{"dataset":{"name":"U.S. Drinking Water Quality — Contaminant Measurements","license":"https://creativecommons.org/licenses/by/4.0/","homepage":"https://www.thewatermap.com"},"meta":{"generatedAt":"2026-05-25T20:04:53.996Z"},"system":{"slug":"md__calvert__1040022-Calverton-School","name":"Calverton School","state":"MD","year":2024,"url":"https://www.thewatermap.com/water/md/calverton-school/2024","apiUrl":"https://www.thewatermap.com/api/water/md/calverton-school/2024","markdownUrl":"https://www.thewatermap.com/water/md/calverton-school/2024/llms.txt","coordinates":{"latitude":39.055383,"longitude":-76.9344612},"contaminantsMeasured":8,"contaminantsWithFederalLimit":8,"contaminantsAtOrAboveLimit":0,"contaminantsApproachingLimit":0,"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":0.3,"low":null,"high":null,"kind":"point","display":"0.3","units":"mg/L","statisticType":"running_annual_avg","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"0.3"},"federalStandard":{"type":"MRDL","value":4,"units":"mg/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":"mg/L","statisticType":"running_annual_avg","samplingContext":"system","rawVerbatim":"0.3"}]}]},{"family":"disinfection_byproduct","familyLabel":"Disinfection byproducts","contaminants":[{"analyteId":"haa5","name":"HAA5","family":"disinfection_byproduct","familyLabel":"Disinfection byproducts","casrn":null,"whatItIs":"Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter.","whyItMatters":"Long-term exposure above the federal limit is associated with an increased cancer risk.","measured":{"value":36,"low":null,"high":null,"kind":"point","display":"36","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"36"},"federalStandard":{"type":"MCL","value":60,"units":"ug/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0,"low":0,"high":0,"kind":"range","display":"0–0","units":"ug/L","statisticType":"range","samplingContext":"system","rawVerbatim":"0 - 0"},{"value":35.5,"low":35.5,"high":35.5,"kind":"range","display":"35.5–35.5","units":"ug/L","statisticType":"range","samplingContext":"system","rawVerbatim":"35.5 - 35.5"},{"value":0,"low":null,"high":null,"kind":"point","display":"0","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","rawVerbatim":"0"},{"value":36,"low":null,"high":null,"kind":"point","display":"36","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","rawVerbatim":"36"}]},{"analyteId":"tthm","name":"TTHM","family":"disinfection_byproduct","familyLabel":"Disinfection byproducts","casrn":null,"whatItIs":"Total trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter.","whyItMatters":"Long-term exposure above the federal limit is linked to liver, kidney, and central-nervous-system effects and increased cancer risk.","measured":{"value":56,"low":null,"high":null,"kind":"point","display":"56","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"56"},"federalStandard":{"type":"MCL","value":80,"units":"ug/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":56,"low":null,"high":null,"kind":"point","display":"56","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","rawVerbatim":"56"},{"value":1.8,"low":1.8,"high":1.8,"kind":"range","display":"1.8–1.8","units":"ug/L","statisticType":"range","samplingContext":"system","rawVerbatim":"1.8 - 1.8"},{"value":2,"low":null,"high":null,"kind":"point","display":"2","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","rawVerbatim":"2"},{"value":55.9,"low":55.9,"high":55.9,"kind":"range","display":"55.9–55.9","units":"ug/L","statisticType":"range","samplingContext":"system","rawVerbatim":"55.9 - 55.9"}]}]},{"family":"inorganic","familyLabel":"Inorganic chemicals","contaminants":[{"analyteId":"fluoride","name":"Fluoride","family":"inorganic","familyLabel":"Inorganic chemicals","casrn":"16984-48-8","whatItIs":"A mineral often added to drinking water to help prevent tooth decay.","whyItMatters":"Beneficial at low levels, but long-term exposure above the federal limit can cause bone disease and tooth mottling.","measured":{"value":0.194,"low":null,"high":null,"kind":"point","display":"0.194","units":"mg/L","statisticType":"max_single","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"0.194"},"federalStandard":{"type":"MCL","value":4,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.194,"low":null,"high":null,"kind":"point","display":"0.194","units":"mg/L","statisticType":"max_single","samplingContext":"system","rawVerbatim":"0.194"},{"value":0.194,"low":null,"high":null,"kind":"point","display":"0.194","units":"mg/L","statisticType":"range","samplingContext":"system","rawVerbatim":"0.194"}]}]},{"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":0.104,"low":null,"high":null,"kind":"point","display":"0.104","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","censored":false,"detectionLimit":null,"rawVerbatim":"0.104 mg/L"},"federalStandard":{"type":"AL","value":1.3,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.119,"low":0.0179,"high":0.119,"kind":"range","display":"0.0179–0.119","units":"mg/L","statisticType":"range","samplingContext":"at_the_tap","rawVerbatim":"0.0179 mg/L- 0.119 mg/L"},{"value":0.104,"low":null,"high":null,"kind":"point","display":"0.104","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","rawVerbatim":"0.104 mg/L"}]},{"analyteId":"lead","name":"Lead","family":"metal","familyLabel":"Metals","casrn":"7439-92-1","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":0.006,"low":null,"high":null,"kind":"point","display":"0.006","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","censored":false,"detectionLimit":null,"rawVerbatim":"0.006 mg/L"},"federalStandard":{"type":"AL","value":0.01,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.006,"low":null,"high":null,"kind":"point","display":"0.006","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","rawVerbatim":"0.006 mg/L"},{"value":0.0011,"low":0,"high":0.0011,"kind":"range","display":"0–0.0011","units":"mg/L","statisticType":"range","samplingContext":"at_the_tap","rawVerbatim":"ND (<0.0005 mg/L) – 0.0011 mg/L"}]}]},{"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":0.8,"low":null,"high":null,"kind":"point","display":"0.8","units":"pCi/L","statisticType":"max","samplingContext":"plant:Highe st Value","censored":false,"detectionLimit":null,"rawVerbatim":"0.8"},"federalStandard":{"type":"MCL","value":5,"units":"pCi/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.8,"low":null,"high":null,"kind":"point","display":"0.8","units":"pCi/L","statisticType":"max","samplingContext":"plant:Highe st Value","rawVerbatim":"0.8"},{"value":0.8,"low":0,"high":0.8,"kind":"range","display":"0–0.8","units":"pCi/L","statisticType":"range","samplingContext":"system","rawVerbatim":"0 - 0.8"}]},{"analyteId":"gross_beta","name":"Gross Beta Particle Activity","family":"radionuclide","familyLabel":"Radionuclides","casrn":null,"whatItIs":"Gross beta particle activity — a combined measure of beta-emitting radioactive substances.","whyItMatters":"Long-term exposure above the federal screening level increases cancer risk.","measured":{"value":19.1,"low":null,"high":null,"kind":"point","display":"19.1","units":"pCi/L","statisticType":"max","samplingContext":"plant:Highe st Value","censored":false,"detectionLimit":null,"rawVerbatim":"19.1"},"federalStandard":{"type":"MCL","value":50,"units":"pCi/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":19.1,"low":null,"high":null,"kind":"point","display":"19.1","units":"pCi/L","statisticType":"max","samplingContext":"plant:Highe st Value","rawVerbatim":"19.1"},{"value":19.1,"low":0,"high":19.1,"kind":"range","display":"0–19.1","units":"pCi/L","statisticType":"range","samplingContext":"system","rawVerbatim":"0 - 19.1"}]}]}],"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":0.3,"low":null,"high":null,"kind":"point","display":"0.3","units":"mg/L","statisticType":"running_annual_avg","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"0.3"},"federalStandard":{"type":"MRDL","value":4,"units":"mg/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":"mg/L","statisticType":"running_annual_avg","samplingContext":"system","rawVerbatim":"0.3"}]},{"analyteId":"haa5","name":"HAA5","family":"disinfection_byproduct","familyLabel":"Disinfection byproducts","casrn":null,"whatItIs":"Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter.","whyItMatters":"Long-term exposure above the federal limit is associated with an increased cancer risk.","measured":{"value":36,"low":null,"high":null,"kind":"point","display":"36","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"36"},"federalStandard":{"type":"MCL","value":60,"units":"ug/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0,"low":0,"high":0,"kind":"range","display":"0–0","units":"ug/L","statisticType":"range","samplingContext":"system","rawVerbatim":"0 - 0"},{"value":35.5,"low":35.5,"high":35.5,"kind":"range","display":"35.5–35.5","units":"ug/L","statisticType":"range","samplingContext":"system","rawVerbatim":"35.5 - 35.5"},{"value":0,"low":null,"high":null,"kind":"point","display":"0","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","rawVerbatim":"0"},{"value":36,"low":null,"high":null,"kind":"point","display":"36","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","rawVerbatim":"36"}]},{"analyteId":"tthm","name":"TTHM","family":"disinfection_byproduct","familyLabel":"Disinfection byproducts","casrn":null,"whatItIs":"Total trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter.","whyItMatters":"Long-term exposure above the federal limit is linked to liver, kidney, and central-nervous-system effects and increased cancer risk.","measured":{"value":56,"low":null,"high":null,"kind":"point","display":"56","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"56"},"federalStandard":{"type":"MCL","value":80,"units":"ug/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":56,"low":null,"high":null,"kind":"point","display":"56","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","rawVerbatim":"56"},{"value":1.8,"low":1.8,"high":1.8,"kind":"range","display":"1.8–1.8","units":"ug/L","statisticType":"range","samplingContext":"system","rawVerbatim":"1.8 - 1.8"},{"value":2,"low":null,"high":null,"kind":"point","display":"2","units":"ug/L","statisticType":"running_annual_avg","samplingContext":"system","rawVerbatim":"2"},{"value":55.9,"low":55.9,"high":55.9,"kind":"range","display":"55.9–55.9","units":"ug/L","statisticType":"range","samplingContext":"system","rawVerbatim":"55.9 - 55.9"}]},{"analyteId":"fluoride","name":"Fluoride","family":"inorganic","familyLabel":"Inorganic chemicals","casrn":"16984-48-8","whatItIs":"A mineral often added to drinking water to help prevent tooth decay.","whyItMatters":"Beneficial at low levels, but long-term exposure above the federal limit can cause bone disease and tooth mottling.","measured":{"value":0.194,"low":null,"high":null,"kind":"point","display":"0.194","units":"mg/L","statisticType":"max_single","samplingContext":"system","censored":false,"detectionLimit":null,"rawVerbatim":"0.194"},"federalStandard":{"type":"MCL","value":4,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.194,"low":null,"high":null,"kind":"point","display":"0.194","units":"mg/L","statisticType":"max_single","samplingContext":"system","rawVerbatim":"0.194"},{"value":0.194,"low":null,"high":null,"kind":"point","display":"0.194","units":"mg/L","statisticType":"range","samplingContext":"system","rawVerbatim":"0.194"}]},{"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":0.104,"low":null,"high":null,"kind":"point","display":"0.104","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","censored":false,"detectionLimit":null,"rawVerbatim":"0.104 mg/L"},"federalStandard":{"type":"AL","value":1.3,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.119,"low":0.0179,"high":0.119,"kind":"range","display":"0.0179–0.119","units":"mg/L","statisticType":"range","samplingContext":"at_the_tap","rawVerbatim":"0.0179 mg/L- 0.119 mg/L"},{"value":0.104,"low":null,"high":null,"kind":"point","display":"0.104","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","rawVerbatim":"0.104 mg/L"}]},{"analyteId":"lead","name":"Lead","family":"metal","familyLabel":"Metals","casrn":"7439-92-1","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":0.006,"low":null,"high":null,"kind":"point","display":"0.006","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","censored":false,"detectionLimit":null,"rawVerbatim":"0.006 mg/L"},"federalStandard":{"type":"AL","value":0.01,"units":"mg/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.006,"low":null,"high":null,"kind":"point","display":"0.006","units":"mg/L","statisticType":"p90","samplingContext":"zone:90TH Percentile: 90% of your water utility levels were less than","rawVerbatim":"0.006 mg/L"},{"value":0.0011,"low":0,"high":0.0011,"kind":"range","display":"0–0.0011","units":"mg/L","statisticType":"range","samplingContext":"at_the_tap","rawVerbatim":"ND (<0.0005 mg/L) – 0.0011 mg/L"}]},{"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":0.8,"low":null,"high":null,"kind":"point","display":"0.8","units":"pCi/L","statisticType":"max","samplingContext":"plant:Highe st Value","censored":false,"detectionLimit":null,"rawVerbatim":"0.8"},"federalStandard":{"type":"MCL","value":5,"units":"pCi/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":0.8,"low":null,"high":null,"kind":"point","display":"0.8","units":"pCi/L","statisticType":"max","samplingContext":"plant:Highe st Value","rawVerbatim":"0.8"},{"value":0.8,"low":0,"high":0.8,"kind":"range","display":"0–0.8","units":"pCi/L","statisticType":"range","samplingContext":"system","rawVerbatim":"0 - 0.8"}]},{"analyteId":"gross_beta","name":"Gross Beta Particle Activity","family":"radionuclide","familyLabel":"Radionuclides","casrn":null,"whatItIs":"Gross beta particle activity — a combined measure of beta-emitting radioactive substances.","whyItMatters":"Long-term exposure above the federal screening level increases cancer risk.","measured":{"value":19.1,"low":null,"high":null,"kind":"point","display":"19.1","units":"pCi/L","statisticType":"max","samplingContext":"plant:Highe st Value","censored":false,"detectionLimit":null,"rawVerbatim":"19.1"},"federalStandard":{"type":"MCL","value":50,"units":"pCi/L","enforceable":true},"status":{"key":"under","label":"Within the limit"},"breakdowns":[],"measurements":[{"value":19.1,"low":null,"high":null,"kind":"point","display":"19.1","units":"pCi/L","statisticType":"max","samplingContext":"plant:Highe st Value","rawVerbatim":"19.1"},{"value":19.1,"low":0,"high":19.1,"kind":"range","display":"0–19.1","units":"pCi/L","statisticType":"range","samplingContext":"system","rawVerbatim":"0 - 19.1"}]}]}}