Treatment planner
What your water needs, in order
Enter what the lab reported and get the stages in the order they have to be plumbed, sized where the numbers allow, with the operating limit behind each one. Leave blank what was not measured; whatever cannot be decided without it is named rather than guessed.
Fill in what you have.
Iron, manganese, hardness and pH together settle most of it. pH matters more than its reputation suggests, because it decides whether the filter above it works at all.
The thresholds behind the plan
Some of these are federal standards. Others are equipment operating limits in general use, which is a weaker kind of claim, and they are marked so you can tell which is which.
| Threshold | Value | Basis |
|---|---|---|
| Iron, staining thresholdEPA secondary standard, set for staining and taste rather than health. | 0.3 ppm | Federal standardUS EPA |
| Manganese, staining thresholdEPA secondary standard. Black and grey staining begins around here. | 0.05 ppm | Federal standardUS EPA |
| pH, lower boundLower bound of the EPA secondary range. Below it, water is corrosive to copper and galvanised plumbing. | 6.5 pH | Federal standardUS EPA |
| pH, upper boundUpper bound of the EPA secondary range. | 8.5 pH | Federal standardUS EPA |
| Total dissolved solids | 500 ppm | Federal standardUS EPA |
| Nitrate, health standardEnforceable federal health standard. Infants under six months are the population at risk. | 10 ppm as N | Federal standardUS EPA |
| Arsenic, health standard10 parts per billion. | 0.01 ppm | Federal standardUS EPA |
| Manganese, health advisoryLifetime health advisory level rather than an enforceable standard. | 0.3 ppm | Government health agencyUS EPA |
| Hydrogen sulfide, ceiling for oxidising mediaAbove this, the answer moves to continuous chlorination or ozonation with filtration. | 6 ppm | Government health agencyMinnesota Department of Health |
| Hydrogen sulfide, ceiling for carbon | 1 ppm | Government health agencyMinnesota Department of Health |
| pH needed to oxidise ironRutgers Cooperative Extension states that where aeration is limited by a pressure system and pH is above 6.8, an oxidising filter can be an option. Oxidation speed collapses below it: 90% of iron oxidises in about 30 seconds at pH 8, an hour at pH 7 and roughly 100 hours at pH 6. | 6.8 pH | Government health agencyRutgers Cooperative Extension |
| pH needed to oxidise manganeseHigher than the figure for iron, and the media minimum is a manufacturer specification rather than a published standard. The gap itself is well sourced: North Dakota State University Extension puts the optimum pH for chlorine oxidation at about 8.0 for iron and 8.5 for manganese, and the National Drinking Water Clearinghouse notes that oxidation of manganese by oxygen alone is very slow below pH 9.5. | 7.5 pH | Engineering practice |
| Iron a softener can carry, cautious readingThe cautious reading. Above this, iron fouls standard resin and costs capacity permanently. | 1 ppm | Engineering practice |
| Iron a softener can carry, vendor claimUpper figure claimed for iron-tolerant or fine-mesh resin. A vendor claim, not a design basis. | 3 ppm | Engineering practice |
| Hardness worth softeningAbout 120 mg/L, where the USGS scale crosses from moderately hard into hard. | 7 gpg | Engineering practice |
| UV, maximum turbidity | 1 NTU | Engineering practice |
| UV, maximum iron | 0.3 ppm | Engineering practice |
| UV, maximum manganese | 0.05 ppm | Engineering practice |
| UV, maximum hardnessScale on the quartz sleeve blocks the light that does the work. | 7 gpg | Engineering practice |
Questions
- What if I do not have a water test yet?
- Leave the fields blank and fill in only what you know. The plan gets less specific as fields empty out, and it says which missing number is holding it back. A basic well panel covering iron, manganese, hardness, pH and bacteria is the usual starting point.
- Do my numbers get sent anywhere?
- No. The calculation runs in your browser. There is no server to send them to. Sharing a result puts the values in the link, so treat a shared link like the report itself.
- Why does the order of equipment matter so much?
- Each stage depends on the one before it. An oxidising filter needs a high enough pH to work at all, a softener lasts longer on iron-free water, and ultraviolet light needs water clear enough to pass through. Correct equipment installed in the wrong order underperforms and sometimes fails outright.
- Why does it sometimes refuse to answer?
- Because some water is outside what packaged residential equipment is built for. Very high iron, extreme hardness, a pH below 5 or a well that cannot supply enough flow to backwash a filter all need a system designed for the water rather than chosen from a catalogue.
Choosing between two options
Water softener vs iron filter: which your well needs
They are not alternatives. An iron filter oxidises and removes iron; a softener exchanges calcium and magnesium. Water with both problems needs both, in that order, and water with only one needs only one.
Air injection vs chemical injection
Air injection is the default and the right answer for most well iron. Chemical injection is for the specific cases air cannot reach: sulfide above about 6 ppm, very heavy iron, organic iron and iron bacteria.
UV vs chlorination for well water
UV where the water is clear and the contamination is at the source. Chlorination where the water is not clear, where the plumbing itself is suspect, or where iron and sulfide need oxidising anyway.