppb)	2008	< 0.5	N/A

Unregulated UCMR contaminants

(Note: all results are below the method reporting limit for this analysis)

Contaminant (units)	Sample Date	Your Water (AVG)	Range Low / High	MRL
Perchlorate (ppb)	2002	< 4	N/A	4
DCPA Acid Metabolites (ppb)	2002	< 1	N/A	1
MTBE (ppb)	2002	< 5	N/A	5
Nitrobenzene (ppb)	2002	< 10	N/A	10
Acetochlor (ppb)	2002	< 2	N/A	2
2,4 – Dinitrotoluene (ppb)	2002	< 2	N/A	2
2,6 – Dinitrotoluene (ppb)	2002	< 2	N/A	2
4,4 – DDE (ppb)	2002	< 0.8	N/A	0.8
EPTC (ppb)	2002	< 1	N/A	1
Molinate (ppb)	2002	< 0.9	N/A	0.9
Terbacil (ppb)	2002	< 2	N/A	2

Note: The monitoring requirement for these unregulated UCMR contaminants has been met.

No further testing for these contaminants is required at this time.

2008 Finished Water Quality Report - page 8

Treatment Process Information

The treatment process information contained in the following table does not represent what is in the Finished Water. The dosages listed for each chemical represents a range of concentrations for that chemical that may be used at the Water Plant during the water treatment process.

Chemical (units)	Typical Dosage Range	Purpose of Treatment
Ozone (ppm)	0.0 – 7.5	Oxidant
Aluminum Sulfate (ppm)	40 – 65	Coagulant
Polymer (ppm)	0.13 – 0.35	Coagulant aid
Sodium Hydroxide (ppm)	10 – 28	pH control
Carbon (ppm)	4 – 21	Taste and odor control and organics removal
Polymer (ppm)	0.08 – 0.24	Filtration aid
Orthophosphate	2 – 3	Corrosion control
Hydrofluorosilicic Acid (ppm)	0 – 1.05	Fluoride additive
Chlorine (ppm)	3.2 – 13.7	Disinfectant
Ammonia (ppm) *No ammonia is fed during March of each year	0 .98– 1.68	Disinfectant when used in conjunction with chlorine to form chloramines

Important Drinking Water Definitions:

Not-Applicable (N/A) – Information not applicable or not required.

Non-Detects (ND) - the contaminant is not present at the level of detection set for the particular method used.

Method Reporting Limit (MRL) - the lowest reportable concentration set for the particular method used.

Action Level (AL) - The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow.

Treatment Technique (TT) - A treatment technique is a required process intended to reduce the level of a contaminant in drinking water.

Maximum Contaminant Level Goal (MCLG) - The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety.

Maximum Contaminant Level (MCL) - The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology.

Extra Note: MCLs are set at very stringent levels. To understand the possible health effects described for many regulated constituents, a person would have to drink 2 liters of water every day at the MCL level for a lifetime to have a one-in-a-million chance of having the described health effect.

Maximum Residual Disinfection Level Goal (MRDLG) – The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.

Maximum Residual Disinfection Level (MRDL) – The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.

Million Fibers per Liter (MF/L) - is a measure of the presence of asbestos fibers that are longer than 10 micrometers.

Nephelometric Turbidity Unit (NTU) - is a measure of the clarity or turbidity of water.

Microsiemens per centimeter (uS/cm) – is a measure of the conductivity of water.

Parts per million (ppm) or Milligrams per liter (mg/L) - one part substance per million parts water.

Parts per billion (ppb) or Micrograms per liter (ug/L) - one part substance per billion parts water.

Parts per trillion (ppt) or Nanograms per liter (nanograms/L) - one part substance per trillion parts water.

Picocuries per liter (pCi/L) – is a measure of the radioactivity in water.

Running Annual Average (RAA) – compliance calculations based on a running annual average of reported values.

Standard Units (SU) – is a measure of the pH of water.

Threshold Odor Number (TON) – is a measure of the odor of water.

Your Water – is the annual average value, not the maximum value, for the parameter listed. EPA requires that maximum amounts detected be reported in the Annual Water Quality Report (CCR).