{
  "city": "Washington",
  "state": "DC",
  "slug": "washington-dc",
  "hardness_facts": [
    {
      "utility": "DC Water",
      "measure": "Total hardness",
      "value_as_published": "Average 139 ppm (8 grains per gallon), range 84-194 ppm",
      "period": "Calendar year 2025",
      "source_title": "2026 Drinking Water Quality Report (DC Water), summarizing 2025 water quality test results",
      "source_url": "https://www.dcwater.com/waterreport"
    }
  ],
  "published_span_mg_per_l": [
    84,
    194
  ],
  "span_converted_from_grains": false,
  "usgs_class": "moderately hard to very hard",
  "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water",
  "notes": [],
  "local_details": {
    "disinfectant": {
      "text": "For most of the year, the Washington Aqueduct uses chloramine to keep DC water disinfected.",
      "kind": "chloramine",
      "source_title": "DC Water 2026 Drinking Water Quality Report",
      "source_url": "https://www.dcwater.com/waterreport",
      "evidence_ids": [
        "WASHIN-L-01"
      ]
    },
    "source_water": {
      "text": "DC water comes from the Potomac River, treated by the Washington Aqueduct and bought by DC Water.",
      "source_title": "DC Water 2026 Drinking Water Quality Report",
      "source_url": "https://www.dcwater.com/waterreport",
      "evidence_ids": [
        "WASHIN-L-02"
      ]
    },
    "seasonal": {
      "text": "For a short time each spring, the Aqueduct switches from chloramine to chlorine only.",
      "source_title": "DC Water 2026 Drinking Water Quality Report",
      "source_url": "https://www.dcwater.com/waterreport",
      "evidence_ids": [
        "WASHIN-L-03"
      ]
    }
  },
  "sources_checked_on": "2026-10-27",
  "site": "https://dcwatersystems.com/",
  "brand": "DC Water Systems by My Home Water System",
  "taking_requests": false
}