The short version: nobody is testing your water but you. EPA does not regulate private wells, so the first purchase is not equipment — it is a laboratory test. Test for total coliform bacteria, nitrate, total dissolved solids and pH, then buy against the results. Treating a well without a test is how people end up with a carbon filter installed against a bacteriological problem it cannot touch.
The short answer
Step one, always: an annual lab test. EPA's own recommendation is to "test your private well annually for total coliform bacteria, nitrates, total dissolved solids, and pH levels."
Iron or manganese staining: Compact Whole House Water Filter, Metal Removal, From $217.67.
Nitrate, arsenic or high TDS in the results: reverse osmosis at the tap you drink from — Brondell H2O+ Capella RC250, $269.99.
Off-grid or no pressurised supply: The Water Machine off-grid solution, $999.99, which is gravity-fed and needs no power.
The single most important fact about your well
EPA states it without hedging: "The quality and safety of drinking water from private domestic wells are not regulated by the Federal Government under the Safe Drinking Water Act nor by most state governments and laws." And, directly: "Private well owners are responsible for delivering safe drinking water to their households."
That is a genuine difference in kind from municipal supply, not a technicality. A utility is legally obliged to test on a schedule, to meet enforceable maximum contaminant levels, and to notify you when it fails. Your well has none of that apparatus. There is no annual report, no compliance record, and no one who will call you if something changes.
On a well, the water quality report is the one you commission. There is no other.
This is also why our free ZIP water report will not help you. It pulls a utility's federal EPA compliance record. If you are on a well, there is no such record to pull, and we would rather tell you that than have you run it and conclude your water is fine.
What to test for, and what the numbers mean
EPA's baseline recommendation is four tests annually: total coliform bacteria, nitrates, total dissolved solids, and pH. Add tests for anything your region is known for — a local health department or state environmental agency can tell you what that is, and is worth one phone call.
| Test | The number to compare against | What it indicates |
|---|---|---|
| Total coliform bacteria | EPA MCL: no more than 5.0% of samples positive | A pathway between the surface and your well. This is a well-integrity problem before it is a filtration problem. |
| Nitrate (as nitrogen) | EPA MCL: 10 mg/L | Agricultural runoff, septic influence. Nitrate is dissolved; sediment and carbon filters do not touch it. |
| Nitrite (as nitrogen) | EPA MCL: 1 mg/L | Usually tested alongside nitrate. |
| Total dissolved solids | EPA secondary standard: 500 mg/L | Aesthetic guidance, not enforceable. A high number is a useful general signal that something is dissolved in quantity. |
| pH | EPA secondary standard: 6.5–8.5 | Outside that band, water becomes more aggressive toward plumbing — which can itself mobilise metals. |
| Arsenic | EPA MCL: 0.010 mg/L | Geological, region-dependent. Invisible and tasteless; testing is the only way to know. |
| Lead | EPA action level: 0.015 mg/L | Usually plumbing rather than groundwater. Note this level drops to 0.010 mg/L on 1 November 2027. |
| Iron | EPA secondary standard: 0.3 mg/L | Orange-brown staining on fixtures and laundry. |
| Manganese | EPA secondary standard: 0.05 mg/L | Black or dark staining; often found with iron. |
| Uranium | EPA MCL: 30 µg/L | Geological and region-specific. Worth testing once if your area is known for it. |
Matching equipment to results
The reason the test comes first is that these are four unrelated problems with four unrelated solutions, and the wrong one installed confidently does nothing at all.
Bacteriological results
A positive coliform result is not primarily a filter problem. It means something is getting into the well — a failed cap, a cracked casing, surface water intrusion, septic proximity. Fix the well first. Disinfection equipment treats the symptom, and we will say plainly that we do not currently sell a purchasable ultraviolet unit. If UV disinfection is what your results call for, that is a conversation to have with a local well contractor, and we would rather tell you that than sell you something adjacent.
Iron, manganese and sulphide
This is the classic well signature: orange staining in the sink, black speckling in the toilet tank, a rotten-egg smell at the hot tap. These are oxidisable metals and dissolved gas, and they are handled at the point of entry, before the water reaches anything.
- Compact Whole House Water Filter | Metal Removal (2-4 GPM | 1-2 people) — From $217.67, rated 4 GPM with a 1/2" inlet, sized for one to two people.
- Big Blue Whole House Water Filter | Metal Removal (4-6 GPM | 1-2 people) — From $435.36, rated 6 GPM, the larger-housing version of the same idea.
- Iron Filter Cartridge — From $49.00, the CQE-RC-04010 cartridge rated 5 GPM, if you already have a housing and only need the media.
Nitrate, arsenic and dissolved solids
These are membrane problems. Sediment filtration and carbon do not remove them, and no amount of stage count changes that. Reverse osmosis is the technology, and NSF/ANSI 58 — the standard covering reverse osmosis drinking water treatment systems — lists arsenic reduction, nitrate/nitrite reduction and fluoride reduction among the optional claims it tests, with TDS reduction as the one required claim.
Because RO is a point-of-use technology in this context, you treat the tap you drink and cook from rather than the whole house. The Brondell H2O+ Capella RC250 at $269.99 holds NSF/ANSI 42, 53, 58, 401 and 372 — the broadest certification set in our catalog. The Circle RC100 at $449.99 holds 42, 53, 58 and 372.
Sediment
Wells produce grit, and grit destroys everything downstream. A 5-micron sediment stage ahead of anything else is cheap insurance; the Waterdrop WHF21-PG at $165.99 pairs a 5-micron polypropylene sediment stage with an activated carbon block.
The order things go in
Treatment trains have a sequence, and getting it wrong wastes media:
- Sediment first. Everything downstream lasts longer.
- Iron and manganese next. Dissolved metals foul resin beds and blind membranes, so they come out before either.
- Softening, if hardness warrants it. Above 121 mg/L as calcium carbonate on the USGS scale, which is worth reading about separately in the hardness article.
- Point-of-use RO last, at the kitchen tap, for the dissolved contaminants that only a membrane addresses.
Off-grid and low-pressure situations
Every system above assumes pressurised plumbing. If you have a cabin, a seasonal property, or a well with no pressure tank, none of it applies. The Water Machine off-grid solution at $999.99 is gravity-fed — no pressure, no power, no drain connection. It is a two-stage arrangement of ceramic and carbon elements, and it ships free nationwide including Alaska, Hawaii and Puerto Rico, which for a remote property is not a trivial detail.
It is a different category of product and we are not going to pretend it is equivalent to a plumbed treatment train. It is the answer when there is no plumbing to treat.
Maintenance, and what happens if you skip it
| Item | Interval | If you skip it |
|---|---|---|
| Laboratory test | Annually, per EPA | You are treating last year's water. Well chemistry changes with rainfall, land use and seasons. |
| Sediment cartridge | When pressure drops | Flow falls across the whole house, and everything downstream works harder. |
| Replacement WD-WF10-FG for Whole House 2-Stage Filter WD-WHF21-FG – Reduces Iron & Manganese | 6–12 months, $71.99 | Iron-reduction media exhausts. Staining returns, usually before you notice the filter is spent. |
| RO membrane | 24 months on most systems | Reduction performance falls off quietly. There is no alarm and no taste change. |
Test after any change, too, not only on the calendar. EPA specifically calls out testing when there are known groundwater problems in the area, when something changes near the well, after repairs to the system, and whenever the water itself changes in taste, smell or appearance.
Questions people actually ask
My water looks and tastes fine. Do I still need to test?
Yes. Nitrate, arsenic and uranium are all colourless, odourless and tasteless at the levels EPA regulates them. Clarity tells you about suspended solids and nothing about dissolved ones.
Can one system handle everything?
Not usually, and the honest version of this answer is that "all-in-one" well systems are generally a sediment and carbon combination with a broad description. Iron removal, softening and membrane filtration are different processes with different media and different failure modes. A train of two or three correctly chosen stages beats one unit that claims everything.
Is a whole-house filter enough, or do I need RO too?
It depends entirely on what the test found. Whole-house handles what affects every tap — sediment, iron, chlorine, odour. Point-of-use RO handles what is dissolved and matters only in what you drink. For a well with nitrate or arsenic, you want both, for different reasons. The whole-house versus point-of-use article works through that split properly.
How often should the well itself be inspected?
Separately from water testing, the physical well — cap, casing, seal, surrounding grade — is what keeps surface water out. A positive coliform result is usually telling you about that rather than about your filtration.
Does hard water on a well need different treatment than city water?
The softening process is the same. What differs is that a well often carries iron alongside hardness, and iron fouls softener resin, so the order of operations matters more than it does on treated municipal water.
Where to start
Get the test. Then browse well water systems and whole-home filtration against your actual results, or send us the report and we will read it with you. We would rather size something correctly from a page of numbers than sell you a system that turns out to be aimed at the wrong problem.
Regulatory figures are U.S. EPA National Primary Drinking Water Regulations (enforceable maximum contaminant levels and treatment-technique action levels) and EPA Secondary Drinking Water Standards, which EPA does not enforce and publishes as aesthetic guidance. Hardness ranges are the U.S. Geological Survey classification. Certification references name the NSF/ANSI standard and its scope; a system is described as certified only where that certification is recorded on its own product page. Prices were read from this store on the day of publication and change. This article is general information about equipment, not a diagnosis of your water and not medical or health advice.