Serving roughly 5,504 people in Merced County, California.
Data current as of July 2026
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Results for HILMAR COUNTY WATER DISTRICT
1 water provider directly on file, serving roughly 5,504 people in Merced County, California.
Quick answer: HILMAR COUNTY WATER DISTRICT has no violation currently counted toward its compliance status. EPA's record shows a Nitrate violation dating to 07/01/1983 (43 years ago) — because it's more than five years past its deadline, EPA's policy no longer treats it as part of this system's current standing, though it remains on the public record.
Lead Summary
Nitrate
Lead
Copper, Free
Arsenic
Alkalinity, Total
Alkalinity, Bicarbonate
Magnesium
Sodium
Calcium
Hardness, Total (ASCACO3)
TDS
Sulfate
Chloride
Turbidity
Radium-228
Combined Uranium
pH
Manganese
Barium
Conductivity (at 25°C)
Utility HILMAR COUNTY WATER DISTRICTPopulation served 5,504Owner Local government
Older violation on record
Violations on file
Nitrate
Older/archived health-based violation
Found at 1 of 1 provider
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Contaminants found
Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0 mg/L (ppm)
12/31/2025
Lead
Detected: 37.4 UG/L (ppb)
9/18/2025
A metal that can leach from old pipes, solder, and fixtures. Current medical guidance holds there is no truly safe level of lead exposure, especially for children and pregnant women.
Copper, Free
Detected: 2300 UG/L (ppb)
9/18/2025
Arsenic
Detected: 10.6 UG/L (ppb)
10/21/2025
Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.
Combined Uranium
Detected: 1.62 PCI/L
6/24/2025
A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.
Manganese
Detected: 65.2 UG/L (ppb)
6/24/2025
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Barium
Detected: 137 UG/L (ppb)
6/24/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Nitrate
Detected: 2.24 MG/L (ppm)
10/28/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Sulfate
Detected: 10.1 MG/L (ppm)
6/24/2025
Chloride
Detected: 115 MG/L (ppm)
6/24/2025
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 11.9 MG/L (ppm)
6/24/2025
Sodium
Detected: 75.6 MG/L (ppm)
6/24/2025
Calcium
Detected: 29.5 MG/L (ppm)
6/24/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Hardness, Total (ASCACO3)
Detected: 123 MG/L (ppm)
6/24/2025
pH
Detected: 6.7 PH
6/24/2025
A measure of how acidic or basic the water is (7 is neutral). Affects taste and plumbing, not a direct health measure.
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 110 MG/L (ppm)
6/24/2025
Other
Additional substances tested that don't fit neatly into the categories above
Alkalinity, Total
Detected: 110 MG/L (ppm)
6/24/2025
TDS
Detected: 362 MG/L (ppm)
6/24/2025
Turbidity
Detected: 0.2 NTU
6/24/2025
A measure of water cloudiness from suspended particles.
Radium-228
Detected: 0.236 PCI/L
8/6/2025
Conductivity (at 25°C)
Detected: 606 UMHO/CM
6/24/2025
Filtration considerations: See the table below for how whole-house carbon, under-sink reverse osmosis, and under-sink carbon systems compare against what's actually on file here. These are general system types, not a specific product recommendation.