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2023 Water Quality Report

Water-Quality-Web

Water Supply ID # NY2704518

The City of Rochester Water Bureau is pleased to present your 2023 Water Quality Report. This report includes water quality information for the 2022 calendar year. The US Environmental Protection Agency (EPA) requires all water utilities to produce and distribute water quality reports on an annual basis. In 2023, the City met or exceeded all of the drinking water standards set by the EPA and the New York State Department of Health (NYSDOH).

 Read the 2023 Water Quality Report below, or download the report, or download the report en Español.

For additional data, download the Supplemental Information

The City of Rochester Water Bureau provides water to 210,000 people and many businesses located within the City of Rochester. In addition, the City partners with the Livingston County Water & Sewer Authority (LCW&SA), Monroe County Water Authority (MCWA) and the Village and Town of Lima to provide water to some of their service areas. The Rochester Water Bureau is committed to providing safe, high quality water and excellent service, while adhering to safe and environmentally friendly practices. The Water Bureau is a part of the Department of Environmental Services, governed by the Mayor of the City of Rochester.

Providing safe and reliable drinking water requires a team of over 120 experienced, dedicated and specially trained employees. Over 40 Water Bureau employees have obtained NYSDOH certification as water system operators. In 2023, the City continued its commitment to water quality through its involvement with the Partnership for Safe Water. The goal of this voluntary American Water Works Association (AWWA) and EPA program is to help water utilities optimize strategies to provide consumers with quality water that exceeds what current regulations require. 2023 marked the 22nd year in a row that the Hemlock Filtration Plant earned the Partnership’s “Director’s Award for Filtration Plants.”

This report provides information about your water system including the source of your drinking water, its treatment and water quality test results. Should you have any questions or require further information, please contact us at (585) 428-6680, ext 1.

Where does my drinking water come from and how is it treated? 

Since 1876, Rochester residents have relied upon Hemlock Lake, with Canadice Lake added in 1919, for their drinking water supply. The City also purchases water from MCWA's Shoremont treatment plant on Lake Ontario. (MCWA water quality information is available at www.MCWA.com.) The Hemlock Water Filtration Plant is a direct filtration plant with a capacity of 48 million gallons per day and employs processes involving pH adjustment, coagulation, filtration, disinfection and flouridation.

Filtration & Disinfection

During coagulation, chemicals are added to untreated water, causing the natural particulates to clump together into larger particles called floc. The floc is removed by filtration and the water is then disinfected with chlorine.

Corrosion Control

The City uses carbon dioxide to adjust water pH as part of its corrosion control strategy. A pH range of 7.7-8.0 is maintained to ensure water in the distribution system is stable and not corrosive to pipes.

Fluoridation  

The City of Rochester is one of the many New York water utilities providing drinking water with a controlled low level of fluoride for consumer dental health protection. According to the U.S. Centers for Disease Control, fluoride is very effective in preventing cavities when present in drinking water at an optimal level of 0.7 mg/L. To ensure optimal dental protection, the State Department of Health requires that we monitor fluoride levels on a daily basis. In 2022 the fluoride levels in your water were within 0.1 mg/L of the CDC’s recommended optimal level 100% of the time.

Water treated at the Hemlock Filtration Plant flows to the city by gravity through three large pipelines. Along the way, water is sold wholesale to water districts in the Town and Village of Lima, LCW&SA and MCWA. The treated water is stored in the City’s three reservoirs—Rush Reservoir, Cobbs Hill Reservoir and Highland Park Reservoir. It is disinfected again as it exits each reservoir and enters a complex grid (over 550 miles) of water mains that distribute the water to city customers. Lake Ontario water from MCWA is pumped into the City distribution system at the Mt. Read Boulevard pump station, near West Ridge Road. Some areas of the city receive either Hemlock Lake or Lake Ontario water—or a mixture of both—depending on the season.

How can I save money on my water bill?

Simple changes in your daily routine can save you money on your water bill and also reduce stress on the environment. Always repair dripping and leaking faucets, toilets and garden hoses. Log on to http://www.dec.ny.gov/lands/5009.html for more conservation tips.

2023 STATISTICS

The City of Rochester has a population about or approximately 210,000, and over 58,700 metered accounts. The base charge for water was $3.96 per 1,000 gallons. The average daily production at the Hemlock Water Filtration Plant was 36.0 million gallons per day (MGD) some of which was sold to wholesale customers. Approximately 23 MGD was delivered to City retail customers and 13 MGD were sold to wholesale customers. 8.2 MGD were considered non-revenue water. The NRW is used for firefighting purposes, water main flushing, or otherwise attributed to distribution system leaks, meter and billing inaccuracies and water illegally obtained. The Water Bureau continues to focus on reducing the amount of NRW.

Questions

For more information about Water Bureau activities, fees and other water-related issues, visit: www.cityofrochester.gov/waterbureau or call (585) 428-7500. You may contact a customer service representative by dialing 311. Call (585) 428-5990 if outside of the city limits. Our offices are at 10 Felix Street, Rochester, NY, 14608. 


Source water assessment summary

To raise awareness about the importance of preventing water pollution, the NYDOH has evaluated the susceptibility of water supplies statewide for potential contamination under the Source Water Assessment Program (SWAP). Through its assessment of the Hemlock/Canadice Lake watershed, SWAP identified several potential sources of contamination, none particularly noteworthy. The City’s extensive testing of these pristine lakes confirms that contamination from human activity is negligible. For more information on SWAP, please call (585) 428-6680, or the Monroe County Department of Public Health at (585) 753-5057.

What types of water system improvement were completed or initiated in 2023?

The City is diligent in reinvesting in your water system through its capital improvement program. In 2023, the Water Bureau spent more than $17 million on system improvements to the Hemlock Filtration Plant, transmission system, distribution system, reservoirs and dams. Some of the program highlights performed in 2023 include, replacing 1,200 feet of water main pipe and appurtenances, cleaning and lining 4.0 miles of water main pipe, structurally lining 0.6 miles of water main pipe. Through various water main projects and efforts by in-house staff 1,673 lead containing water services were replaced in 2023. Improvements continue to the filtration plant automation controls, backup power, and physical and cyber security components. The ongoing program to recalibrate or replace customer’s water meters have led to 80% of our system incorporating radio read meters. Other programs involving inspection of fire hydrants, operating main line valves, water main flushing and sampling and testing of the water were also continued. Cobb’s Hill Reservoir was off line for three months in 2023 for cleaning and routine maintenance.

Information from the EPA

  • 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. More information about contaminants and potential health effects can be obtained by calling the EPA’s Safe Drinking Water Hotline 1-800-426-4791.
  • The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and radioactive material, and can pick up substances resulting from the presence of animals or from human activities. Contaminants that may be present in source water include: microbial contaminants, inorganic contaminants, pesticides and herbicides, organic chemical contaminants and radioactive contaminants.

    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. The Food and Drug Administration (FDA) regulations establish limits for contaminants in bottled water which must provide the same protection for public health.
  • Some people may be more vulnerable to disease-causing microorganisms or pathogens in drinking water than the general population. Immuno-compromised individuals, such as people with cancer undergoing chemotherapy, organ transplant recipients, people with HIV/AIDS or other immune system disorders, some elderly and infants may be particularly at risk from infections. These people should seek advice from their health care providers about their drinking water. EPA/CDC guidelines on appropriate means to lessen the risk of infection by Cryptosporidium, Giardia and other microbial pathogens are available from the Safe Drinking Water Hotline (1-800-426-4791).

Should I be concerned about contaminants?

As NY State regulations require, we routinely test your drinking water for numerous contaminants and we have found no contaminants in our water at levels that raise concern. Some substances such as chlorine and fluoride are added to the water supply for health reasons.

Is there lead in my drinking water?

Lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. The City of Rochester is responsible for providing high quality drinking water and removing lead pipes, but cannot control the variety of materials used in plumbing components in your home. You share the responsibility for protecting yourself and your family from the lead in your home plumbing. You can take responsibility by identifying and removing lead materials within your home plumbing and taking steps to reduce your family’s risk. Before drinking tap water, flush your pipes for several minutes by running your tap, taking a shower, doing laundry or a load of dishes. You can also use a filter certified by an American National Standards Institute accredited certifier to reduce lead in drinking water. If you are concerned about lead in your water and wish to have your water tested, contact The City of Rochester Hemlock Water Quality Lab at (585) 428-6680 Ext 1. 

  1.  Information on: lead in drinking water, testing methods, and steps you can take to minimize exposure is available at epa.gov/safewater/lead.
  2.  Check Available Records: Water service material records are available in the Property Information Application at maps.cityofrochester.gov/propinfo/. Enter address and click “Water” tab or call the Water Dispatch office at (585) 428-7500.
  3. Have Your Water Tested for Free: Contact the Water Bureau’s Laboratory at (585) 428-6680 Ext 1, or by email to: watertest@cityofrochester.gov
  4. Inspect Your Plumbing: To identify sources of lead in your plumbing go to: www.lslrcollaborative.org/identifyingservice- line-material.html. Contact a licensed plumber: call the City’s Bureau of Buildings and Zoning Permit Office at (585) 428-6526 or go to: www.cityofrochester.gov/licensedtrades/.

Steps you can take to reduce lead

  • Use ONLY Cold Water for drinking, cooking and preparing baby formula. Hot water dissolves lead more quickly. 
  • Flush Your Pipes any time water has been unused for more than 4-6 hours. Lead levels are highest when water has been sitting in the pipe. 
  • Periodically Clean Faucet Screens which can accumulate lead and rust particles. 
  • Use a Water Filter - If you have concerns about levels of lead in your water, consider using a water filter that is certified by the NSF International to remove lead. Find out more on filter certification at www.nsf.org

Additional information is available at:

Cryptosporidium and giardia 

Cryptosporidium is a microbial pathogen found in surface water and groundwater under the influence of surface water. Although filtration removes Cryptosporidium, the most commonly used filtration methods cannot guarantee 100 percent removal. 

The Long Term 2 Enhanced Surface Water Treatment Rule (LT2) requires that uncovered finished water storage reservoirs either be covered or have treatment installed to inactivate cryptosporidium. In order to comply with LT2, the City of Rochester entered into a compliance agreement with the Monroe County Department of Health and the New York State Department of Health  in 2012. It was revised and updated in 2022.

The Agreement requires the City to conduct routine Cryptosporidium monitoring (twice monthly) from both Highland and Cobbs Hill reservoirs. During 2023, as part of our routine sampling plan, forty two (42) samples for Cryptosporidium or Giardia oocysts were collected, twenty four at Highland Reservoir and eighteen at Cobbs Hill (Cobbs Hill was off line for three months). No Cryptosporidium or Giardia oocysts were recovered for any samples collected at Cobbs Hill or Highland Reservoir.

Table of detected contaminants

ENTRY POINT - TREATMENT PLANT EFFLUENT 
SUBSTANCEUNITSMCLGMCLHEMLOCK AVERAGE (RANGE)ONTARIO AVERAGE (RANGE)LIKELY SOURCEMEETS EPA STANDARDS
COMBINED RADIUM 226+228 (2019)pCi/L051.11+0.54NDErosion of natural depositsYes
ALKALINITYmg/LNANA7291 (89-92)Naturally OccurringNA
ALUMINUMug/LNA     200847(24-67)Treatment ProcessYes
BARIUMmg/L220.0170.020 (0.018-0.021)Erosion of natural depositsYes
CALCIUMmg/LNANA2634 (32-35)Naturally occurringNA
COPPERmg/L1.31.30.015NDErosion of natural deposits, corrosion of plumbingYes
CHLORIDEmg/L2502503725 (23-26)Natural deposits, road salt, water treatment chemicalsYes
FLUORIDEmg/LNA2.20.68 (0.08-0.77)0.72 (0.20-0.98)Water treatment additive to promote dental healthYes
MAGNESIUMmg/LNANA6.68.6Naturally OccurringNA
NITRATEmg/L10100.08 (0.01-0.14)0.26 (ND-0.50)Fertilizers, erosion of natural deposits, septic tank leachateYes
PERFLUOROOCTANE-SULFONIC ACID (PFOS)
ng/LNA10ND0.6 (ND-2.4)Commercial and Industrial applicationsYes
PERFLUOROBUTANOIC ACID (PFBA)
ng/LNA10ND1.7 (ND-2.5)Commercial and Industrial applicationsNA
PHSUNANA7.8 (7.3-8.2)7.5 (7.2-8.2)Naturally Occurring, treatment processNA
POTASSIUMmg/LNANA1.61.7Naturally OccurringNA
SILICAmg/LNANANA0.50 (0.36-0.67)Naturally OccurringNA
SPECIFIC CONDUCTIVITYUmhos/cmNANA297 (267-346)303 (290-320)Naturally OccurringNA
SODIUMmg/LNANA2015 (14-16)Natural deposits, road salt, water treatment chemicalsNA
SULFATEmg/LNA2502226 (24-27)Naturally OccurringYes
TOTAL DISSOLVED SOLIDSmg/LNANA160173 (160-180)Naturally OccurringNA
TOTAL HARDNESSmg/LNANA92123 (120-130)Naturally OccurringNA
MICROBIOLOGICAL CONTAMINANTS - ENTRY POINT
SUBSTANCE UNITSMCLGMCLAVERAGE (ANNUAL RANGE)LIKELY SOURCE MEETS EPA STANDARDS
Water Clarity Treatment Requirements (TT) - 95% of samples each month must be less than 0.3 NTU. Annual Range and lowest monthly percentage are listed below for entry point. Turbidity is a measure of water clarity and is used to gauge filtration process.
TURBIDITY-ENTRY POINTNTUNA100% < 0.3 NTU
0.05 (<0.03-0.14)
(100%<0.3 NTU) 
Soil RunoffYes
Disinfectant and Disinfectant By-products (DBPs) - Entry Point. Chlorine has a MDRL (Maximum Disinfectant Residual Level) and MDRLG (MDRL Goal) of 4 mg/L rather than an MCL and MCLG.
CHLORINE-ENTRY POINTmg/L440.9 (0.7-1.4)Required Treatment ChemicalYes
UV254Abs/cmNANA0.033Naturally OccurringYes
TOTAL ORGANIC CARBONmg/LNATT2.47Naturally OccurringYes
TOTAL THMSug/LNA8019By-product of chlorinationYes
HALOACETIC ACIDSug/LNA6011By-product of chlorinationYes


 

CITY OF ROCHESTER DISTRIBUTION SYSTEM
Microbiological Contaminants – The distribution system monthly maximum and annual average % positive for total coliform bacteria are listed below. Total Coliform is a group of bacteria used to indicate the general sanitary conditions in a water system. Most species of this group do not present a health concern, but one species, E. coli can be pathogenic. In 1993, the State Health Department granted the City a “biofilm variance,” or exception to the Total Coliform MCL. Biofilm is a layer of bacteria that can be found on almost all surfaces, including the inside wall of water pipes. The variance does not apply to E. coli. Cryptosporidium and Giardia samples are collected from the reservoir effluent prior to chlorination. Sample frequency for cryptosporidium or giardia increases from twice per month to weekly within a given month whenever an oocyst is detected. 
SUBSTANCEUNITSMCLGMCLHIGHEST % POSITIVE (MONTH)LIKELY SOURCEMEETS EPA STANDARDS
TOTAL COLIFORM% Positive0NA3.0 (July)
(0.7% Annual Average)
Naturally OccurringYes
Water Clarity Treatment Requirements (TT) For the distribution system the highest monthly average and range are reported. Turbidity is a measure of water clarity and is used to gauge filtration process.
SUBSTANCE UNITSMCLGMCLAVERAGE (RANGE)LIKELY SOURCEMEETS EPA STANDARDS 
TURBIDITY-DISTRIBUTIONNTUNA5 NTU
0.11 (<0.01- 0.96) 
Soil Runoff, Corrosion of PlumbingYes
Disinfectant and Disinfectant By-products (DBPs) Distribution System – Average (Highest LRAA for Total THMs and Haloacetic Acids) and Range are listed below. Chlorine has a MDRL (Maximum Disinfectant Residual Level) and MDRLG (MDRL Goal) rather than an MCL and MCLG. LRAA=Locational Running Annual Average.
FREE CHLORINEmg/L440.91 (0.25-1.94)Required Treatment ChemicalYes
TOTAL THMSug/LNA8047 (15-76)By-product of chlorinationYes
HALOACETIC ACIDSug/LNA6029 (7-64)By-product of chlorinationYes
Lead and Copper (2023 Survey) –Test results for 90% of distribution system samples must be less than the Action Level (AL). The 90th percentile and the range of results are listed below (90th percentile: 90% of samples were at, or below, the value reported).
SUBSTANCE  UNITS  MCLGMCL90th PERCENTILE RANGE LIKELY SOURCE MEETS EPA STANDARDS
LEADug/L01510 (ND-52.5), (103 samples collected)Corrosion of plumbingYes
COPPERug/L13001300260 (20-430), (103 samples collected) Corrosion of plumbingYes

EPA's Fifth Unregulated Contaminant Monitoring Rule (UCMR5)

Contaminant

Acronym

2023 Sample Events - Unit - ug/L (parts per billion)

SE1 (2/23)

SE2 (5/23)

SE3 (8/23)

SE4 (11/23)

RWW

MCWA

RWW

MCWA

RWW

MCWA

RWW

MCWA

Perfluorobutanoic acid

PFBA

ALL NOT DETECTED

RWW = Rochester Water Works

MCWA = Monroe County Water Authority

Perfluoropenatnoic acid

PFPeA

Perfluorohexanoic acid

PFHxA

Perfluoroheptanoic acid

PFHpA

Perfluorooctanoic acid (Regulated)

PFOA

Perfluorononanoic acid

PFNA

Perfluorodecanoic acid

PFDA

Perfluoroundecanoic acid

PFUnA

Perfluorododecanoic acid

PFDoA

4,8 Dioxa-3H-Perfluorononanoic acid

ADONA

Perfluorobutanesulfonic acid

PFBS

Perfluorohexanesulfonic acid

PFHxS

Perfluoroheptanesulfonic acid

PFHpS

Perfluorooctanesulfonic acid (Regulated)

PFOS

Perfluoropentanesulfonic acid

PFPeS

Hexafluoropropylene Oxide Dimer acid

HFPO-DA

9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid

9Cl-PF3ONS

11-Chloroeicosafluoro-3-oxaundecane-1-1sulfonic acid

11Cl-PF3OUdS

1H,1H,2H,2H-Perfluorohexane sulfonic acid

4:2 FTS

1H,1H,2H,2H-Perfluorooctane sulfonic acid

6:2 FTS

1H,1H,2H,2H-Perfluorodecane sulfonic acid

8:2 FTS

Nonafluoro-3,6-dioxaheptanoic acid

NFDHA

Perfluoro-3-methoxypropanoic acid

PFMPA

Perfluoro-4-methoxybutanoic acid

PFMBA

Perfluoro (2-ethoxyethane) sulfonic acid acid

PFEESA

N-ethylperfluorooctanesulfonamidoacetic acid

NEtFOSAA

N-methylyperfluorooctanesulfonamidacetic acid

NMeFOSAA

Perfluorotetradecanoic acid

PFTA

Perfluorotridecanoic acid

PFTrDA

Lithium

Li

Distribution System Water Quality Parameters: Water Quality Parameter (WQP) samples collected quarterly from 21 representative locations to comply with the lead and copper rule in 2023.
Substance

units

MCLG

MCL

Average (Annual Range)

Likely source

Meets EPA Standards

pH

SU

NA

NA

7.87 (7.55-8.24)

Naturally occurring, Treatment Process

Yes

Free Chlorine  

mg/L

4

4

0.93 (0.10-1.59)

Required Treatment Chemical

Yes

Turbidity -Distribution

NTU

NA

5 NTU

0.08 (0.05-0.34)

Soil Runoff, Corrosion of Plumbing

Yes

Alkalinity

mg/L

NA

NA

72 (47-92)

Naturally occurring

NA

Specific Conductivity

Umhos/cm

NA

NA

302 (293-319)

Naturally Occurring

Yes

Temperature

Deg C

NA

NA

18 (10-24)

Seasonal

NA

Entry Point Water Quality Parameter (WQP) samples collected in 2023 to comply with the lead and copper rule.
Substance

units

MCLG

MCL

Average (Annual Range)

Likely source

Meets EPA Standards

pH

SU

NA

NA

7.82 (7.73-8.03)

Naturally occurring, Treatment Process

Yes

Free Chlorine  

mg/L

4

4

0.98 (0.91-1.30)

Required Treatment Chemical

Yes

Turbidity –Entry Point

NTU

NA

0.3 NTU

0.05 (0.04-0.07)

Soil Runoff, Corrosion of Plumbing

Yes

Alkalinity

mg/L

NA

NA

72 (59-76)

Naturally occurring

NA

Specific Conductivity

Umhos/cm

NA

NA

298 (286-308)

Naturally Occurring

Yes

Temperature

Deg C

NA

NA

18 (7-25)

Seasonal

NA

Note: The following contaminants were tested for but not found in HWTP effluent: Benzene, Bromobenzene, Bromochloromethane, Bromomethane, n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, Carbon tetrachloride, Chlorobenzene, Chloroethane, Chloromethane,2-Chlorotoluene, 4-Chlorotoluene, 1,2-Dibromo-3-chloropropane (DBCP), 1,2-Dibromoethane (EDB), 1,2-Dichlorobenzene, 1,3-Dichlorobenzene, 1,4-Dichlorobenzene, Dichlorodifluoromethane, 1,1-Dichloroethane, 1,2-Dichloroethane, 1,1-Dichloroethylene, cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, Dichloromethane, 1,2-Dichloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, 1,1-Dichloropropylene, cis-1,3-Dichloroproylpene, trans-1,3-Dichloropropylene, Ethyl benzene, Hexachlorobutadiene, Isopropylbenzene, 4-Isopropyltoluene, Methyl-t-butyl ether (MTBE), Naphthalene, n-Propylbenzene, Styrene, 1,1,1,2-Tetrachloroethane, 1,1,2,2-Tetrachloroethane, Tetrachloroethylene, Toluene, 1,2,3-Trichlorobenzene, 1,2,4-Trichlorobenzene, 1,1,1-Trichloroethane, 1,1,2-Trichloroethane, Trichloroethylene, Trichlorofluoromethane, 1,2,3-Trichloropropane, 1,2,4-Trimethylbenzene, 1,3,5-Trimethylbenzene, Vinyl chloride, o-Xylene, m,p-Xylene, Total Xylene, 2,3,7,8- Tetrachlorodibenzo-p-Dioxin, 1,2-Dibromo-3-Chloropropane (DBCP), 1,2-Dibromoethane (EDB), PCB Screen, Chlordane, Toxaphene, 2,4-D, Dacthal, Dalapon, Dicamba, Dinoseb, Pentachlorophenol, Picloram, 2,4,5-TP (Silvex), Alachlor, Aldrin, Atrazine, Benzo(a)pyrene, Gama-BHC (Lindane), Butachlor, Dieldrin, Di(2-ethylhexyl) adipate, Di(2-ethylhexyl) phthalate, Aldicarb, Aldicarb Sulfoxide, Bis(2-Ethylhexyl)phthalate, Endrin, Heptachlor, Heptachlor epoxide, Hexachlorobenzene, Hexachlorocyclopentadiene, Methoxychlor, Metolachlor, Metribuzin, Propachlor, Simazine, Aldicarb,  Aldicarb sulfone, Aldicarb sulfoxide, Carbaryl, Carbofuran, 3-Hydroxycarbofuran, Methomyl, Oxamyl, Glyphosate, Endothall, Diquat, Gross Alpha, Total Uranium, Aluminum, Antimony, Beryllium, Cadmium, Total Cyanide,  Iron, Manganese, Mercury, Nitrite, Selenium, Silver, Zinc, Foaming Agents (MBAS), Asbestos 1,4-Dioxane and Per- and poly-fluoroalkyl substances.

Refer to the Supplemental Report (Downloadable PDF) for a comprehensive list of all detected and undetected contaminants that were tested for in 2023 and/or in prior years. The supplemental report also provides information on health effects associated with all detected contaminants.

Definitions

  • Abs/cm = The unit of measure for UV absorbance: Absorbance per centimeter (abs/cm), referring to how much UV is absorbed at a specific wavelength

  • 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 MCLG as possible.

  • Maximum Residual Disinfectant 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.

  • Maximum Residual Disinfectant 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 contamination.

  • Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water.

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

  • Nephelometric Turbidity Unit (NTU): A measure of the clarity of water. Turbidity in excess of 5 NTU is just noticeable to the average person.

  • Milligrams per liter (mg/l) corresponds to one part of liquid in one million parts of liquid (parts per million - ppm).

  • Micrograms per liter (ug/l) corresponds to one part of liquid in one billion parts of liquid (parts per billion - ppb).

  • NA: Not applicable

  •  Nanograms per liter (ng/L): One part of liquid in 1 trillion parts of liquid (parts per trillion = ppt). 

  • Non-Detects (ND): Laboratory analysis indicates that the constituent is not present.

  • pCi/L= picocurie/L: A unit of measure for radioactivity.

  • Non-Detects (ND): Laboratory analysis indicates that the constituent is not present.

  • Umhos/cm = The unit of measurement for conductivity: Expressed as micromhos (umho/cm).