Natural water we get in our homes for domestic use comes from lakes and rivers, which is not potable. To make it safe for drinking you need to purify it. Boiling the water is the best and the easiest way. Ten minutes of steady boiling will kill the germs it might contain. If water contains bits of sediments, then you must strain the water. You may use a piece of clean cloth for straining. This method of purifying the water is most suitable if you are out in the wild. You have no option, but to drink untreated water straight out a river or a lake.
If you do not have the means to start a fire, then place water out in the sun in a clean container. Sun rays would kill bacteria and thus water would be safe for drinking.
If you happen to be out in the wild, then you must carry with you 'water purification tablets'. These tablets usually are the part of survival kit.
In earlier times, there used to be no water filters and water purifiers. Those days boiling used to be the only method for making water safe for drinking. If you will drink boiled water you will find a significant change its taste. Aerating the water by pouring it back and forth between two containers does improve the taste. Besides, boiling water can be expensive because you would use fuel and that would add to cost of purifying the water.
If you use Purification tablets to treat water, then water would taste bitter. It is because these tablets have iodine. Besides, some types of protozoa do not die with chemical treatment. Iodine is harmful for people suffering from thyroid. It is harmful for pregnant women as well.
Water we get for domestic use is from lakes and rivers; and though it is treated chemically, exposure contaminates it again. Drinking such water can cause illness. It might taste fine, but it may contain organisms that can cause nausea, loss of appetite, diarrhea, fatigue and even vomiting. The diseases such as botulism, cholera and dysentery are caused due to drinking contaminated water. Some illnesses only cause discomfort; but others could be deadly. The usual symptoms are rashes on the body, muscle aches, fever, chills, and coughs.
In view of the facts mentioned above Water Filter or Water Purifier has become an everyday essential for every home. The advantage of water filter or water purifier is that it needs no fuel to boil the water. It does not use chemicals. It does not adversely affect the water flavor and does not leave in the mouth a bad lingering taste.
Water filters or water purifiers do not kill organism present in the water, but it simply traps them. Once caught in the filter we are saved from ingesting disease causing organisms.
To capture the organisms the water filters have millions of pores. The size of these pores is in microns. One micron is equals 1/1000 of a millimeter. Effectiveness of these filters and purifiers depends upon its ability to prevent ingress of parasite's eggs and its larvae. The pore size must be less than 0.4 microns.
Effectiveness of water filter depends upon its pore size efficiency. Almost all water filters work on the same principle. Only the method to pass water through the filter is different. In some "Water filters' water enters manually. Some have a freestanding filter. In some purifiers and filters the water is passed through suction. The portion where the clean water accumulates is called the filter outlet. All good 'water filters' comes with a pre-filter and a main filter.
Your personal need determines the kind of water filter you need. Water filters come in all sizes. There are 'water filters' available for campers. You get water filter that fits into your backpack.
A water filter with a flow rate of one liter per minute is good enough for home use.
Every water filter after it has filtered about 100 gallons of water should be changed. Frequent cleaning of filters is important because those organisms are not getting killed, but they are simply trapped within the filters. It is necessary to clean them under running water or through use a pump that comes with the water filter or purifier.
If water filter at any time is not in use, then flush the filters with a dilute bleach solution and let it dry. This will not allow bacteria to grow inside the filters.