How Clean is Your Water?

Just because water comes from the tap or in a bottle, does that necessarily mean it's clean?

No. Water purity varies greatly depending on the source and whether it's a purified, distilled, spring, mineral, artesian, or some other type of water. But how is water purity measured?

Water purity and quality are directly related to the amount of Total Dissolved Solids (TDS) found in the water. This includes anything present in water other than the pure water (H20) molecule such as suspended solids like minerals, salts, or metals. TDS is expressed in units of milligrams per unit volume of water (mg/L), also referred to as parts per million (ppm).
Dissolved Solids can come from 3 different sources 1) organic, 2) inorganic and 3) metals.

1. Some dissolved solids come from organic sources such as leaves, silt, plankton, and industrial waste and sewage. Other sources come from runoff from urban areas, road salts used on street during the winter, and fertilizers and pesticides used on lawns and farms.

2. Dissolved solids also come from inorganic materials such as rocks and air that may contain calcium bicarbonate, nitrogen, iron phosphorous, sulfur, and other minerals. Many of these materials form salts, which are compounds that contain both a metal and a nonmetal. Salts usually dissolve in water forming ions. Ions are particles that have a positive or negative charge.

3. Water may also pick up metals such as lead or copper as they travel through pipes used to distribute water to consumers.

The EPA Secondary Regulations advise a maximum contamination level (MCL) of 500mg/liter (500 parts per million (ppm)) of total dissolved solids for safe drinking water. Numerous water supplies exceed this level. When TDS levels exceed 1000mg/L it is generally considered unfit for human consumption. A high level of TDS is an indicator of potential concerns, and warrants further investigation. Most often, high levels of TDS are caused by the presence of potassium, chlorides and sodium. These ions have little or no short-term effects, but toxic ions (lead arsenic, cadmium, nitrate and others) may also be dissolved in the water.