A residential well water filtration system diagram is really a running order: the well pump, the pressure tank, then treatment stages arranged so each one gets the water it needs and protects the one behind it. The equipment on any two wells differs, but the sequence almost never does, and once you can read the order you can tell whether a quoted system is laid out correctly.
The fixed front end
Every diagram opens the same way: the submersible or jet pump, the pitless adapter or well head, a check valve, and the pressure tank with its pressure switch. Nothing on that list is treatment, and none of it should be moved to accommodate treatment. The point where the diagram becomes yours is immediately after the pressure tank, because that is the first place a treatment device can see full household pressure and a stable flow. Treatment placed before the pressure tank interferes with pump control.
Oxidation and contact come before removal
Where iron, manganese or hydrogen sulfide are present, something has to convert them from dissolved to solid before a filter can catch them. That is the air injection head, the ozone or peroxide feed, or the chlorine metering pump on the diagram, followed by a retention or contact tank where the reaction completes. This is the stage most often drawn in the wrong place. Put the filter first and it removes nothing, because the iron passing through it is still dissolved and invisible.
Sediment, then the specific media, then the softener
After contact comes particle removal: a spin-down or cartridge filter, then the media tank that targets the specific problem, an iron filter, a manganese medium, or a calcite neutralizer where the water is acidic. The softener comes after those, because oxidized iron fouls softener resin and a neutralizer raises hardness, so the softener needs to see the water in its final chemistry. Penn State Extension notes that softeners can take out dissolved iron within limits, but oxidized iron fouls resin, which is exactly why the order runs this way.
Disinfection and the point-of-use stage last
UV goes near the end, after everything that could shadow the lamp has been removed, and it feeds the house directly. A carbon filter sits ahead of the house too where chlorine was injected, to strip the residual. Finally the diagram shows a branch to the kitchen for a reverse osmosis unit, treating only the drinking tap. Bypass valves around each stage and sample ports between them are the details that make a diagram maintainable. Our well water filtration system guide walks the same order with equipment choices attached.
Questions people ask about residential well water filtration system diagram
Should the softener go before or after the iron filter?
After. Oxidized iron fouls softener resin, so iron is removed first and the softener sees water in its final chemistry.
Where does UV belong in the diagram?
Near the end, downstream of sediment, iron and manganese removal, because any particle or dissolved metal that clouds the water shields microorganisms from the lamp.
Can treatment equipment go before the pressure tank?
No. The pressure tank and switch control the pump, and treatment ahead of them interferes with pump cycling and sees unstable flow.
Why is there a tank between the injection pump and the filter?
That is the retention tank. Oxidation of iron and sulfide, and disinfection, both need contact time, and the filter can only remove what has already turned solid.