Recycled Water Quality Data

Lab technician titrating a water sample

Recycled water used in Dublin and San Ramon meets all regulatory requirements for unrestricted reuse as well as guidelines for managing salts in the groundwater basin under the Tri-Valley.

The DSRSD laboratory tests the parameters listed in the table on a monthly basis to ensure recycled water used for irrigation will not harm landscaping, as well as to monitor salts returned to the watershed.

Recycled Water Quality Data, Calendar Year 2024

Constituent Unit Average Range
pH standard unit 7.1 6.8 - 7.36
Total Alkalinity (as CaCO3) mg/L 254 202 - 314
Bicarbonate (as CaCO3) mg/L 254 202 - 314
Calcium mg/L 54 32.8 - 96
Magnesium mg/L 26 11 - 56
Calcium Hardness (as CaCO3) mg/L 136 82 - 240
Total Hardness (as CaCO3) mg/L 244 143 - 464
Chloride mg/L 191 138 - 230
Conductivity µmhos/cm 1314 1191 - 1749
Total Dissolved Solids mg/L 709 604 - 850
Ammonia (as N) mg/L 35.4 22 - 54
Nitrite (as N) mg/L 1.40 <0.10 -7.7
Nitrate (as N) mg/L 0.52 <0.10 - 2.9
Total Kjeldahl Nitrogen mg/L 34 20 - 51
Sulfate mg/L 161 116 - 218
Arsenic µg/L 0.56 <0.5 - 0.58
Boron mg/L 0.52 0.42 - 0.76
Chromium µg/L <2 N/A
Manganese µg/L 58 <50 - 70
Potassium mg/L 17 14 - 20
Selenium µg/L 0.55 <0.5 - 0.8
Silica (Total) mg/L 13.6 12.3 - 15
Sodium mg/L 170 160 - 190
Total Coliform Bacteria MPN/100 ml <1 (Median) <1 - 67.7
Copper ug/L 9.5 3.1 - 27
Lead ug/L <0.5 N/A
Zinc ug/L 20 <20 - 24

Abbreviations

  • mg/L = milligrams per liter
  • µmhos = micromhos per centimeter
  • µg/L = micrograms per liter
  • MPN = most probable number

 

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