There are two effective methods for improving tap water: reverse osmosis and water softening. The softening method involves adding water softener to get rid of mineral in the water that affects the taste. Reverse osmosis purifies water by filtrating water and effectively removing organisms and chemicals. The method you use depends on different circumstances so it is worth knowing how each method works.
In the reverse osmosis method a membrane is used to separate the pure and unfiltered water. In normal conditions, osmosis pressure will push the water molecules to the side with unfiltered water to balance the concentration on either side. But reverse osmosis will pressurize the unfiltered side and water is forced towards the pure side.
The water softening method works on the process called ion exchange. The hard water passes over salt covered material that attracts minerals. The softener will absorb the mineral and sodium is released from the salt.
Reverse osmosis can remove a variety of water contaminants including nitrate, lead, sulfate, dissolved solids and sodium. The U.S. Environmental Protection Agency provides consumer information which states that most chemical contaminants and disease causing organisms can be removed by reverse osmosis. North Dakota State University suggests using the process in conjecture with additional filtering stages, like using activated carbon, which will effectively reduce levels of dioxins, volatile organic compound and pesticides.
Magnesium and calcium are effectively removed by water softener and it also decreases the level of manganese and iron. Other contaminant are not usually effected which makes it more practical to use the system with other filtration systems. It is a good method if you need to remove minerals from the already clean municipal water supplies.
Water that has passed through a softener unit will not contain calcium and magnesium and will instead contain sodium. Water hardness is measured as grains of dissolved minerals per gallon. According to the North Dakota State University, for every mineral grain that the softener removes, it adds sodium, about 8 parts per million, to the water. The website for Lenntech Water Treatment calculates this to be around 3% of the normal sodium intake of a person. You will need to consult a doctor before getting a water softener if you have any problem with a diet including sodium.
The output of a reverse osmosis system is purified water. There is no such thing as a perfect filtration solution, the contaminant traces that may remain will be related to the contaminants that was in the water before treatment.
A water softener would require the periodic replacement of salt. The salt solution, depending on what model you are using, will have to be recharged occasionally. The process involves opening the unit, turning valves and flushing out minerals that could have accumulated.
The membrane and the additional filters, both pre and post, will need to be replaced in a reverse osmosis unit depending on the amount of water the system has filtered.
Both the systems mentioned here work on water pressure and don’t require electricity. The reverse osmosis method uses three time the amount of water it produces during processing. The processing water is unpurified and is dumped into the sewer. Most household uses this method for drinking water lines since a large and costly system will be required to meet the household needs.