Hardness

Water hardness is classified as follows:

• Soft water: 0 - 1 grains per gallon
• Slightly hard water: 1 - 3.5 grains per gallon
• Moderately hard water: 3.5 - 7 grains per gallon
• Hard water: 7 - 10.5 grains per gallon
• Very Hard water: Over 10.5 grains per gallon

White scale build-up will start to form at levels of 2 GPG and higher. Water hardness refers to the amount of calcium and magnesium in the water, measured in grains per gallon (GPG). 1 GPG is equivalent to 17.1 parts per million (PPM) or milligrams per liter (mg/L).

Iron

The EPA recommends iron levels under 0.3 ppm. Staining on plumbing fixtures, clothes, and appliances can occur at levels of 0.3 ppm or higher.

• Ferrous Iron: “Clear water” iron, invisible until oxidized. This form can attach to softening ion exchange resin and be removed.
• Ferric Iron: “Red water” iron, already oxidized before entering the home. This type requires specific iron treatment systems as it won’t be removed by a softener.

Manganese

Manganese thrives in warm, stagnant environments such as filter housings and water heaters. It can cause a rotten egg or sulfur odor at levels of 0.05 ppm and higher and can attach to softening resin for removal.

TDS (Total Dissolved Solids)

The EPA recommends TDS levels under 500 mg/L. Levels over 500 mg/L may cause deposits, staining, and an altered taste.

pH

Neutral pH is 7.0. Ideal pH levels range between 6.5 and 8.5.

• Acidic levels (below 6.5): Can gradually corrode metal plumbing and fixtures.
• Alkaline levels (above 8.5): May result in a bitter taste and are often high in hardness as well.

Tannins

Tannins cause a yellowish coloration in water, often due to peaty soil and organic matter. They can pass through a softener and require specific media for effective removal.