There are several reasons for filtering water in your home. You may simply want to improve the taste of the water or you may need to remove unhealthy contaminants. The benefits don't stop with drinking water. Water filters can benefit cooking, protect your appliances and improve the water you use to shower. This guide explains different types of home water filters and gives you information to choose the best system for your home.
These is a wide variety of contaminants that may show up in water. Below are some examples.
Tastes and odors may not be harmful, but can be unpleasant.
Rust particles and other sediment can settle out of drinking water, clog sink aerators and affect appliances such as ice makers and washing machines. The condition where water has enough sediment and particles to be cloudy is known as turbidity.
Bacteria and parasites can be health concerns, particularly for the young, the elderly and anyone with weak immune systems. While well water is more likely to be contaminated by bacteria and parasites, the cysts Cryptosporidium and Giardia have been known to contaminate even chlorinated municipal water.
Lead can be present in water. Houses built before 1986 may have pipes joined with lead solder. Some municipal water systems may be composed of components that contain lead. Lead contained in water is tasteless and odorless, but should be avoided as much as possible. You can find filters that reduce it, but if you're concerned about the possibility of lead in your water, have it tested by a professional.
There are other potential contaminants — including pharmaceuticals, heavy metals and viruses — that might be present. Before you choose your water filter, learn what's in your water and determine what you want to remove. Most public water suppliers — such as cities or other municipalities — must publish an annual water quality report (known as a Consumer Confidence Report, or CCR). If you want specifics on the water coming from you tap and not just the general water supply, have the water in your home tested. You can purchase Water Test Kits, just make sure you understand what they test for. If your water comes from a well, you'll need to get the water tested to find out what contaminants it contains.
Water filters aren't effective against clear-water iron, which can leave red stains in tubs and toilets. A water softener can help reduce clear-water iron.
Pay attention to exactly what contaminants a water filter is designed to reduce or remove. Look for NSF certification, which indicates the filter has been independently tested to verify, among other things, that it reduces the contaminants it claims to reduce. Different water filter systems are certified to different standards. Some are certified to simply reduce contaminants that affect taste and smell, while others are certified to reduce contaminants related to health.
Consider the amount of filtered water you need and what you want to filter (water for drinking, cooking, bathing, etc.). You can find containers that filter a few cups at a time for drinking, devices that filter kitchen tap water for drinking and cooking, and whole-house water filtration systems that filter all the water coming into your home.
Many water filters are designed to filter cold water only.
Check the filter manufacturer's information for compatible faucet types.
You must maintain the water filtration system correctly for it to be effective. This includes changing filters at the recommended times. Many water filtration systems notify you when it's time to change the filter. Pay attention to filter life, measured in gallons filtered or months used and consider ongoing cost of replacement.
Particulate filters reduce sediment such as rust particles, dirt and sand. Multi-stage systems often use these as a first stage to keep the particles out of other filters.
Activated carbon filters reduce certain contaminants by chemically bonding with them. These are a common filter types for addressing tastes and odors caused by chlorine. Some activated carbon filters also reduce other contaminants such as lead and mercury.
Reverse osmosis (RO) filtration forces water through a membrane, collecting contaminants larger than the water molecules. While reverse osmosis doesn't remove chlorine, it reduces other contaminants that carbon filters cannot. Reverse osmosis systems generate several gallons of waste water for every gallon they filter. They can also remove beneficial minerals in addition to contaminants, so some systems are designed to restore these minerals to the water. Reverse osmosis can reduce contaminants such as lead, bacteria, parasites and viruses.
Ion-exchange filtration replaces contaminants ions with additives that are more acceptable. Water softeners use this process to treat hard water, exchanging magnesium and calcium for sodium. Ion exchange also reduces containments such as cadmium, copper and zinc.
Oxidation reduction (redox) filtration converts contaminant molecules — such as those of chlorine — into different molecules that lack the negative effects. This filtration method can reduce things such as chlorine, lead and bacteria.
Ultraviolet (UV) filtration uses UV light to remove some bacteria, viruses and cysts. UV filtration does not remove chemicals.
You may see micron measurements on some filter packaging, indicating the size of the pores the filter. A lower micron number indicates the filter has smaller pores designed to catch smaller contaminants.
When using a water filter in conjunction with a water softener, pay attention to the manufacturer's recommendations for the order of installation. Some water systems need the filter installed first-in-line, others need the water softener first-in-line.