Water analysis measures substances dissolved in water. Water is a very effective solute. Therefore, in nature it never occurs in a pure form, but rather it always contains "contaminants." These contaminants result in water characteristics such as hardness, electrical conductivity, corrosiveness, etc. Some of the substances in water pose a health risk when present in sufficient quantities, while others result in unaesthetic or nuisance conditions. Of the contaminants tested for by the MU Soil and Plant Testing Laboratory, only nitrate poses a health threat.

Water analysis results are compared to Secondary Maximum Contaminant Levels (nitrate excepted) Water that meets these standards should result in no unpleasant taste, appearance, odor or other side effects. For nitrate the Maximum Contaminant Level is that at which no deleterious health effects are anticipated.

The following list describes different water analyses and their relevance to domestic use.

• pH – A general water quality indicator, pH indicates whether water is acid or alkaline. The type of substances dissolved in water affects its pH. Acid water with a pH less than 6.0 will be corrosive to plumbing and facets, resulting in pitting or deposits. Low pH also tends to make metals and hardness minerals more soluble, which can dissolve metals from pipes and result in an unusual taste. Water with a pH greater than 8.5 will have a bitter soda-like taste.
• Total dissolved solids – This is a measure of all the inorganic substances dissolved in water, which includes minerals and salts. High values indicate an excess of some specific substance. Depending on the substance in excess, this can result in hard water, an objectionable taste (salty or bitter) or possibly a harmful health effect. Total dissolved solids is usually closely related to total dissolved salts and electrical conductivity.
• Electrical conductivity – Pure water is a poor conductor of electricity. As the concentration of dissolved salts (usually salts of sodium, calcium and magnesium, bicarbonate, chloride, and sulfate) increases in water, electrical conductivity increases. Electrical conductivity relates to the salinity of water.
• Hardness – Hard water is caused by calcium and magnesium dissolved in water. It is a relative term as shown in the table below. Hardness minerals react with soaps making them difficult to lather or causes them to form a scum, which is deposited on wash fixtures or clothes. These minerals in heated water will also precipitate as scale in appliances, pots, water heaters or pipes. Hard water has no known deleterious health effect.

• Bicarbonates – Bicarbonate is a negatively charged ion that associates with calcium and magnesium to form salt, which under the right conditions can precipitate from water as scale in pots and on pipes and fixtures. Bicarbonate can be a major contributor to water alkalinity.
• Sodium – Sodium is a metal that usually exists in water as a positively charged ion -- half of sodium chloride (table salt). There exists no national standard contaminant level for sodium, because the body readily excretes excess sodium. However, a maximum level of 20 ppm is recommended for people on low sodium diets. Water softening usually increases water sodium levels by about 8 ppm.
• Chloride – High chloride concentrations in water result in an objectionable salty taste and can cause corrosion of plumbing in hot water systems.
• Nitrate – Nitrate in water interferes with the body's capacity to absorb oxygen. High nitrate levels in water adversely affect infants and pregnant women. Infants are particularly susceptible – the condition is methemoglobinemia (infant cyanosis or blue baby disease). Adults are tolerant to much higher levels. The nitrate standard is established to protect infants less than one year old.

• Sulfate – Large amounts of sulfate in water can result in a bitter or medicinal taste; the formation of scale in boilers and heat exchangers; a laxative effect. The laxative effect is unlikely to occur at levels less than 500 ppm.
• Iron – High iron concentrations can impart an objectionable metallic taste or odor to water and cause a red or brown staining of laundry and porcelain fixtures. High concentrations do not pose a health hazard.
• Manganese – High manganese concentrations can impart a bitter taste to water and cause black or gray stains to laundry and porcelain fixtures. These stains can be more difficult to remove than iron stains. High concentrations do not pose a health hazard.
• Copper – Copper concentrations exceeding 1 ppm impart a bitter, metallic taste to water and at concentrations greater than 2 ppm may cause a blue-green staining of plumbing fixtures. Copper in water is not a health concern.
• Calcium and Magnesium – These minerals are responsible for water hardness.
• Potassium – Potassium has the same effect as sodium in water.

Irrigating with poor quality water usually doesn't have an immediate deleterious effect on plants. Rather, it results in a long-term hazard in which salts or sodium in the water accumulate in the soil and eventually decrease soil productivity. Because constituents in water are deposited onto the soil, interpreting water analysis is inextricably tied to soil properties. Sandy soils are less likely to accumulate salts or sodium than finely textured soils, and they can be more easily leached to remove salts or sodium. Soils with a high water table or poor drainage are more susceptible to salt or sodium accumulation.

The following list describes different water analyses and their relevance to irrigation water.

• Total dissolved solids – Total dissolved solids (effectively dissolved salts) is a measure of salinity. Dissolved salts conduct electricity in relation to their concentration, so electrical conductivity is another measure of salinity. Water salinity is derived primarily from the ions of calcium, magnesium, sodium, chloride and bicarbonates. Saline water induces a physiological drought in plants. Furthermore, salts applied in irrigation water are left behind in the soil following evapotranspiration, which leads to soil degradation. If saline water is to be used, it should be generously applied in order to leach salts and prevent salt accumulation.
• SAR – The sodium adsorption ratio (SAR) expresses the sodium hazard of water. It is calculated from sodium, calcium and magnesium concentrations in water. Calcium and magnesium counter sodium’s effect on soil. Sodium in irrigation water can accumulate in soil and result in undesirable physical soil characteristics. When wet, soil with high sodium levels has reduced water permeability and when dry soil becomes very hard. Sodium can also accumulate in soil to sufficiently large amounts such that plant uptake of sodium becomes toxic to the plant. Fine textured soils under low leaching conditions are most susceptible to degradation from irrigating with water that has moderate SAR values (3 to 6). From the perspective of inducing soil permeability problems, SAR and electrical conductivity both need to be considered. Low salinity water (usually low in calcium and magnesium) increases the deleterious effect of sodium in water.
• Sodium – Medium to high levels of sodium in water with low levels of calcium and magnesium can result in toxicity of some sensitive plants such as fruit trees and woody ornamentals. Annual crops are usually not affected except for sodium's affect on salinity and sodium buildup in soil.
• Chloride – Although an essential nutrient to crop growth, toxic levels of it in water can restrict plant growth. Water chloride concentrations up to 70 ppm are safe for all plants. From 70 to 140 ppm chloride, sensitive plants may incur some injury. From 140 to 350 ppm chloride, moderately tolerant plants will likely incur injury. Severe problems can be expected at concentrations above 350 ppm chloride. Woody and vine plants and stone fruits are susceptible to chloride toxicity.
• Calcium and magnesium – These minerals exist as positively charged ions in water, and they counteract the deleterious effect of sodium. Their concentrations are used in the calculation of SAR.
• Carbonates and bicarbonates – High levels of bicarbonate and carbonate in water increase the sodium hazard of water to a level greater than that indicated by SAR. Bicarbonates and carbonates combine with calcium and magnesium and precipitate from the soil solution as a whitish residue. This increases the concentration of sodium. The presence of carbonate versus bicarbonate is an indication of pH. Carbonate is present in water at a pH greater than 8.0.
• pH – A general water quality indicator, pH indicates whether water is acid or alkaline. Values less than 5.5 or greater than 8.5 should be investigated as to the source of the abnormal values. Acid water with a pH less than 6.0 will be corrosive to pipes.
• Nitrate – Nitrate in irrigation water is plant available. When concentrations are large enough, the nitrate in water can supplement the nitrogen applied in a regular fertilization program. In each acre-foot of one ppm NO3-N water, there is 2.72 lb of nitrogen. At concentrations greater than 30 ppm NO3-N, toxicity problems can be expected.
• Sulfate – Sulfate exists in water as a negatively charged ion. It contributes to the total salt content.
• Potassium – Potassium behaves much like sodium, but it is usually found in only small amounts in water.

Unsuitable water for livestock can reduce performance, cause illness or in severe cases cause death. When chronic poor animal performance continues despite changes in management, nutrition, environment and the health program, water quality problems may become suspect. Some natural water sources in Missouri are unsuitable for livestock, while contamination can spoil other sources.

The following list describes different water analyses and their relevance to livestock use.

• pH – A general water quality indicator, pH indicates whether water is acid or alkaline. The type of substances dissolved in water affects its pH. Acid water with a pH less than 6.0 will be corrosive to plumbing of water delivery systems. Low pH also tends to make metals and hardness minerals more soluble, which can dissolve metals from pipes and result in an unusual taste. Water with a pH greater than 8.5 will have a bitter soda-like taste.
• Total dissolved solids – Total dissolved solids is a measure of salinity. Water salinity may be derived from any inorganic substance dissolved in water, but the ions of magnesium, calcium, sodium and chloride are the primary contributors to salinity. Animal tolerance to salinity varies with age, species, water requirement, season of the year, and physiological condition. As the salinity of water increases, animals will increase their intake of water until the salinity increases to the point that animals will refuse to drink it. Use the table below for guidance. The slight salinity in good water may cause mild diarrhea to animals accustomed to better quality water. Animals may temporarily refuse water of fair quality or have diarrhea. Poor water is unsatisfactory for lactating or pregnant animals. Water that approaches the unacceptable level should be especially avoided during hot weather, although older animals may tolerate it during times of low stress.

• Electrical conductivity – Electrical conductivity is another measure of salinity.
• Sodium – Sodium exists in water as a positively charged ion. When associated with sulfate in water, it can cause diarrhea. Salt may need to be reduced in diets when sodium levels in water are high.
• Chloride – Chloride exists in water as a negatively charged ion. It contributes to a salty or brackish taste to water.
• Nitrate – Nitrate in water interferes with blood's capacity to absorb oxygen. Nitrate poisoning of animals can occur from excess consumption of nitrate from both water and feedstuffs. Water nitrate concentrations between 100 and 280 ppm should be avoided when high nitrate feedstuffs could contribute significant amounts of nitrate to animals' diet. Swine are very resistant to nitrate. Levels greater than 750 ppm are necessary before daily gain will decrease.
• Sulfate – High sulfate in water is usually a natural problem, i.e. not caused by man's activities. The primary problem with excessive sulfate in water is its laxative effect. Animals given a new water source of marginal sulfate levels may experience a temporary laxative effect until becoming acclimated to the water. The larger the animal the greater the laxative effect. Therefore, young animals are most susceptible to the laxative effect. High sulfate may also impart a bitter taste to water.
• Iron – Iron supplied by water constitutes only a small portion of iron available to animals. But because iron is inefficiently absorbed, it poses no health hazard to animals. High levels can cause a bad odor or taste.
• Manganese – High manganese concentrations can impart a bitter taste to water.
• Copper – In combination with phosphorus, copper plays a role in bone development. Ruminants are susceptible to copper toxicity. Problems with copper can also occur when dietary molybdenum is either low or high. Copper concentrations exceeding 1 ppm impart a bitter, metallic taste to water. Copper levels as low as 0.1 ppm may affect the flavor of cow's milk.
• Calcium and magnesium – These minerals are responsible for water hardness. High levels of magnesium in combination with sulfate can cause a laxative effect.

Water is an important dietary requirement for poultry as they typically consume twice as much water as feed. Unsuitable water can reduce performance, retard growth, curtail egg production, produce lower egg quality, cause illness or in severe cases cause death. When chronic poor bird performance continues despite changes in management, nutrition, environment or the health program, water quality problems may become suspect. Some natural water sources in Missouri are unsuitable for poultry, while contamination can spoil other sources.

The following list describes different water analyses and their relevance to poultry use.

• pH – A general water quality indicator, pH indicates whether water is acid or alkaline. The type of substances dissolved in water affects its pH. Acid water with a pH less than 6.3 may degrade performance, and a pH less than 6.0 is undesirable. Certain drugs that are administered in water may be poorly soluble in water with an improper pH. Consequently, birds may not get an adequate dose of the drug. Acid water can also be corrosive to the water deliver system. Water with a pH greater than 8.5 will have a bitter soda-like taste.
• Total dissolved solids – Total dissolved solids are effectively a measure of salinity. Water salinity may be derived from any inorganic substance dissolved in water, but the ions of magnesium, calcium, sodium and chloride are the primary contributors. As water salinity increases, birds will increase their intake of water until the salinity increases to the point that birds will refuse to drink it. Birds have the ability to adapt to slightly saline water, but abrupt changes from high quality to lesser quality water is likely to cause problems for birds. Tolerance to salinity varies with age, water requirement, season of the year and physiological condition. Fair to good water quality may cause temporary watery feces in birds not accustomed to the water. Poor water quality may cause refusal to drink and watery feces, increased mortality and decreased growth (especially for turkeys). Use the table below for guidance:
  • 0 to 1000 ppm = Excellent
  • 1000 to 2000 ppm = Good
  • 2000 to 3000 ppm = Fair
  • 3000 to 5000 ppm = Poor
  • 6000 ppm = Unacceptable
• Electrical conductivity – Electrical conductivity is another measure of water salinity.
• Sodium – Excessive sodium can have a laxative effect. A level greater than 50 ppm is detrimental if the sulfate level is 50 ppm or higher or the chloride level is 14 ppm or higher.
• Chloride – Excessive chloride has a detrimental effect on metabolism. A chloride level of 14 ppm or more can be detrimental if sodium is 50 ppm or more. If sodium is in the normal level, chloride levels as high as 25 ppm should not be a problem.
• Nitrate – Nitrate in water interferes with blood's capacity to absorb oxygen. Excess nitrate levels can affect weight gain, feed conversion and overall performance. Nitrate-N levels between 3 and 20 ppm have been suspected to affect performance. Effects are especially likely on young chickens.
• Sulfate – High sulfate in water is usually a natural problem, i.e. not caused by man's activities. The primary problem with excessive sulfate in water is its laxative effect. Birds given a new water source of marginal sulfate levels may experience a temporary laxative effect until becoming acclimated to the water. The effect is related to body size and young birds are most susceptible. High sulfate may also impart a bitter taste to water that can result in reduced water intake. Sulfate levels greater than 50 ppm may affect performance when sodium, magnesium or chloride levels are high.
• Iron – Iron supplied by water constitutes only a small portion of iron available to birds. But because iron is inefficiently absorbed, it poses no health hazard to birds. High iron levels can impart a bad odor or taste.
• Bicarbonates and carbonate – Bicarbonate and carbonate are negatively charged ions that associate with calcium and magnesium to form salt. Both can be a major contributors to water alkalinity.
• Manganese – High manganese concentrations can impart a bitter taste to water.
• Copper – Copper concentrations exceeding 1 ppm impart a bitter, metallic taste to water.
• Calcium and magnesium – These minerals are responsible for water hardness. Hard water when heated can result in the deposition of scale in pipes and water delivery equipment. High magnesium levels (> 50 ppm) can have a laxative effect when the sulfate or chloride levels are high.
• Potassium – Potassium has the same effect as sodium in water.
• Phosphate – While having no adverse effect on animals, phosphate in the ortho form can sequester calcium and magnesium to prevent clogging of pipes that supply the water. High phosphate levels may be an indicator of water contamination.