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Water Quality Parameter Reference Chart for Livestock

| TDS (mg/L) | Rating | Effects on Cattle | Recommended Action |

RanchSafety Team January 20, 2026 5 min read

WATER QUALITY PARAMETER REFERENCE CHART

How to Use This Chart

  • Locate your test result parameter in the left column
  • Compare your result to the guideline ranges
  • Follow recommended actions based on your reading
  • Consider total dietary intake from all sources

PHYSICAL PARAMETERS

Total Dissolved Solids (TDS)

TDS (mg/L)RatingEffects on CattleRecommended Action
<1,000ExcellentNo issuesNone
1,000-3,000GoodGenerally safe; slight palatability impact possibleMonitor
3,000-5,000FairMay cause temporary diarrhea in naive cattle; reduced intake possibleGradual adaptation
5,000-7,000MarginalNot for pregnant, lactating, or young stockSeek alternative for vulnerable animals
7,000-10,000PoorProduction losses likely; health risksStrongly consider alternatives
>10,000UnsuitableDo not useFind alternative source

pH

pH LevelRatingEffectsAction
<5.5AcidicCorrosive; leaches metals from pipes; palatability issuesInvestigate cause; may need treatment
5.5-6.5Slightly acidicGenerally acceptableMonitor
6.5-8.5IdealOptimal rangeNone
8.5-9.0Slightly alkalineGenerally acceptableMonitor
>9.0AlkalineReduces nutrient absorption; palatability issuesInvestigate cause

Hardness

Hardness (mg/L as CaCO3)ClassificationEffectAction
<60SoftNo livestock issuesNone
60-120Moderately hardNo livestock issuesNone
120-180HardGenerally acceptableNone
180-500Very hardMay reduce palatability; scale buildup in equipmentMonitor
>500Extremely hardEquipment issues; possible intake reductionConsider treatment

Temperature

TemperatureConsideration
<40°F (4°C)Risk of freezing; cattle drink less
40-65°F (4-18°C)Ideal range
65-80°F (18-27°C)Acceptable; increased bacterial growth
>80°F (27°C)Reduced intake; rapid algae/bacteria growth

MAJOR IONS

Sulfate (SO4)

Sulfate (mg/L)RatingEffectsAction
<250SafeNo issuesNone
250-500AcceptableMay cause temporary scours in naive cattleGradual introduction
500-1,000MarginalProduction impacts possible; scours likely initiallyLimit other sulfur sources; monitor closely
1,000-2,000PoorRisk of polioencephalomalacia (PEM); significant health riskAlternative strongly recommended
>2,000DangerousHigh PEM risk; do not useDo not use

Nitrate (as NO3)

Nitrate-N (mg/L)Nitrate (mg/L)RatingEffectsAction
<10<44SafeNo issuesNone
10-2044-88SafeGenerally safe for all cattleNone
20-4088-176CautionMay affect pregnant cattleMonitor breeding herd
40-100176-440MarginalSublethal effects; avoid for pregnant animalsTest feed for additional nitrates
100-200440-880DangerousHigh risk of nitrate poisoningDo not use, especially for pregnant cattle
>200>880LethalAcute poisoning likelyDo not use

Sodium (Na)

Sodium (mg/L)RatingEffectsAction
<500SafeNo issuesNone
500-1,000AcceptableGenerally safe; may contribute to TDS concernsMonitor TDS
1,000-2,000MarginalConcern for young/pregnant; adaptation neededGradual introduction
>2,000HighRisk of sodium toxicity with water restrictionDo not use; seek alternative

Chloride (Cl)

Chloride (mg/L)RatingEffectsAction
<500SafeNo issuesNone
500-1,000AcceptableContributes to TDSMonitor
1,000-2,000MarginalMay affect palatabilityConsider alternatives
>2,000HighPalatability issues; contributes to salinity stressSeek alternative

Calcium (Ca)

Calcium (mg/L)EffectsAction
<200No issuesNone
200-500Contributes to hardness; no health issuesNone
>500Very hard water; equipment concernsMonitor

Magnesium (Mg)

Magnesium (mg/L)RatingEffectsAction
<50SafeNo issuesNone
50-100AcceptableMay have laxative effectMonitor for scours
100-250MarginalLaxative effect likelyMonitor hydration
>250HighSignificant laxative effect; diarrheaSeek alternative

TRACE ELEMENTS / HEAVY METALS

Iron (Fe)

Iron (mg/L)RatingEffectsAction
<0.3SafeNo issuesNone
0.3-1.0MarginalStaining; slight taste impactAcceptable but monitor
1.0-10PoorReduced palatability; may reduce intakeConsider treatment
>10HighInterferes with other mineral absorptionTreatment or alternative needed

Copper (Cu)

Copper (mg/L)RatingEffectsAction
<0.5SafeNo issuesNone
0.5-1.0MarginalMonitor with high copper feedsReduce copper supplementation
>1.0DangerousRisk of copper accumulation and toxicitySeek alternative; monitor liver copper

Lead (Pb)

Lead (mg/L)RatingEffectsAction
<0.1SafeNo issuesNone
0.1-0.5ConcernChronic exposure riskInvestigate source; retest
>0.5DangerousLead poisoning riskDo not use; investigate source immediately

Arsenic (As)

Arsenic (mg/L)RatingEffectsAction
<0.2SafeNo issuesNone
0.2-0.5MarginalPotential chronic effectsInvestigate source; limit exposure
>0.5DangerousArsenic poisoning riskDo not use

Mercury (Hg)

Mercury (mg/L)RatingEffectsAction
<0.01SafeNo issuesNone
>0.01ConcernPotential neurological effectsInvestigate; avoid for long-term use

Zinc (Zn)

Zinc (mg/L)RatingEffectsAction
<5SafeNo issuesNone
5-25AcceptableGenerally safeMonitor
>25HighMay interfere with copper absorptionMonitor for copper deficiency signs

Manganese (Mn)

Manganese (mg/L)RatingEffectsAction
<0.05SafeNo issuesNone
0.05-0.5AcceptableMay cause stainingAcceptable
>0.5HighNeurological concerns with chronic exposureInvestigate; consider treatment

Molybdenum (Mo)

Molybdenum (mg/L)RatingEffectsAction
<0.5SafeNo issuesNone
0.5-1.0MarginalMay cause secondary copper deficiencyIncrease copper supplementation
>1.0HighHigh risk of copper deficiencySignificant copper supplementation; seek alternative

BIOLOGICAL PARAMETERS

Total Coliform Bacteria

Coliform (CFU/100 mL)RatingInterpretationAction
0ExcellentNo bacterial contaminationNone
1-10AcceptableMinor contamination; common in surface waterMonitor
10-100MarginalModerate contaminationIdentify source; treat or disinfect
>100PoorSignificant contaminationDo not use until treated

E. coli

E. coli (CFU/100 mL)RatingInterpretationAction
0SafeNo fecal contaminationNone
Any detectedConcernFecal contamination presentInvestigate source; treat; fence off contamination source

Blue-Green Algae (Cyanobacteria)

PresenceRatingAction
None visibleSafeNone
Light green tintMonitorCheck daily; consider preventive measures
Visible bloom/scumDangerousDo not allow animal access; test for cyanotoxins

QUICK REFERENCE: CRITICAL LIMITS

Parameters That Can Kill Quickly

ParameterLethal ThresholdSpeed of Death
Blue-green algae toxinsVariableMinutes to hours
Nitrate-N>200 mg/LHours
Sodium (with water restriction)Acute exposureHours to days
Sulfate (causing PEM)>2,000 mg/LDays

Parameters That Cause Chronic Problems

ParameterProblem ThresholdEffects
Lead>0.1 mg/LNeurological, reproductive
Arsenic>0.2 mg/LWasting, skin, GI
Copper>1.0 mg/LLiver accumulation
High TDS>5,000 mg/LProduction losses

WATER QUALITY BY LIVESTOCK CLASS

Most Sensitive to Water Quality

  • Newborn calves - Lowest tolerance
  • Pregnant cattle (especially late-term)
  • Lactating cattle
  • Young growing cattle
  • Adult cattle - Highest tolerance
Cattle ClassMaximum TDS (mg/L)
Newborn calves3,000
Pregnant cows (late-term)5,000
Lactating cows5,000
Growing cattle5,000
Mature bulls7,000
Dry cows7,000

SEASONAL ADJUSTMENTS

Summer Considerations

Evaporation concentrates all dissolved substances. Test more frequently (quarterly minimum) Algae risk highest. Cattle drink more = higher total mineral intake.

Winter Considerations

  • Frozen surface may concentrate minerals below
  • Ice can exclude some minerals (surface ice may be fresher)
  • Reduced intake may mask problems

Drought Considerations

  • All parameters become concentrated
  • Test before relying on diminished sources
  • Alternative sources may be needed

NOTES

This reference chart provides general guidelines. Actual safe levels depend on: Total dietary intake from all sources. Duration of exposure. Animal health status. Interactions between multiple parameters.

ABBREVIATIONS

Mg/L = milligrams per liter (same as ppm) ppm = parts per million. ppb = parts per billion. CFU = colony forming units. TDS = total dissolved solids. N = nitrogen. NO3 = nitrate. SO4 = sulfate. PEM = polioencephalomalacia.

Post in barn or office for quick reference Download at: www.animalsaferanch.com/downloads