What Gets Filtered
It’s important to know what’s in your water that you want to filter out. Filter systems should remove, at a minimum, chlorine and sediment. After that, filter systems can remove chemicals, volatile organic compounds, scale, minerals and metals. How much a filter system removes can vary greatly between manufacturers and the type of filters yours includes.
While some systems work by simply removing sediment from your water, others are more comprehensive and can include UV light exposure or other means to destroy or otherwise eliminate microorganisms on a molecular level.
Degree of Filtration
The size of the impurities in water is measured in terms of microns. A micron rating is closely associated with a system’s filtration degree and identifies the purity level in treated water. Filter micron ratings indicate the largest size of particles that are allowed to pass through the filter. A filter designed to capture five-micron particles won’t allow larger particles to go through the filter, but will let particles smaller than that pass.
Pre-sediment filters trap sand, dust and large metal contaminants from water, typically down to around 50 microns. Finer filters that remove and trap 20-micron particles eliminate those elements down to a size in which you’ll begin to see cloudiness disappearing. Five-micron filtering will remove any particles visible to the naked eye and eliminate many bacterias, cysts and some organics, while one-micron and smaller purification methods create very pure water.
Filter Capacity
A filter’s capacity matters because it will determine how often you need to purchase a new filter. Filter capacity and lifespan can vary depending on how much water you use and the quality of water you’re filtering. Filters become ineffective once they fill up.
As a general rule, the finer the filter media, the more often you’ll need to swap filters for a fresh one. For instance, a five-micron filter will need replacement more often than a 20-micron one. However, frequent filter changing can be reduced in a multi-stage filtration system by starting with large-micron filtration and sequentially moving through finer filters.
Flow Rate
Home filtration systems tend to impact the flow rate in a home, or at least it’s a frequent complaint of homeowners who install them. The flow rate determines how much water can pass through the filter at one time. A five GPM filter is typically adequate for one to two people in a one or two-bathroom home.
Generally, the finer the filtration, the lower the flow rate. Meaning cleaner water requires more time to pass through the filtering system. Whole house filtration systems that provide a high water purity are often physically larger to increase the flow rate or can be accompanied by temporary filtered water storage.
| HOUSEHOLD SIZE | ONE TO TWO BATHROOMS (GPM) | THREE TO FOUR BATHROOMS (GPM) | FIVE TO SIX BATHROOMS (GPM) |
|---|---|---|---|
1 – 2 | 5 – 7 | 7 – 10 | 10 – 14 |
3 – 4 | 5 – 8 | 8 – 12 | 12 – 14 |
4 – 5 | 7 – 10 | 10 – 12 | 14 – 16 |
6 – 7 | 8 – 12 | 12 – 16 | 16 – 20 |
7 – 8 | 12 | 14 – 16 | 20 |
*GPM: gallons per minute
Operational Temperature and Pressure Range
Whole house water filtration systems can only operate if adequate water pressure is available. Typically these systems require a minimum of 20 pounds per square inch (PSI) to function. Higher filtration levels require higher pressures. Most municipal water systems deliver somewhere around 35 PSI of pressure. However, homes served by private wells may have to ensure their well pump can deliver adequate pressure.
Water temperature can also affect water filtration. However, most homeowners don’t have much to worry about. Optimal filtering is achievable in a wide range of temperatures between freezing and boiling. A filter system located outdoors should only be considered in climates that don’t experience freezing weather.
Installation
Most water filtration systems can be installed by yourself. However, some of the higher-end models will need professional installation. Anytime you’re dealing with water, you’ll want to make sure you know what you’re doing because any error can lead to catastrophic damage to your home. If you’re not comfortable installing a filtration system, call a pro.
Maintenance
Water filtration systems vary widely in their maintenance needs, and the manufacturer can supply information regarding what your particular system will require. Single-stage systems may only require infrequent filter changes on a regular schedule, while complex, multi-stage systems could require regular backwashing, cleaning, regeneration and other maintenance that you can perform or hire a professional to complete the work.
Whole House Filter System Warranties
Warranties on whole house filtration systems are highly variable between manufacturers, products, what they cover and for how long. Warranties of one year are just as common as lifetime warranties. A typical warranty covers manufacturing defects and component failures, but doesn’t cover installation issues or filter changes.
Filter Certification
The National Sanitation Foundation (NSF) tests and rates water filters and has developed requirements for safety and performance. The number signifies that the order, requirement or protocol was established, and not focused on the rating.
NSF certification ensures that your water filtration system meets rigorous safety and construction standards. An NSF-approved system has been tested to ensure that it removes the contaminants it claims to, and won’t allow specific pollutants to pass through.
