Test before you buy
City water and well water are different problems. If you are on city water, the utility publishes an annual water quality report that tells you what it treats for and what it found. If you are on a well, nobody tests it but you.
A test tells the plumber what to solve: hardness, iron, sulfur smell, chlorine taste, sediment or bacteria. Sizing a system without that is guessing, and the wrong system treats the wrong thing while you pay to maintain it.
What each device does
- Sediment filter
- Catches sand, grit and rust. First stage in most systems, and the cartridge is the one you change most often.
- Carbon filter
- Takes out chlorine taste and odor and some organics. Common at the whole house and under the sink.
- Water softener
- Exchanges hardness minerals for sodium or potassium. Fixes scale on fixtures and in the water heater. Needs salt and a drain.
- Reverse osmosis
- Point of use system under the sink for drinking and cooking water. Produces some waste water by design.
- Iron or sulfur treatment
- For well water with rust stains or a rotten egg smell. Sized by the test result, not by the symptom alone.
- UV disinfection
- Treats bacteria in well systems. Pairs with filtration, since it needs clear water to work.
Installation and upkeep
Whole house equipment goes in near the main, after the meter and before the branches, with a bypass so the house has water while the unit is serviced. Softeners and some filters need a drain line, which shapes where the unit can go.
Every system has a maintenance schedule: cartridges, salt, a resin bed, a UV lamp. Ask what each one costs per year and who does it. A system nobody services stops treating and starts restricting flow.
Common questions
Do I need a softener here?
That depends on your test result. Softeners solve hardness. If your issue is taste, odor or sediment, a filter is the answer and a softener is a cost with no benefit.
Will a filter fix a rotten egg smell?
Sometimes. Sulfur odor has more than one cause, and one of them is the anode rod inside the water heater rather than the supply. The plumber checks which it is before selling you equipment.
Can I keep the fridge and the ice maker on filtered water?
Yes, and it is worth planning at install time. Whole house treatment covers it already. With a point of use system, the line to the fridge has to be part of the design.
How often do cartridges get changed?
It depends on the cartridge and on how dirty the water is. The plumber gives you the interval for your system, and a pressure drop at the fixtures is the sign you are past it.
