The drinking water that is supplied to our homes comes either from surface water or ground water. Surface water gets collected in streams, rivers, lakes, and reservoirs whereas ground water gets collected in pores and spaces within rocks and underground aquifers. We obtain ground water by drilling wells and pumping it to the surface.

Public water systems provide surface water and ground water. Water treatment systems are either government or privately-held facilities. Surface water systems withdraw water from the source, treat it, and deliver it to our homes whereas ground water systems withdraw and deliver water, but they do not always treat it.
Contaminants can be Inorganic, Organic, Biological, or Radiological substance or matter in water.
Inorganic: Inorganic contaminants include the minerals and toxic metals. Some of these contaminants like calcium and magnesium are naturally occurring. Other contaminants like copper and lead usually get into the water through pipes. Contaminants such as lead and arsenic can be quite dangerous and hence the water needs to be treated.
Radioactive: Radioactive contaminants are chemical elements with an unbalanced number of protons and neutrons resulting in unstable atoms that can emit ionizing radiation. Examples of radiological contaminants include cesium, plutonium and uranium.
Organic: Organic contaminants are carbon-based, which means they are derived from petroleum. Since they are carbon-based, they can easily bind with human tissue which can make them extremely toxic in very tiny quantities.
Biological: Biological contaminants are also referred to as microbes or microbiological contaminants. Examples of biological or microbial contaminants include bacteria, viruses, protozoan, and parasites.
There are many sources that lead to water contamination. Some of the most common sources that lead to water contamination are:
Naturally occurring chemicals and minerals (for example: arsenic, radon, uranium)
Local land use practices (for example: fertilizers, pesticides, livestock, concentrated animal feeding operations)
Manufacturing processes
Sewer overflows
Malfunctioning wastewater treatment systems (for example: nearby septic systems)
The presence of certain contaminants in our water can lead to health issues, including gastrointestinal illness, reproductive problems, and neurological disorders. Infants, young children, pregnant women, the elderly, and immunocompromised persons may be especially at risk after drinking contaminated water. For example, elevated levels of lead can cause serious health problems, especially for pregnant women and young children.
Cities are in a desperate need of replacement from old age and wear. Water contamination can occur at almost any point in the delivery channel including lead leaching from corroded pipe solder, bacteria entering the system from water main breaks, or gardening chemicals back-siphoned from a careless neighbor.

To make matters worse, most cities also add chemicals like chlorine and fluoride to their water. The water quality in India is most likely to decline in the coming years. The best way to protect your family from the increasingly wide range of contaminants found in today's tap water is by installing a reverse osmosis water system.
The most common hardness causing minerals are calcium and magnesium that is dissolved in water. Hard water is the most common problem faced by a lot of people these days. Hard water spots your glasses and dishes, makes laundry dull, and causes soap scum and scale to build-up making cleaning a chore.
Term Grains per Gallon (gpg) ppm (mg/L)
Soft 1.0 17.0
Slightly Hard 1.0-3.5 17.1-60
Moderately Hard 3.5-7.0 60-120
Hard 7.0-10.5 120-180
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RO is the most convenient and effective method of water filtration. Reverse osmosis is the process by which water molecules are forced through a semi-permeable membrane under pressure. The membrane in a RO System filters out any impurities smaller than one micron.

Non-RO water filters typically use a single activated carbon cartridge to treat water. They are less effective, and the pore size on these filter media are much bigger, generally 0.5 - 10 micron. They can filter out coarse particles, sediments and elements only up to their micron rating. Anything finer and most dissolved substances cannot be filtered out. As a result, water is safe enough to be consumed.
RO systems typically filter water using the following steps:
Tap water flows through a sediment filter to remove dirt, rust and other solid objects.
The water then flows into a carbon filter which removes 98% of the chlorine and organic chemicals.
The next stop is the reverse osmosis membrane which separates up to 99% of the dissolved contaminants from the water molecules. These removed impurities are rinsed down the drain leaving behind only safe water.
This water is stored in a reservoir tank, and is accessed through a faucet.
The final step involves pushing water through a carbon block polishing filter to enhance the taste & odor.

Reverse osmosis removes more contaminants than other carbon, faucet or pitcher systems. RO systems can remove nitrates, sodium, and other dissolved inorganic and organic compounds that other systems can miss.
To determine which RO system you need, you will first need to consider the input water pressure at your home. Table below for reference:
If Your Water Pressure Recommended Model
Is Normal
(40-85 psi)
Stella, Prisma, Majesto & Edge
Most people who use the municipal city tap water fall in this category.
If Your Water Pressure Recommended Model
Is Lower
(30-50 psi)
Prisma, Edge & Majesto
You are likely on a private well or municipal water with lower water pressure.

Many RO suppliers do not always provide enough technical information to help customers choose the right system for their homes. As a result, these customers are often surprised by problems like:
Common Problem Cause
Why is there no water in the tank? Not enough input water pressure for the system to work
Why is it taking all day for the tank to fill? Using a model with inappropriate GPD output
Yes, Reverse Osmosis Systems remove about 97% of the total dissolved solids (TDS) from your water, including salt and sodium. When you read the labels on any bottled water, you will discover that reverse osmosis is the same process which is being used by most bottled water manufacturers, so in effect you're really getting bottled water without any hassle.
Here are some helpful considerations you may want to take into account before purchasing a water treatment system:
How hard is your water?
Having your water tested will help you determine your exact needs, even though you may already know you have one or more water problems. In determining your water treatment needs, a water expert will look at a number of things. For example, the hardness level of the water and the size of your family will influence the size and type of equipment.
How much water you consume on a daily basis and what is the input water pressure?
The amount of water consumed and the water pressure are factors to consider while selecting a water purifier for your home. Household size may influence consumption, but different families all have different needs. Every factor should be considered, including family growth and guest visits.