Whole-house filtration is a category, not a product

What is whole house water filtration?

Whole-house filtration means treating water where it enters the building, so every tap, shower and appliance gets the same water. That is the point-of-entry approach, and it is the right choice when the problem affects your whole house - sediment, chlorine taste and smell reaching every shower, staining across all your fixtures. It is a poor choice when the problem only matters in the glass you drink from, because treating the water going to your toilets and your washing machine is expensive and pointless.

Signs you need whole house water filtration

• Grit or fine sediment collecting in aerators, toilet cisterns and the bottom of the kettle throughout the house
• A chlorine or chemical smell you notice most in the shower, not just at the kitchen tap
• Every fixture in the house shows the same discolouration or staining, not just one
• A well, a spring, or any private source where nothing filters the water before it reaches you
• You are protecting downstream equipment - a softener, a UV lamp, an on-demand water heater - from fines
• A lab result identified something present throughout the supply that you want addressed at every outlet
• Water pressure has fallen gradually across the whole house and existing filtration has never been changed

Seeing something not on this list? Browse water treatment problems by symptom →

How whole house water filtration actually works

1. 1

   Answer the real question first: whole house, or one tap?

   Point of entry treats everything. Point of use treats one outlet, usually the kitchen. If your concern is what you drink and cook with, point of use is cheaper, more effective per dollar, and easier to maintain. Point of entry earns its cost when showers, laundry, appliances or fixture staining are part of the complaint.

   Watch forBeing sold point of entry for a drinking-water concern. A whole-house system treats the water flushing your toilets to the same standard as the water in your glass, and you pay for all of it.

2. 2

   Let the test result choose the media

   This is the step that makes the whole thing work. Sediment, chlorine taste and odour, iron, hydrogen sulphide, acidity and specific contaminants each call for a different medium, and some of them are mutually incompatible in one vessel. Our water testing page covers getting a result nobody has a stake in.

   Watch forA quote that names a tank size and a price but never names the media, or that says "multi-stage" without saying what the stages are. That is a box, not a design.

3. 3

   Put a sediment pre-filter in front of everything

   Almost every whole-house design starts with sediment removal, because fines shorten the life of everything behind them - carbon beds, softener resin, UV sleeves, cartridge elements. It is the cheapest component and the one that protects the expensive ones.

   Watch forA pre-filter fitted somewhere you cannot reach with a wrench and a bucket. You will be changing it far more often than anything else in the train, and an inaccessible one is a pre-filter that gets left in until it blocks.

4. 4

   Size for peak flow, not for house size

   A filter has to pass the maximum flow your house can draw - two showers and a washing machine at once - without strangling it. Media beds have a service flow rate they work at and a higher rate at which water simply channels past the media without being treated properly.

   Watch forSizing from bedrooms or square footage. The number that matters is simultaneous demand. An undersized whole-house filter announces itself the first time somebody flushes while you are in the shower.

5. 5

   Budget for pressure drop, and measure it

   Every filter costs you some pressure, and that cost grows as the medium loads up. A correctly specified system starts with a small drop and gives you a way to see it grow - gauges before and after the filter are inexpensive and turn a guessing game into a reading.

   Watch forNo gauges. Without them the first symptom of a blocked filter is bad showers, and by then you have been running degraded for weeks. Ask for gauges either side; it is a small line item.

6. 6

   Decide between cartridges and a backwashing tank

   Cartridge housings are cheap to install and you replace an element periodically. Backwashing media tanks hold far more medium, clean themselves on a cycle, and need a drain and usually power - which puts them in the same siting conversation as a softener.

   Watch forA backwashing unit specified where there is no compliant drain within reach. The backwash has to go somewhere, and improvising that connection is the same cross-connection problem softeners have.

7. 7

   Sequence it correctly with everything else

   Order matters. Sediment goes first. Anything that removes iron or oxidises goes ahead of a softener so the resin is protected. Disinfection goes last, because it needs clear water to work through. Get the order wrong and each stage undermines the next.

   Watch forA system added to an existing train without anyone reconsidering the sequence. New equipment bolted on the end of an old setup is how a perfectly good softener ends up doing a job it was never protected for.

8. 8

   Log the media life and actually replace it

   Carbon in particular has a finite capacity, and a spent carbon bed does not warn you - the water simply stops being treated while the equipment continues to look exactly the same. Write the install date and the expected replacement date on the tank itself.

   Watch forTreating a filter as installed-and-done. Media that is long past its life is worse than no filter, because it is providing false reassurance and, on a neglected cartridge, somewhere for biofilm to grow.

What does whole house water filtration cost?

Whole-house filtration ranges from a few hundred dollars for a single sediment cartridge housing to several thousand installed for a multi-stage backwashing system with specialist media. The media choice drives the price far more than the tank does. Ongoing costs are cartridges and periodic media replacement - ask for both in the quote.

See the full whole house water filtration cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →