Iron: Iron levels above 0.3 mg/L can discolor fixtures and laundry and may impart a metallic taste to the water. Iron is frequently present in water because of the large amounts present in soil. Corrosive water will also pick up iron from pipes. Common methods for removing iron from the water are a water softener or oxidizing filter.

Lead: Lead enters drinking water primarily as a result of the corrosion, or wearing away, of materials containing lead in the water distribution system and plumbing. These materials include lead-based solder used to join copper pipe, brass and chrome plated faucets, and in some cases, pipes made of lead. Dissolved oxygen, low pH (acidity), and low mineral content in water (soft water) are common causes of corrosion. Exposure to lead in water can be reduced by “flushing” the tap before use (running the cold water faucet until the water gets noticeably colder, usually about 15-30 seconds) Do not cook with or drink water from the hot tap. Hot water can dissolve more lead, more quickly, than cold water.

Manganese: Manganese at levels greater than .05 mg/L may produce a brownish black stain in laundry and on fixtures and impart an objectionable odor and taste. It is usually found along with iron in soil with a high mineral content. Oxidation followed by a greensand filter is a common method of manganese removal. Treatment option: water softener or oxidizing filter

Nitrate nitrogen: An elevated nitrate nitrogen level may be an indication that agricultural fertilizer or waste disposal is polluting the water. The allowable level of 10 mg/L has been established to prevent a disease called methemoglobinemia (blue baby disease) in infants. Nitrates can be removed by reverse osmosis.

Odor: Odor in the water can be caused by foreign matter such as organic compounds, inorganic salts or dissolved gases. These materials may come from domestic, agricultural or natural sources. The allowable level has been set according to aesthetic values but acceptable waters should be free of any objectionable odor. Treatment option: carbon filter

pH: pH is a measure of the acid or alkaline content of water. Water with a low pH (acidic) is corrosive to plumbing and may cause leaching of toxic metals such as lead or copper, blue-green staining of fixtures and metallic taste. Left untreated, acidic water will thin copper pipes and lead to pinhole leaks in plumbing system. Treatment option: Neutralizer.

Sodium: For healthy persons, the sodium content of water is relatively unimportant. Persons following a low sodium diet because of hypertension, kidney, or cardiovascular disease should be concerned with an elevated level of sodium. The usual low sodium diet allows 20 mg/L in the drinking water. Elevated sodium levels are likely to be seen with the use of a water softener. Other possible causes are run-off from road salting or sewage contamination. Treatment option: Reverse Osmosis

Sulfate: Sulfate in drinking water has no beneficial effects. The desirable limit is 250 mg/L. At higher concentrations sulfate may have a laxative effect and cause taste deterioration. Treatment option: carbon filter

Tannins: Tannins (fulvic or humic acid) are a natural organic material that can be the byproducts of nature’s fermentation process, be created as water passes through peaty soil and decaying vegetation. This can cause water to have a faint yellow to tea-like color, and can cause yellow staining on fabrics, fixtures, china and laundry. Tannins may give a tangy or tart aftertaste to water. They may also cause water to have a musty or earthy odor. Tannins are more common in surface water supplies and shallow wells than in deep wells. Water in marsh, low-lying, or coastal areas is also more susceptible to tannins. Common tannin treatment uses an anion exchange resin.

Turbidity: Turbidity is the presence of suspended material such as clay, silt, plankton, finely divided organic material and other inorganic material. Turbidity in excess of 5 units is detectable in a glass of water and is usually objectionable for aesthetic reasons. The most common method of removing turbidity is with a cartridge filter system for sand/sediment. When any physical property exceeds the AL , knowledge concerning the chemical quality is important in order to determine what treatment, if any, is required to make the water acceptable for use.