{
  "city": "Boston",
  "state": "MA",
  "slug": "boston",
  "hardness_facts": [
    {
      "utility": "MWRA (for Boston Water and Sewer Commission)",
      "measure": "Typical total hardness",
      "value_as_published": "Approximately 16 mg/L, or 1 grain per gallon",
      "period": "Undated web page",
      "source_title": "Frequently Asked Questions About Drinking Water (MWRA)",
      "source_url": "https://www.mwra.com/your-water-system/drinking-water-quality/frequently-asked-questions-about-mwra-tap-water"
    },
    {
      "utility": "MWRA (for Boston Water and Sewer Commission)",
      "measure": "Total hardness, monthly reading",
      "value_as_published": "14.3 mg/L at the Carroll Water Treatment Plant",
      "period": "July 2026 sampling",
      "source_title": "Water Quality Update: An Analysis of July 2026 Sampling Data (MWRA)",
      "source_url": "https://www.mwra.com/media/file/wq-update-072026"
    }
  ],
  "published_span_mg_per_l": [
    14.3,
    20
  ],
  "span_converted_from_grains": false,
  "usgs_class": "soft",
  "usgs_class_source": "https://www.usgs.gov/water-science-school/science/hardness-water",
  "notes": [
    "The MWRA's July 2026 update describes hardness as about 15 to 20 mg/L, or about 1 grain per gallon."
  ],
  "local_details": {
    "disinfectant": {
      "text": "MWRA, which supplies Boston, disinfects with monochloramine, a compound of chlorine and ammonia.",
      "kind": "chloramine",
      "source_title": "MWRA 2025 Annual Water Quality Test Results",
      "source_url": "https://www.mwra.com/node/8620",
      "evidence_ids": [
        "BOSTON-L-01"
      ]
    },
    "source_water": {
      "text": "Boston water comes from MWRA's Quabbin and Wachusett reservoirs in central Massachusetts and is delivered by the Boston Water and Sewer Commission.",
      "source_title": "MWRA 2025 Annual Water Quality Test Results",
      "source_url": "https://www.mwra.com/node/8620",
      "evidence_ids": [
        "BOSTON-L-02"
      ]
    },
    "seasonal": {
      "text": "MWRA says a chlorine smell is more likely in summer, when water is warmer, and that algae in its reservoirs can cause an earthy taste in spring and fall.",
      "source_title": "MWRA tap water FAQ",
      "source_url": "https://www.mwra.com/your-water-system/drinking-water-quality/frequently-asked-questions-about-mwra-tap-water",
      "evidence_ids": [
        "BOSTON-L-03"
      ]
    }
  },
  "sources_checked_on": "2026-10-27",
  "site": "https://bostonwatersystems.com/",
  "brand": "Boston Water Systems by My Home Water System",
  "taking_requests": false
}