Water Test Results Interpreter
Enter your water test numbers below. We'll color-code each parameter and recommend treatments in priority order. All inputs are optional: fill in what your test report covers, and results update live.
Hardness & Minerals
Chemistry
Red Flags
How to Read Your Water Test Report
A standard water test report lists measured concentrations for several parameters. Here is what each one means in practical terms.
Hardness (GPG or PPM)
Measures dissolved calcium and magnesium. This is the primary reason people buy water softeners. Hard water causes white scale on faucets, shower doors, and inside water heaters. It also makes soap less effective, so you use more. Anything above 7 GPG (120 PPM) warrants a softener for most households.
Iron (PPM)
Dissolved iron above 0.3 PPM causes orange-rust stains on sinks, toilets, and laundry. "Clear water iron" (ferrous) is invisible from the tap but stains after exposure to air. "Red water iron" (ferric) is visible immediately. Well water commonly contains both types.
Manganese (PPM)
Similar to iron but causes dark brown or black staining. The EPA secondary standard is 0.05 PPM. At 0.1 PPM and above, a dedicated manganese filter is recommended. Manganese also affects taste and can build up in plumbing over time.
TDS - Total Dissolved Solids (PPM)
Measures everything dissolved in the water: minerals, salts, metals, and organic compounds. Low TDS (under 300 PPM) is typical of good-quality water. High TDS (above 500 PPM) affects taste and may indicate contamination. A reverse osmosis system is the standard fix for high TDS at the drinking faucet.
pH
Measures acidity or alkalinity on a 1-14 scale. The ideal range is 7.0-8.5. Water below 6.5 is corrosive and can leach copper, lead, and other metals from your plumbing. Water above 9.0 tastes bitter and can irritate skin. An acid neutralizer corrects low pH.
Nitrate (PPM)
Nitrate above 10 PPM is a health risk, especially for infants and pregnant women. Common sources include fertilizer runoff, septic systems, and animal waste. Boiling water concentrates nitrate rather than removing it. Reverse osmosis is the most effective residential treatment.
Chlorine (PPM)
Municipal water supplies add chlorine for disinfection. Residual chlorine under 1 PPM is normal and safe. Above 2 PPM, you may notice a strong taste and smell, and it can dry out skin and hair. A whole-house carbon filter removes excess chlorine effectively.
Bacteria & Sulfur
Coliform bacteria is a pass/fail test. Any detection means your water is potentially contaminated and needs treatment before drinking. A rotten egg smell indicates hydrogen sulfide gas, which is produced by sulfur bacteria in well water. Both require specific treatment systems.
When to Test Your Water
Annual Testing (Well Water)
If you rely on a private well, test at minimum once per year for bacteria, nitrate, pH, and TDS. The EPA does not regulate private wells, so testing is your responsibility. Spring is the best time to test since snowmelt and rain can introduce contaminants.
After Major Events
Retest your water after any flooding near the well, plumbing repairs, new construction in the area, or if you notice any change in taste, color, or smell. Earthquakes, heavy storms, and nearby drilling can all affect groundwater quality.
New Home Purchase
Always test water before buying a home with a private well. A comprehensive test covering hardness, iron, manganese, pH, TDS, nitrate, bacteria, and lead costs $100-$250 from a certified lab. Many mortgage lenders require it. City water users can request their utility's annual Consumer Confidence Report for free.
Specific Concerns
Test for lead if your home was built before 1986 (lead solder was common). Test for arsenic if you live in an area with known geological arsenic. Test for radon in water if your area has elevated airborne radon levels. These specialized tests go beyond the standard panel but are important for specific risk factors.
Treatment Options Explained
| System Type | What It Removes | Typical Cost | Best For |
|---|---|---|---|
| Water Softener | Calcium, magnesium (hardness) | $500-$2,500 | Hardness above 7 GPG |
| Iron Filter | Iron, manganese, sulfur | $800-$2,000 | Iron above 1 PPM, well water |
| Reverse Osmosis | TDS, nitrate, lead, arsenic | $200-$600 | High TDS, nitrate, drinking water |
| UV Sterilizer | Bacteria, viruses | $300-$800 | Bacteria present, well water |
| Acid Neutralizer | Low pH (raises to neutral) | $500-$1,500 | pH below 6.5 |
| Carbon Filter | Chlorine, taste, odor | $100-$500 | City water chlorine taste |
When multiple treatments are needed, order matters. Install them in this sequence: acid neutralizer first (protects downstream equipment), then sediment filter, then iron filter, then water softener, then UV sterilizer (clean water is needed for UV to work), and finally an RO system at the kitchen sink.
Ready to Size a Water Softener?
If your hardness results show you need a softener, our sizing calculator tells you the exact grain capacity for your household.
Use Our Sizing Calculator →Frequently Asked Questions
How do I read my water test report?
A water test report lists measured levels for parameters like hardness, iron, pH, TDS, nitrate, chlorine, and bacteria. Each value is compared against EPA or industry thresholds to determine if your water is safe, borderline, or needs treatment. Our interpreter above color-codes each parameter for you automatically.
What is considered hard water?
Water hardness is measured in grains per gallon (GPG) or parts per million (PPM). Water under 3 GPG (51 PPM) is soft. Water between 3-7 GPG is slightly hard. Water between 7-10 GPG is moderately hard. Above 10 GPG is hard, and above 14 GPG is very hard. Most households with hardness above 7 GPG benefit from a water softener.
What do the iron and manganese numbers mean?
Iron above 0.3 PPM causes orange-brown staining on fixtures, laundry, and dishes. Manganese above 0.05 PPM causes dark brown or black staining. Both affect taste. At high levels (iron above 1 PPM, manganese above 0.1 PPM), a dedicated iron filter is recommended before the water softener.
What should I do if my water tests positive for bacteria?
If coliform bacteria is detected, stop drinking the water immediately. Contact your local health department for guidance. A UV sterilizer installed on the main water line kills 99.99% of bacteria and viruses. Retest after treatment to confirm the bacteria is eliminated. Well owners should also inspect the well cap and casing for damage.
How often should I test my well water?
Test your well water at least once per year for bacteria, nitrate, pH, and TDS. Test for hardness and iron every 2-3 years unless conditions change. Always retest after flooding, plumbing work, new well drilling nearby, or if you notice changes in taste, smell, or appearance.
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