How can I stay informed? Arizona Department of Environmental Quality (ADEQ) evaluated each water source used by public water systems in As a citizen of Peoria, you can stay informed of what is Arizona. ADEQ looked at the quality of groundwater being happening in the Utilities Department in several ways. These drawn into wells, the watersheds supplying surface water, and include visiting the Departmental website www.peoriaaz.gov, by land use activities occurring near drinking water sources. This attending a free water conservation class, by visiting the information is used to determine the degree to which a public departmental booth at various City events, by attending City drinking water source is protected from, or at risk of, Council meetings or watching Channel 11. These forums contamination. It is also used to assist local communities in provide an opportunity for citizens to learn about various implementing source water protection measures to preserve programs, the decision process of the department and permit you drinking water quality. WaterReport2007 Peoria Water System City of Peoria Utilities Department Si usted quiere esta información en español por favor visita www.peoriaaz.gov/utilities/ o llama al 623-773-7286. Director’s Letter This annual Consumer Confidence Report, or CCR, provides to express your opinions and concerns. You can also email the department directly at utilities@peoriaaz.gov or to speak to a When preparing Peoria’s SWAP, ADEQ evaluated 24 wells. One information on water quality in areas that are serviced by Peoria staff representative please contact 623-773-7286. of these wells was found to have a high risk of contamination due for calendar year 2007. The City of Peoria Utilities Department to its proximity to an old gas station. While contamination is not is committed to providing a sustainable, high-quality, water occurring or even imminent, ADEQ must list the whole Peoria supply. We are committed to distributing water to your tap that is system as having a high risk of contamination. The well in treated, tested, and safe. Free Water Conservation Literature The Peoria Utilities Department question, along with all other city wells, is tested routinely per offers free information booklets federal, state, and county regulations, and no evidence of In our desert environment, water resources and planning and brochures to its citizens contamination has been detected. The full SWAP report for management are critical to our future water supply. An interested in learning more the city can be reviewed at both Peoria Public Libraries and about water resources, the Utilities Department office at 8401 W. Monroe Street. Xeriscape, landscape Learn more about water quality irrigation, and indoor water conservation. Spanish language important aspect of living in the desert is water conservation. We Legend Vistancia Area Central Area Peoria City Limits Map Not to scale Water Treatment Plant Agua Fria River Canal encourage every citizen to use water wisely and adapt to a watersaving lifestyle. Please read on for more information on how we provide you, our valued customer, with a safe and sustainable water supply both now and in the future. The Peoria 2007 Water Report is produced by the Additional water quality information and answers to frequently brochures on Xeriscape The following web sites provide more information and desert lawn care are also about drinking water quality standards in Arizona asked questions are available at the department website at available upon request. If you would and the United States: www.peoriaaz.gov. For more water conservation information like to request a literature packet or Spanish brochures visit United States Environmental Protection Agency, www.conserve.peoriaaz.gov or Office of Groundwater and Drinking Water: call 623-773-7286. www.epa.gov/OGWDW City of Peoria regarding water saving tips, free classes, and rebates visit the Surface water undergoes extensive treatment at either the website www.conserve.peoriaaz.gov. Pyramid Peak or Greenway Water Treatment Plants to meet Sincerely, Utilities Department Water Resources & Conservation Division Source Water Assessment Provide reliable, quality water services to Peoria customers today and tomorrow. Arizona Department of Environmental Quality: www.adeq.state.az.us/environ/water/dw/index.html The Source Water Assessment Program (SWAP) report for 623-773-7286 Peoria is available for review. Based on a mandate set forth in Maricopa County Environmental Services: the 1996 amendments to the Safe Drinking Water Act, the www.maricopa.gov/envsvc/water/drinking.asp Visit us online: www.conserve.peoriaaz.gov drinking water standards. These facilities use conventional and Peoria has invested in four distinct water supplies. Drinking chemical treatment including chlorine dioxide or ozone to water, also called potable water, comes from the Salt River mitigate taste and odor, and minimize disinfection by-products. Project (SRP), the Central Arizona Project (CAP), and groundwater. This redundancy in our drinking water supply Environmental Compliance Division Stephen L. Bontrager, P.E., D.E.E., Director Tested – Over 200 tests are performed by plant operators helps ensure the availability of water. When one drinking water Stephen Bontrager, P.E., D.E.E. each day, and several parameters are monitored continuously supply is experiencing below-normal water levels, the city has Utilities Department Director using state-of-the-art equipment, which notifies staff members of two other supplies it can rely upon to provide drinking water to Phone: 623-773-7286 any deviations from acceptable conditions. Once the water leaves our customers. Reclaimed water, a fourth water supply, offsets E-mail: utilities@peoriaaz.gov the water supply well or water treatment plant, water quality is some uses where drinking quality water is not needed, such as measured within the distribution system to ensure drinking water for irrigation and decorative water features. The information and data contained in this report apply only to those standards are maintained. who receive their water from the City of Peoria. There are several City of Peoria Utilities Department Where your water supply comes from private water companies that serve residents in certain areas of the Safe – Drinking water safety is the primary concern of the city. If you receive your water from the Sunrise, New River, Rose Utilities Department. Safety is achieved by coordinating Valley, or Arizona American water companies, you should contact technology and qualified staff members to monitor production your water supplier directly for water data that affects you: systems, sample the distribution system, and evaluate 2007 Water Supply opportunities to continually enhance the program while PRSRT STD ECRWSS U.S. POSTAGE PAID PEORIA, AZ PERMIT No. 44 8401 W. Monroe St. Peoria, AZ 85345 2007 Water Report Sunrise Water Company: 623-972-6133 New River Water Company: 623-561-1848 Rose Valley Water Company: 800-850-4482 Arizona American: 800-383-0834 minimizing cost to our customers. Water is treated and tested at groundwater wells and treatment plants and then monitored to ensure it remains safe on the way to your tap. Numerous chemical and biological analyses are www.peoriaaz.gov/utilities Treated,Tested, and Safe: Exceptional Service in Every Drop ©2008 All Rights Reserved 4/08 conducted daily. A wide variety of compounds are monitored and tested for in your drinking water, in accordance with federal and state laws and local water quality guidelines. In 2007, SRP delivered approximately 36% of Peoria’s water The City of Peoria Utilities Department is committed to Postal Customer providing a safe, healthy, assured water supply to the community The Peoria Utilities Department supports a committee of the supply from its reservoirs on the Salt and Verde Rivers through at a reasonable cost. City of Peoria drinking water is “treated, Arizona Water and Pollution Control Association called Tap the Arizona Canal. Approximately 30% of Peoria’s water was tested, and safe.” This is a phrase commonly used, but what Into Quality (TIQ). TIQ provides educational materials to supplied from the Colorado River via the 336-mile long CAP does it mean to you as a consumer? schools and the public on tap water safety and quality. For more canal, which starts in Lake Havasu. Nearly 28% of the city’s information on TIQ please visit www.tapintoquality.com. water supply came from groundwater. This groundwater use is Treated – Since the city’s drinking water originates from offset by the recharge of renewable supplies of water (e.g. SRP groundwater and surface water, two different treatment methods and CAP). The remaining 6% was supplied as reclaimed water are used. Water from wells is chlorinated prior to delivery. used only for irrigation of large landscaped areas and filling of decorative water features. Water Quality Data Definitions and Abbreviations The data presented on the following pages provide a detailed microbiological and chemical analysis of Peoria’s water supply for calendar year 2007, during which Peoria supplied water through three different systems. Data from the Central Area and the Vistancia Area water systems are reported separately. Peoria water customers west of the Agua Fria River and north of the Loop 303/Happy Valley Road alignment received water from the Vistancia Area system; most other Peoria water customers received water from the Central Area system. Should you have other water quality questions, contact us at utilities@peoriaaz.gov or 623-773-7286. AL: µg/L: micrograms per liter: a unit of measurement equal to ppb (parts per billion) mg/L: milligrams per liter: a unit of measurement equal to ppm (parts per million) MRDL: Maximum Residual Disinfectant Level : 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. MCL: Maximum Contaminant Level: 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. MCLG: Maximum Contaminant Level Goal: 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. Action level: The concentration of a contaminant that, if exceeded, triggers treatment or other requirements that a water system must follow. C/100ml: colonies per 100 milliliters Gr/gal: Grains Per Gallon: measure of water hardness EPA: United States Environmental Protection Agency Central Area Water System Water Quality Data Organics Aesthetics Analyte Units Alkalinity mg/L Calcium mg/L Hardness Gr/gal Range Average 101-213 157 Greenway Surface Water Concentrations Pyramid Peak Surface Water Concentrations Range Average Range 145 NR 119-194 EPA Limit MCL EPA Limit MCLG NA Sample Date NA 2007 Naturally present 13-51 36 60* 60* NR NR NA NA 2007 Erosion of natural deposits 3.8-15.1 9.5 15* 15* NR NR NA NA 2007 Naturally present mg/L 8-32 18 26* 26* NR NR NA NA 2007 Erosion of natural deposits Manganese mg/L ND ND ND* ND* NR NR NA 0.05 2007 Naturally present 7.3-8.8 7.9 7.7-8.0 7.9 NR NR NA NA 2007 NA 543* 543* NR NR NA NA 2007 Naturally present pH Total Dissolved Solids mg/L 201-463 297.0 Sulfate mg/L 26-48 35 150* 150* NR NR NA 250 2007 Naturally present Sodium mg/L 28-72 40 129* 129* NR NR NA NA 2007 Naturally present Dibromochloropropane ppt (DBCP) Range Highest ND-10 10 Dinoseb µg/L ND-0.3 Dibromochloropropane (DBCP) Dinoseb ND 0.3 Copper and Lead Sample Date Number of sites above AL Analyte Copper mg/L 0.29 1.3 1.3 2007 Zero Erosion of natural deposits, Home plumbing systems. Lead µg/L 4 15 0 2007 Zero Erosion of natural deposits, Home plumbing systems. ND ND Average ND ND NR EPA Limit Sample MCLG Date 200 NR 0 7 7 Possible Sources Runoff from herbicides used on soybeans and vegetables. Some people who drink water containing Dinoseb well in excess of the MCL over many years could experience reproductive difficulties. Analyte Units Gross Alpha pCi/L Gross Beta mrem Radium 226 pCi/L Combined Radium Greenway Surface Water Concentrations Highest Average Range ND-3.7 0.93* Pyramid Peak Surface Water Concentrations HighestAvg. Range EPA Limit MCL EPA Limit MCLG Sample Date Possible Sources Erosion of natural deposits Highest 1.2 NR NR 15 0 2007 ND ND NR NR 4 0 2007 ND-0.4 0.07* ND-1 1 NR NR NA NA 2007 Erosion of natural deposits pCi/L ND-0.4 0.07* ND-1 1 NR NR 5 0 2007 Erosion of natural deposits Uranium µg/L ND-5.7 2.47* 1.5-3.7 3.7 NR NR 30 0 2007 Erosion of natural deposits Radon pCi/L ND-515 273* ND-358 358 NR NR NA NA 2007 Erosion of natural deposits ND-4 0.31* Decay of natural and man-made deposits. Disinfection Byproducts Overall Water System Concentrations Analyte Units Highest Average Range Greenway Surface Water Concentrations Pyramid Peak Surface Water Concentrations Range Highest Avg. Range Highest NR EPA Limit MCLG Sample Date NR 10 0 2007 By-product of drinking water ozonation NR NR TT NA 2007 Naturally present in the environment Possible Sources Bromate* µg/L NR NR ND-11* Total Organic mg/L NR NR 11-55% 42%(15% required) Total µg/L Trihalomethanes ND-61 45* NR NR NR NR 80* NA 2007 By-product of drinking water chlorination Total Haloacetic µg/L Acids ND-21 12* NR NR NR NR 60* NA 2007 By-product of drinking water chlorination Carbon % removal 0.72* EPA Limit MCL * A single analysis above the MCL is not a violation. Compliance is determined on a running annual average. Radon is a radioactive gas that you cannot see, taste, or smell. It is found throughout the United States. Radon can move up through the ground and into a home through cracks and holes in the foundation. Radon can build up to high levels in all types of homes. Radon can also get into indoor air when released from tap water from showering, washing dishes, and other household activities. Compared to radon entering the home through soil, radon entering the home through tap water will in most cases be a small source of radon in indoor air. Radon is a known human carcinogen. Breathing air containing radon can lead to lung cancer. Drinking water containing radon may also cause increased risk of stomach cancer. If you are concerned about radon in your home, test the air in your home. Testing is inexpensive and easy. For additional information, call your state radon program or call EPA’s Radon Hotline (800-SOS-RADON). Analyte Greenway Surface Water Concentrations Pyramid Peak Surface Water Concentrations Units Range Highest Range Range Arsenic* µg/L ND-12* Barium mg/L 0.01- 0.08 Highest EPA EPA Limit Limit MCL MCLG Greenway Pyramid Peak Sample Date The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, Possible Sources Highest 5* ND-6 4* 1.1 1.1 10 0 2007 Erosion of natural deposits 0.08 0.08 0.08 150 150 2 2 2007 Erosion of natural deposits Cadmium µg/L ND ND 0.4 0.4 ND ND 5 5 2007 Erosion of natural deposits Chromium µg/L ND-20 20 ND ND ND ND 100 100 2007 Erosion of natural deposits Fluoride mg/L ND-0.94 0.94 0.6-0.72 0.72 0.35 0.35 4 NA 2007 Erosion of natural deposits Nitrate mg/L ND-9.7 9.7 ND-2.6 2.6 ND ND 10 10 2007 Fertilizer runoff, erosion of natural deposits Nitrate: The City of Peoria has five wells with nitrate concentrations above 5.0 mg/L but less than the MCL of 10 mg/L. Nitrate in drinking water at levels above 10 mg/L is a health risk for infants of less than six months of age. High nitrate levels in drinking water can cause blue baby syndrome. Nitrate levels may rise quickly for short periods of time because of rainfall or agricultural activity. If you are caring for an infant, ask advice from your health care provider. Arsenic Information: The City of Peoria obtained 28% of its water from groundwater wells during 2007. Some of these wells contain arsenic above a new MCL of 10 µg/L that was effective January 23, 2006. Peoria has evaluated its arsenic treatment options and developed a compliance strategy. Due to the variation of the arsenic concentration, the City is providing the following statements as required by the US Environmental Protection Agency (EPA): Arsenic Educational Statement: While your drinking water meets EPA’s standard for arsenic, it does contain low levels of arsenic. EPA’s standard balances the current understanding of arsenic’s possible health effects against the costs of removing arsenic from drinking water. EPA continues to research the health effects of low levels of arsenic, which is a mineral known to cause cancer in humans at high concentrations and is linked to other health effects such as skin damage and circulatory problems. Arsenic Health Effects Statement: Some people who drink water containing arsenic in excess of the MCL over many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting cancer. Analyte Groundwater Concentration Units EPA Limit MCL Range Average EPA Limit MCLG Sample Date Possible Sources Alkalinty mg/L 210-231 221 NA NA 2007 Naturally present. Calcium mg/L 53-55 54 NA NA 2007 Erosion of natural deposits. Hardness Gr/gal 13.3* 13.3* NA NA 2007 Naturally present. mg/L 23* 23* NA NA 2007 Erosion of natural deposits. Manganese mg/L ND ND NA 0.05 2007 Naturally present. Contaminants that may be present in source water Sodium mg/L 47* 47* NA NA 2007 Naturally present. include the following: *Only one sample collected, as required. 1. Microbial contaminants, such as viruses and bacteria that may be from sewage treatment plants, septic 90th Percentile Units Reported Analyte Lead EPA Action Level mg/L EPA Limit MCLG Sample Date Number of sites above AL systems, agricultural livestock operations, or wildlife; Possible Sources 2. Inorganic contaminants, such as salts and metals, that 0.46 1.3 1.3 2007 Zero Erosion of natural deposits, home plumbing systems. can be naturally occurring or result from urban storm 3 15 0 2007 Zero Erosion of natural deposits, home plumbing systems. water runoff, industrial or domestic wastewater µg/L discharges, oil and gas production, mining, or farming; 3. Pesticides and herbicides that may come from a Disinfection Byproducts Overall Water System Concentrations Analyte Units Range Range Highest Average Highest Total µg/L Trihalomethanes 2.1-27 27 Total Haloacetic µg/L Acids ND-4.5 variety of sources such as agriculture, urban storm EPA Limit MCL EPA Limit MCLG Sample Date 80 NA 2007 Possible Sources By-product of drinking water chlorination Water Greenway Pyramid Peak System Surface Water Surface Water EPA Limit MCL Analyte Units Concentrations Concentrations Concentrations Total Coliforms Chlorine Residual P/A mg/L 1.11.69 1.69 1.131.5 1.5 4. Organic chemical contaminants, including synthetic and volatile organic chemicals, that are by-products of 4.5 60 NA 2007 By-product of drinking water chlorination industrial processes and petroleum production, and runoff, and septic systems; and Inorganics Units Turbidity NTU Turbidity Groundwater Concentration Units Range EPA Limit MCL Sample Date Possible Sources 0 2007 Erosion of natural deposits 2 2007 Erosion of natural deposits 4 NA 2007 Erosion of natural deposits 10 10 2007 Fertilizer runoff, erosion of natural deposits NA 2007 Erosion of natural deposits Range MCL MCLG Possible Sources 0.260 NA TT=1 NTU 0 Soil Runoff Arsenic µg/L ND-6 6 10 Barium mg/L 0.04 0.04 2 Fluoride mg/L ND-0.36 0.36 Nitrate mg/L ND-2.13 2.13 Sulfate mg/L 68.2 68.2 NA NTU 100.0% NA TT= % of samples <0.3 NTU 0 Soil Runoff 0.08 NA TT=1 NTU 0 Soil Runoff 100.0% NA TT= % of samples <0.3 NTU 0 Soil Runoff Turbidity has no health effects. However, turbidity can interfere with disinfection and provide a medium for microbial growth. Turbidity may indicate the presence of disease-causing organisms. These organisms include bacteria, viruses, and parasites that can cause symptoms such as nausea, cramps, diarrhea, and associated headaches. EPA Limit MCLG Due to the variation of the arsenic concentration, the City is providing the following statement as required by the US Environmental Protection Agency (EPA): Arsenic Educational Statement: While your drinking water meets EPA’s standard for arsenic, it does contain low levels of arsenic. EPA’s standard balances the current understanding of arsenic’s possible health effects against the costs of removing arsenic from drinking water. EPA continues to research the health effects of low levels of arsenic, which is a mineral known to cause cancer in humans at high concentrations and is linked to other health effects such as skin damage and circulatory problems. Unused Source Information The Environmental Protection Agency implemented a new Arsenic Rule in January 2006 lowering the allowed level of Arsenic from 50 ppb to 10 ppb. The City of Peoria responded by turning off wells which exceeded the new standard. Wells are a significant part of the overall water portfolio for the community and a significant capital investment. Technologies available to reduce Arsenic are continuing to be developed and operation and maintenance costs are varied. The table below provides a range of the Arsenic and Nitrate levels of wells within the Peoria main system which are currently unused sources for Peoria, but tested routinely. These ranges indicate that several of the UNUSED wells exceed the federal level for Arsenic or Nitrate, but please note that water that exceeded federal and state standards was not served to Peoria residents during 2007. The Vistancia wells had no exceedances for Arsenic or Nitrate in 2007. and mining activities. 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: 800-426-4791. Information on bottled water can be Radiological obtained from the FDA. Groundwater Concentration Analyte Units Highest Average Range The City of Peoria has performed an evaluation of various technologies for Arsenic mitigation and an implementation plan is being developed. The goal is to apply effective technology while minimizing the cost to Peoria customers. Therefore the wells which currently exceed the standard are continued to be tested per EPA rules and regulations to ensure these capital investments remain available for use at a later date. Nitrate levels occasionally rise when wells are not pumped for a significant period of time. occurring or can be the result of oil and gas production Highest Level Found EPA Limit MCL EPA Limit MCLG Sample Date Possible Sources Gross Alpha pCi/L ND-2.5 0.6 15 0 2007 Erosion of natural deposits Uranium µg/L 2.4-7.6 4.4 30 0 2007 Erosion of natural deposits Radon pCi/L 158-379 298 NA NA 2007 Erosion of natural deposits Radon is a radioactive gas that you cannot see, taste, or smell. It is found throughout the United States. Radon can move up through the ground and into a home through cracks and holes in the foundation. Radon can build up to high levels in all types of homes. Radon can also get into indoor air when released from tap water from showering, washing dishes, and other household activities. Compared to radon entering the home through soil, radon entering the home through tap water will in most cases be a small source of radon in indoor air. Radon is a known human carcinogen. Breathing air containing radon can lead to lung cancer. Drinking water containing radon may also cause increased risk of stomach cancer. If you are concerned about radon in your home, test the air in your home. Testing is inexpensive and easy. For additional information, call your state radon program or call EPA’s Radon Hotline (800-SOS-RADON). Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice from their health care providers. EPA/CDC EPA Sample MCLG Date EPA Limit MRDL Other Analysis 4 0 2007 NA 4 2007 4 means to lessen the risk of infection by Cryptosporidium Water System Concentrations Possible Sources Analyte Range MCL Possible Sources Naturally present Arsenic 2-20 ppb 10 ppb Erosion of natural deposits Water additive used to control microbes Nitrate 0.9-13.3 mg/L 10 mg/L Fertilizer runoff, erosion of natural deposits Sample Date EPA Limit MRDL and other microbial contaminants are available from the Units Total Coliforms P/A 0 two or more positive samples/month 0 2007 NA Naturally present mg/L 0.41 - 1.61 4 NA 2007 4 Water additive used to control microbes Chlorine Residual Giardia and Cryptosporidium were tested for, but not found at Pyramid Peak and Greenway Water Treatments Plants. EPA Limit MCL EPA Limit MCLG Analyte Range Highest 0-0.7% 0.7% 0.00% 0.00% 0.00% 0.00% 5% of monthly samples are positive 0.43- 1.73 1.73 water runoff, and residential uses; can also come from gas stations, urban storm water Analyte Analyte Unused Source Highest or from human activity. (Center for Disease Control) guidelines on appropriate Other Analysis Highest Range pick up substances resulting from the presence of animals Magnesium *Arsenic MCL is determined using a running annual average Range minerals, and in some cases radioactive material, and can 5. Radioactive contaminants that can be naturally- Inorganics Groundwater Concentrations contaminants in bottled water. springs, and wells. As water travels over the surface of the Turbidity Surface Water Treatment Plant regulations that limit the amount of certain contaminants in Drug Administration (FDA) regulations establish limits for Vistancia Area Water System Water Quality Data Copper mg/L ND-1.2 Possible Sources Environmental Protection Agency (EPA) prescribes land or through the ground, it dissolves naturally occurring 2007 Runoff/leaching from soil fumigant used on soybeans, cotton, pineapples, and orchards. 2007 In order to ensure that tap water is safe to drink, the water provided by public water systems. The Food and Copper and Lead Range EPA Limit MCLG ND Range EPA Limit MCL Some people who drink water containing DBCP in excess of the MCL over many years could experience reproductive problems and may have an increased risk of getting cancer. Groundwater Concentrations EPA Action Level (AL) mg/L Range Average Pyramid Peak Surface Water Concentrations Radiological * One sample collected, as required. 90th Percentile Units Reported Greenway Surface Water Concentrations Groundwater Concentrations Analyte Units Possible Sources Magnesium pH not applicable none detected not required Nephelometric Turbidity Unit: measure of how light is scattered by particulate matter in water P/A: Presence/Absence pCi/L: pico-Curies per liter: a measure of radioactivity ppt: parts per trillion; a unit of measurement equal to nanograms per liter Aesthetics Average NR MRDLG: Range: The highest and lowest measurement reported during the year. TT: Treatment Technique: a required process intended to reduce the level of a contaminant in drinking water. NA: ND: NR: NTU: millirem; a unit used to measure the effect of radiation on the human body Maximum Residual Disinfectant Level Goal: 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. Text in blue is language required by the US Environmental Protection Agency. Text in green is language required by the US Environmental Protection Agency. Groundwater Concentrations mrem: From the Environmental Protection Agency Level Found Possible Sources Safe Drinking Water Hotline: 800-426-4791.