How Home Water Filters Work

by | Feb 12, 2016 | Blog, Plumbing | 0 comments

How whole-home water filtration worksWater cleanliness and contamination levels have been in the news quite a bit recently.  And, while the municipal water system is fairly clean across most of the US, it never hurts to make sure you’re getting the cleanest water available.

What Does a Filter Do?

Just like your home’s air filter, a water filter removes contaminants, particles, and other material from your water so you’re left with clean water that’s as pure as possible.  Just like with air filters, not every filter works as well as another.  They’re also affected by location within your home’s plumbing.

Water filtering system. Making clear potable water

Water filtering system. Making clear potable water

Removing contaminants from water is achieved by passing water through a filter and allowing those particles to collect on the filter itself.  This can be done by cation exchange (as is the case for water softeners), by increasing the surface area of the filter on a microscopic level (carbon filters), or through use a super-permeable membrane (reverse-osmosis).

All of these filters work, with varying degrees of success based on contaminant type, but if you put them in the wrong place you may find yourself not helping at all.  If your home uses older plumbing, mineral buildup, pipe degradation, and other problems can leave contaminants in your water.  Simply placing a whole-home filter at the point of entry won’t protect your water against the contaminants from your home’s pipes.  You could replace all the plumbing in your home, or you could install filters at the tap.  Faucet filters are effective for many, but not all, contaminants so they’re great for removing problems picked up in the “last mile” of water-flow.  That is, they’re good for clearing out minerals and particles left from your own home’s plumbing system.  For removing the smallest particles, or issues with your city’s water supply, a whole-home filter system is the way to go.

Types of Filters

Activated Carbon Filters – Positively charged, absorbent carbon.  Carbon filters remove the majority of pollutants from home water and can even be installed directly into the faucet.  Unfortunately, perchlorates are not removed by a standard carbon filter.  The important thing is that carbon filters will remove pollutants and heavy metals from your water.

Distiller – Rather than passing water through a substance to trap contaminants, a distiller boils the water and condenses the steam to be used as water in the home.  The heat from the boiler kills off most bacteria, and the steam itself leaves behind the majority of heavy metals and pollutants.  Unfortunately, a distiller takes a great deal of energy to heat water, so it’s not as energy-efficient as other methods.  The machinery used is also fairly large, so it requires a whole-home system or a countertop unit.

Ultraviolet Disinfection – A strong UV beam shines on the water as it passes through this contactless-filter.  The UV light sterilizes the water, removing harmful bacteria and living organisms.  It’s best to pair this filter with a carbon filter at the tap in order to filter out physical material as well, since the UV light will have no effect on heavy metals.

Reverse-Osmosis – Of course, RO filters are possibly the most commonly known type of filter.  They work well in combination with carbon or UV filters and fit beneath the sink or can be attached to your home’s overall water system.  A semipermeable membrane allows only water to pass through to the other side by taking advantage of the osmotic process of the membrane (where water will pass through to equal out dilution levels, leaving impurities behind).  The one drawback to this system is that it generates a great deal of unused water which is sent back through the water system.

Any of these filters will help to improve the quality of water in your home, but picking the right filter for your needs is key.  If you live an area with foul tasting water, a whole-home system will remove contaminants from all faucets in the home.  If it’s just a problem with your home’s plumbing, have a filter installed at the faucet. The best results will come with a full system at all points for the clearest, cleanest water you’ve ever tasted.


If you need any assistance with installation or repair of your water filter (or any plumbing fixture or appliance), don’t hesitate to contact the experts at Boulden Brothers plumbing!

Give us a call at (302) 368-3848 for any of your Delaware, Maryland, and Pennsylvania home service needs — plumbing, electrical, HVAC, propane, and more!

Call us 24 hours a day, 7 days a week to answer any questions you might have.

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