types of water

The Different Types of Water


The Different Types of Water

The key to using our water resources in the most efficient manner is to understand the different types of water. There are certain properties of the different types of water which make some types more suitable than other for some applications.

Potable Drinking Water

This is the water which comes out of our faucets, sinks and bathtubs. The safety of our water is protected by the Clean Water Act which regulates discharges of pollution which could wind up in the nation drinking supply. The Safe Water Drinking act defines the six groups of contaminants to be tested for in the water as well as their maximum control limit which the maximum amount of the contaminant in question before action must be taken to rectify.


Over 70% percent of the earth’s water is tied up in its oceans as sea water. Most scientists agree the ocean was formed over millions and millions of years from the continual ‘degassing’ of the Earth’s interior. Water remained a gas until the Earth cooled below 212 degrees Fahrenheit then the water vapor condensed into rain which filled the basins that are now our oceans. The characteristics of seawater are due both to the nature of pure water and to the materials, i.e. the salt dissolved in the water. The salt concentration of sea water averages about 35,000 ppm or 3.5% concentration by mass. The salt in the water typically believed to be only sodium and chlorine ion but other ions including magnesium, potassium and calcium.   Ocean water is not drinkable because of its high salt content. Brackish water is water which had too much salt to be considered potable but contains less salt than typically found in the ocean. Potable water is considered to have salt content below 1000 mg/l or one percent salt by mass.

Recycled (Reclaimed) Water

Recycled is waste water which is treated to a level less than normal drinking water standards, used in non-potable applications such as irrigation. The processes are which produce reclaimed water and potable water are very similar.  Reclaimed drinking water does not undergo tertiary processes to make the water drinkable. Recycled water is much cheaper and there are no sewer charges in many commercial applications.


Rainwater is formed by the evaporation of water into the air. Once the vapor interacts with dust particles in the atmosphere these coalesce into droplets which will return to the earth as rain when they become heavy enough. Rain water has lower dissolved solids levels and a lower pH than other types of water because of the carbon dioxide and sulfur dioxide in the air which form carbonic acid and sulfuric acid respectively.

Grey water

Grey water is the water which is generated from the laundry, sinks and tube, it can be defined as water other than toilet water which is suitable for non-drinking applications. Grey water comprises higher dissolved solids than potable water and contains added dissolved phosphates and nitrogen. Additionally, bacteria are present from what is washed from our bodies along with minor amount of food particles. The exact components will be dependent on the amount of grey water produced by laundry, shower/bathing, kitchen use.

Note: brown water is generated from our toilets needs to be treated at a waste water treatment plant before being reused in any application

Storm water

Stormwater runoff is water from rain or melting snow that “runs off” across the paving and road surfaces instead of seeping into the ground. The water can pick up and carry many substances that pollute water. This pollution winds up in streams, lakes and other water bodies. Some pollutants such as pesticides or fertilizers are harmful in any quantity while others such as sediments from bare soil or agricultural land can harm creeks, rivers and lakes in sufficient quantities.

The importance of understanding the properties of the various types of water cannot be understated. This knowledge will be crucial if we are to understand how we can use the water we need more efficiently.