Nitrates and nitrites are nitrogen-oxygen chemical units which combines with various organic and inorganic compounds. The major sources of nitrates or nitrites in drinking water include runoff from fertilizer use, sewage, and erosion of natural deposits. Nitrogen is an important parameter to monitor. Excessive amounts of nitrate or nitrite in water can cause methemoglobinaemia (blue baby syndrome) which can potentially be fatal. These contaminants can also cause adult illness and produce spontaneous abortion in cows. The EPA recommended limit for nitrates is 10 mg/L and for nitrites is 1 mg/L.

Lead is a metal found in natural deposits as ores containing other elements. It is sometimes used in household plumbing materials or in water service lines used to bring water from the main to the home. The main source of lead in drinking water is from corrosion of household plumbing systems. Lead and its compounds are poisonous and accumulate in the bone structure when ingested in amounts exceeding the natural elimination rate of about 300 ug per day. Accumulation of significant amounts of lead in the body may cause severe and permanent brain damage, convulsions, and death. The EPA recommended limit for lead is 0.015 mg/L.

pH is the measure of the hydrogen ion content of a solution. It measures the acidity or alkalinity of water. pH is measured on a scale of 0-14. A pH of 7 is neutral and is considered desirable in most cases. A pH above 7 indicates an alkaline, or basic, water condition that is not usually harmful in residential applications. A pH below 7 indicates an acidic water condition. When pH drops below 6.5, the water is corrosive to metal pipes. This not only means that the pipes , faucets, etc. can be damaged by low pH water, but also that the water can contain high levels of copper, lead, or zinc that have corroded out of the plumbing system. For this reason it is always desirable to raise the pH of the water as close to 7 as possible. Blue-green staining of fixtures and laundry are characteristic of acidic water. Green stains on plumbing fixtures are indicative of copper pipes being corroded by low pH water.

Manganese in water is a common, naturally occurring problem. It can also be introduced by industry. Manganese is usually found in combination with iron. It causes a bitter taste in water, and at concentrations above 0.05 mg/L, it causes dark scale in pipes and water heaters. High levels of manganese cause black staining of plumbing fixtures and laundry, and clogs up submersible pumps and pipes. The EPA recommended limit is 0.05 mg/L.

Chlorine is the prevailing choice for disinfection and biofouling control of drinking water, waste water, industrial water conditioning and swimming pool water. Too much chlorine can be as harmful as too little, so chlorine must be monitored carefully. High quantities of chlorine can cause health-related problems. The level of chlorine residual for drinking water must be checked regularly. Monitoring chlorine residual is essential for successful and efficient chlorination. A minimum free chlorine residual of 0.2 mg/L should be sufficient to maintain disinfection. Chlorine residual over 1.0 mg/L is too high and leaves a bad taste in the water.

Tannins are organic materials dissolved in the water. It is a product of decomposed plant material which occurs in natural waters. They can interfere with water softener filter resin beds and impart a distinctive yellow-brown color to the water. Tannins can also be associated with organically bound iron. Levels above 0.5 mg/L cause light brown or yellowish stains on laundry and fixtures. These levels can also affect the taste of foods and beverages.

Water hardness is caused almost entirely by calcium and magnesium ions. The amount of these ions and the amount of time the water stays in contact with them determines the water hardness level. Hard water causes scale formation in boilers, boiler feedwater heaters, feed lines, and economizers. In cooling water systems, scale will develop in heat exchange equipment and wherever water circulates and is exposed to a temperature change. Hard water also causes “soap curd” on fixtures, tile, dishes, and laundry. The water also has a low sudsing characteristic. Hard water aggravates dry skin conditions, takes the shine out of hair, and clings to skin. Water hardness is measured in grains per gallon. Hardness is measured as follows: Soft water is 0-1 GPG; Slightly hard water is 1-3.5 GPG; Moderately hard water is 3.5-7.0 GPG; Hard water is 7.0-10.5 GPG; Very hard water is 10.5 GPG & over.