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Analytical Chemistry Laboratory:
Water Quality Limits

The table below shows the acceptable chemical limits for various uses of water. There is also a separate discussion about evaluating an laboratory analysis and a price list for these analyses.

Limits for Various Uses (mg/L)
Parameter Domestic (2) Drinking (3) Stock (4, 5) Irrigation (4, 5)
Anions        
Chloride 250 (a) 250 (a)    
Sulfate 600 (a) 250 (a) 1000 (4, *)  
Nitrate as NO3 45.0 45 45.0*  
Nitrite as NO2 4.5 4.5 4.5  
Fluoride
(Based on water temperature)
1.8 (50.0-50.3o F.) 4.0; 2.0 (a) 2.0 1.0
  1.5 (50.4-70.6o F.)      
  1.2 (70.7-90.6o F.)      
Total Dissolved Solids (TDS) 1000 (a) 500 (a) 3000* small animals 500* no effects
      5000* poultry 500-1000* affects sensitive crops
      7000* large animals 1000-2000* affects many crops
        2000-3000* only for tolerant crops
Hardness 0-75 = soft      
  75-150 = moderately hard      
  150-300 = hard      
  >300 = extremely hard      
pH between 6 and 9 (a) 6.5-8.5 (a)    
         
Trace Metals
Aluminum   0.05-0.26 (a) 5.0 5.0
Antimony   0.006    
Arsenic 0.1 0.01 0.2 0.1
Barium 1.0 2.0    
Berylium   0.004    
Boron     5.0 0.75
Cadmium 0.01 0.005 0.05 0.01
Chromium (total) 0.05 0.1 1.0 0.1
Cobalt     5.0 0.5
Copper 1.0 (a) 1.3 (al) 0.5  
Cyanide 0.1 0.2    
Iron 1 0.3    
Lead 0.05 0.015 (al) 0.1  
Manganese 0.2 (a) 0.05 (a)   <10.0 long term
Mercury 0.002 0.002 0.01  
Molybdenum       1.0
Nickel   0.1   0.2
Selenium 0.05 0.05 0.05 0.02
Silver 0.05 0.05    
Uranium 5.0 0.03    
Zinc 10.0 5.0 (a) 24  

Notes

  1. Analysed only for parameters indicated; mg/L = milligrams per liter = parts per million.
  2. New Mexico groundwater standards for domestic supply. Standards are enforceable including aesthetic.
  3. Enforceable U.S.E.P.A. Drinking Water Standards. Secondary or aesthetic standards are only recommendations.
  4. U.S. Environmental Protection Agency, 1973, Water Quality Criteria-1972; Government Printing Office, Washington, D.C.
  5. New Mexico Water Quality Control Commission Regulations as amended through January, 1992; New Mexico Environment Department.
  • (a) = Secondary Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects (tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water.
  • (al) = EPA Action Level
  • (p) = proposed
  • * Recommendations only

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