· Michael Blair
Whole-house and point-of-use systems solve different problems. Choosing between them starts with what you are actually trying to fix.
What whole-house is for
Problems affecting every fixture: sediment, chlorine odour in the shower, and anything that damages plumbing or appliances. Softening is inherently whole-house.
It treats a large volume, so cartridges are larger and replacement intervals longer, and installation involves the main line.
What point-of-use is for
Drinking and cooking water. An under-sink carbon block or reverse osmosis system treats the small volume you actually consume, to a much higher standard, for far less money.
Reverse osmosis in particular is impractical whole-house because it wastes water and produces slowly.
- Sediment, chlorine odour, appliance protection: whole-house
- Drinking and cooking quality: point-of-use
- Reverse osmosis: under sink only, not whole house
- Softening: whole-house by nature
- Many houses want a sediment filter plus an under-sink unit
The common sensible combination
A whole-house sediment filter and carbon for chlorine, a softener if hardness justifies it, and an under-sink unit for drinking water.
That covers appliance protection, shower and laundry quality, and drinking water without paying to purify water used to flush toilets.
Maintenance is the deciding factor
Every system has cartridges with a replacement interval, and a neglected filter is worse than none — it becomes a restriction and a place for bacteria.
Choose a system you will actually maintain. Under-sink cartridges are easy; a whole-house housing in a crawl space gets forgotten.