{"dataset":{"name":"U.S. Drinking Water Quality — Contaminant Measurements","license":"https://creativecommons.org/licenses/by/4.0/","homepage":"https://www.thewatermap.com"},"meta":{"generatedAt":"2026-07-09T22:40:50.194Z"},"system":{"slug":"md__baltimore__0030202-Chapel-Hill-Water-System","name":"Chapel Hill Water System","state":"MD","year":2024,"url":"https://www.thewatermap.com/water/md/chapel-hill/2024","apiUrl":"https://www.thewatermap.com/api/water/md/chapel-hill/2024","markdownUrl":"https://www.thewatermap.com/water/md/chapel-hill/2024/llms.txt","coordinates":{"latitude":39.2918356,"longitude":-76.5947227},"contaminantsMeasured":7,"contaminantsWithFederalLimit":7,"contaminantsAtOrAboveLimit":1,"contaminantsApproachingLimit":1,"source":{"type":"Consumer Confidence Report (CCR)","description":"Figures are transcribed from the water utility's own annual Consumer Confidence Report, cross-checked by a second model, and approved by a person before publishing."},"families":[{"family":"disinfectant","familyLabel":"Disinfectants","contaminants":[{"analyteId":"chlorine","name":"Chlorine","family":"disinfectant","familyLabel":"Disinfectants","casrn":null,"whatItIs":"A disinfectant added to drinking water to kill bacteria and viruses.","whyItMatters":"Effective and necessary, but high residual levels can cause taste and odor issues; the EPA caps the residual disinfectant level.","measured":{"value":6,"low":3.54,"high":6,"kind":"range","display":"3.54–6","units":"mg/L","statisticType":"range","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"3.54 – 6.00"},"federalStandard":{"type":"MCL","value":4,"units":"mg/L","enforceable":true},"status":{"key":"over","label":"At or above the limit"},"breakdowns":[],"measurements":[{"value":6,"low":3.54,"high":6,"kind":"range","display":"3.54–6","units":"mg/L","statisticType":"range","samplingContext":"system","rawVerbatim":"3.54 – 6.00"}]}]},{"family":"inorganic","familyLabel":"Inorganic chemicals","contaminants":[{"analyteId":"nitrate","name":"Nitrate","family":"inorganic","familyLabel":"Inorganic chemicals","casrn":"14797-55-8","whatItIs":"A compound from fertilizer runoff, septic systems, and erosion of natural deposits.","whyItMatters":"Levels above the federal limit can cause 'blue baby syndrome,' a serious oxygen-transport condition in infants.","measured":{"value":6.46,"low":5.62,"high":6.46,"kind":"range","display":"5.62–6.46","units":"mg/L","statisticType":"range","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"5.62 - 6.46"},"federalStandard":{"type":"MCL","value":10,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":6.46,"low":5.62,"high":6.46,"kind":"range","display":"5.62–6.46","units":"mg/L","statisticType":"range","samplingContext":"system","rawVerbatim":"5.62 - 6.46"},{"value":6.46,"low":null,"high":null,"kind":"point","display":"6.46","units":"mg/L","statisticType":"max","samplingContext":"system","rawVerbatim":"6.46"}]}]},{"family":"metal","familyLabel":"Metals","contaminants":[{"analyteId":"copper","name":"Copper","family":"metal","familyLabel":"Metals","casrn":"7440-50-8","whatItIs":"A metal that enters water from corroding household plumbing.","whyItMatters":"Short-term exposure causes stomach distress; long-term exposure can damage the liver and kidneys.","measured":{"value":0.36,"low":null,"high":null,"kind":"point","display":"0.36","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","censored":false,"detectionLimit":null,"rawVerbatim":"0.36"},"federalStandard":{"type":"AL","value":1.3,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.36,"low":null,"high":null,"kind":"point","display":"0.36","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","rawVerbatim":"0.36"},{"value":0,"low":null,"high":null,"kind":"non_detect","display":"Not detected","units":"mg/L","statisticType":"range","samplingContext":"at_the_tap","rawVerbatim":"<.005"}]},{"analyteId":"lead","name":"Lead","family":"metal","familyLabel":"Metals","casrn":null,"whatItIs":"A toxic metal that leaches into water from old service lines, solder, and plumbing fixtures.","whyItMatters":"There is no safe level of lead; it harms brain development in children and raises blood pressure in adults. The EPA sets an action level, not a health goal above zero.","measured":{"value":0.002,"low":null,"high":null,"kind":"point","display":"0.002","units":"mg/L","statisticType":"p90","samplingContext":"at_the_tap","censored":false,"detectionLimit":null,"rawVerbatim":"lead 90th-percentile 0.002 mg/L (EPA SDWIS LCR, 1 round(s), 2024)"},"federalStandard":{"type":"AL","value":0.015,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.002,"low":null,"high":null,"kind":"point","display":"0.002","units":"mg/L","statisticType":"p90","samplingContext":"at_the_tap","rawVerbatim":"lead 90th-percentile 0.002 mg/L (EPA SDWIS LCR, 1 round(s), 2024)"}]}]},{"family":"other","familyLabel":"Other","contaminants":[{"analyteId":"nitrate_nitrite","name":"Nitrate Nitrite","family":"other","familyLabel":"Other","casrn":null,"whatItIs":null,"whyItMatters":null,"measured":{"value":9.2,"low":null,"high":null,"kind":"point","display":"9.2","units":"mg/L","statisticType":"max","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"9.2"},"federalStandard":{"type":"MCL","value":10,"units":"mg/L","enforceable":true},"status":{"key":"approaching","label":"Approaching the limit"},"breakdowns":[],"measurements":[{"value":9.2,"low":null,"high":null,"kind":"point","display":"9.2","units":"mg/L","statisticType":"max","samplingContext":"system","rawVerbatim":"9.2"},{"value":9.2,"low":null,"high":null,"kind":"point","display":"9.2","units":"mg/L","statisticType":"range","samplingContext":"system","rawVerbatim":"9.2"}]}]},{"family":"radionuclide","familyLabel":"Radionuclides","contaminants":[{"analyteId":"combined_radium","name":"Combined Radium","family":"radionuclide","familyLabel":"Radionuclides","casrn":null,"whatItIs":"Combined radium-226 and radium-228 — naturally occurring radioactive elements.","whyItMatters":"Long-term exposure above the federal limit increases the risk of bone cancer.","measured":{"value":0.3,"low":null,"high":null,"kind":"point","display":"0.3","units":"pCi/L","statisticType":"max_single","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"0.3"},"federalStandard":{"type":"MCL","value":5,"units":"pCi/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.3,"low":null,"high":null,"kind":"point","display":"0.3","units":"pCi/L","statisticType":"max_single","samplingContext":"system","rawVerbatim":"0.3"},{"value":0.3,"low":null,"high":null,"kind":"point","display":"0.3","units":"pCi/L","statisticType":"range","samplingContext":"system","rawVerbatim":"0.3"}]},{"analyteId":"gross_alpha","name":"Gross Alpha","family":"radionuclide","familyLabel":"Radionuclides","casrn":null,"whatItIs":"Gross alpha particle activity — a combined measure of alpha-emitting radioactive substances.","whyItMatters":"Long-term exposure above the federal limit increases cancer risk.","measured":{"value":2.4,"low":null,"high":null,"kind":"point","display":"2.4","units":"pCi/L","statisticType":"max_single","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"2.4"},"federalStandard":{"type":"MCL","value":15,"units":"pCi/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":2.4,"low":null,"high":null,"kind":"point","display":"2.4","units":"pCi/L","statisticType":"max_single","samplingContext":"system","rawVerbatim":"2.4"},{"value":2.4,"low":null,"high":null,"kind":"point","display":"2.4","units":"pCi/L","statisticType":"range","samplingContext":"system","rawVerbatim":"2.4"}]}]}],"contaminants":[{"analyteId":"chlorine","name":"Chlorine","family":"disinfectant","familyLabel":"Disinfectants","casrn":null,"whatItIs":"A disinfectant added to drinking water to kill bacteria and viruses.","whyItMatters":"Effective and necessary, but high residual levels can cause taste and odor issues; the EPA caps the residual disinfectant level.","measured":{"value":6,"low":3.54,"high":6,"kind":"range","display":"3.54–6","units":"mg/L","statisticType":"range","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"3.54 – 6.00"},"federalStandard":{"type":"MCL","value":4,"units":"mg/L","enforceable":true},"status":{"key":"over","label":"At or above the limit"},"breakdowns":[],"measurements":[{"value":6,"low":3.54,"high":6,"kind":"range","display":"3.54–6","units":"mg/L","statisticType":"range","samplingContext":"system","rawVerbatim":"3.54 – 6.00"}]},{"analyteId":"nitrate","name":"Nitrate","family":"inorganic","familyLabel":"Inorganic chemicals","casrn":"14797-55-8","whatItIs":"A compound from fertilizer runoff, septic systems, and erosion of natural deposits.","whyItMatters":"Levels above the federal limit can cause 'blue baby syndrome,' a serious oxygen-transport condition in infants.","measured":{"value":6.46,"low":5.62,"high":6.46,"kind":"range","display":"5.62–6.46","units":"mg/L","statisticType":"range","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"5.62 - 6.46"},"federalStandard":{"type":"MCL","value":10,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":6.46,"low":5.62,"high":6.46,"kind":"range","display":"5.62–6.46","units":"mg/L","statisticType":"range","samplingContext":"system","rawVerbatim":"5.62 - 6.46"},{"value":6.46,"low":null,"high":null,"kind":"point","display":"6.46","units":"mg/L","statisticType":"max","samplingContext":"system","rawVerbatim":"6.46"}]},{"analyteId":"copper","name":"Copper","family":"metal","familyLabel":"Metals","casrn":"7440-50-8","whatItIs":"A metal that enters water from corroding household plumbing.","whyItMatters":"Short-term exposure causes stomach distress; long-term exposure can damage the liver and kidneys.","measured":{"value":0.36,"low":null,"high":null,"kind":"point","display":"0.36","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","censored":false,"detectionLimit":null,"rawVerbatim":"0.36"},"federalStandard":{"type":"AL","value":1.3,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.36,"low":null,"high":null,"kind":"point","display":"0.36","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","rawVerbatim":"0.36"},{"value":0,"low":null,"high":null,"kind":"non_detect","display":"Not detected","units":"mg/L","statisticType":"range","samplingContext":"at_the_tap","rawVerbatim":"<.005"}]},{"analyteId":"lead","name":"Lead","family":"metal","familyLabel":"Metals","casrn":null,"whatItIs":"A toxic metal that leaches into water from old service lines, solder, and plumbing fixtures.","whyItMatters":"There is no safe level of lead; it harms brain development in children and raises blood pressure in adults. The EPA sets an action level, not a health goal above zero.","measured":{"value":0.002,"low":null,"high":null,"kind":"point","display":"0.002","units":"mg/L","statisticType":"p90","samplingContext":"at_the_tap","censored":false,"detectionLimit":null,"rawVerbatim":"lead 90th-percentile 0.002 mg/L (EPA SDWIS LCR, 1 round(s), 2024)"},"federalStandard":{"type":"AL","value":0.015,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.002,"low":null,"high":null,"kind":"point","display":"0.002","units":"mg/L","statisticType":"p90","samplingContext":"at_the_tap","rawVerbatim":"lead 90th-percentile 0.002 mg/L (EPA SDWIS LCR, 1 round(s), 2024)"}]},{"analyteId":"nitrate_nitrite","name":"Nitrate Nitrite","family":"other","familyLabel":"Other","casrn":null,"whatItIs":null,"whyItMatters":null,"measured":{"value":9.2,"low":null,"high":null,"kind":"point","display":"9.2","units":"mg/L","statisticType":"max","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"9.2"},"federalStandard":{"type":"MCL","value":10,"units":"mg/L","enforceable":true},"status":{"key":"approaching","label":"Approaching the limit"},"breakdowns":[],"measurements":[{"value":9.2,"low":null,"high":null,"kind":"point","display":"9.2","units":"mg/L","statisticType":"max","samplingContext":"system","rawVerbatim":"9.2"},{"value":9.2,"low":null,"high":null,"kind":"point","display":"9.2","units":"mg/L","statisticType":"range","samplingContext":"system","rawVerbatim":"9.2"}]},{"analyteId":"combined_radium","name":"Combined Radium","family":"radionuclide","familyLabel":"Radionuclides","casrn":null,"whatItIs":"Combined radium-226 and radium-228 — naturally occurring radioactive elements.","whyItMatters":"Long-term exposure above the federal limit increases the risk of bone cancer.","measured":{"value":0.3,"low":null,"high":null,"kind":"point","display":"0.3","units":"pCi/L","statisticType":"max_single","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"0.3"},"federalStandard":{"type":"MCL","value":5,"units":"pCi/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.3,"low":null,"high":null,"kind":"point","display":"0.3","units":"pCi/L","statisticType":"max_single","samplingContext":"system","rawVerbatim":"0.3"},{"value":0.3,"low":null,"high":null,"kind":"point","display":"0.3","units":"pCi/L","statisticType":"range","samplingContext":"system","rawVerbatim":"0.3"}]},{"analyteId":"gross_alpha","name":"Gross Alpha","family":"radionuclide","familyLabel":"Radionuclides","casrn":null,"whatItIs":"Gross alpha particle activity — a combined measure of alpha-emitting radioactive substances.","whyItMatters":"Long-term exposure above the federal limit increases cancer risk.","measured":{"value":2.4,"low":null,"high":null,"kind":"point","display":"2.4","units":"pCi/L","statisticType":"max_single","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"2.4"},"federalStandard":{"type":"MCL","value":15,"units":"pCi/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":2.4,"low":null,"high":null,"kind":"point","display":"2.4","units":"pCi/L","statisticType":"max_single","samplingContext":"system","rawVerbatim":"2.4"},{"value":2.4,"low":null,"high":null,"kind":"point","display":"2.4","units":"pCi/L","statisticType":"range","samplingContext":"system","rawVerbatim":"2.4"}]}]}}