Four results on your water report all describe the minerals and salts dissolved in your water: hardness, total dissolved solids (TDS), conductivity, and chloride. None of them is a health concern at the levels typically found in well water. They mostly affect scale buildup, taste, and plumbing, and hard water also changes how soap behaves: minerals keep soap from lathering well and leave a film behind. Here’s what each one tells you, and when it’s worth doing something about.
Hardness
Hardness measures dissolved calcium and magnesium, picked up as groundwater moves through rock. These minerals are harmless, and are in fact nutrients we need. The trouble comes when water is heated or evaporates: hard water leaves white scale on fixtures, shortens the life of water heaters, and keeps soap from lathering well.
Your report gives hardness two ways: in milligrams per liter (mg/L) and in grains per gallon (gpg). One grain per gallon equals about 17 mg/L. Here’s how to read it:
Classification | Grains per gallon | mg/L |
|---|---|---|
Soft | Less than 1.0 | Less than 17 |
Slightly hard | 1.0 to 3.5 | 17 to 60 |
Moderately hard | 3.5 to 7.0 | 60 to 120 |
Hard | 7.0 to 10.5 | 120 to 180 |
Very hard | More than 10.5 | More than 180 |
Below about 7 grains per gallon, most households won’t notice much scale or soap film. Above that, a water softener starts to make sense. Whether to soften is a matter of preference, not health.
If you do install a softener, keep a few things in mind:
- It adds sodium. A softener swaps calcium and magnesium for sodium. Anyone on a low-sodium diet may want an unsoftened tap for drinking, or a potassium-based system.
- Not every tap needs it. Toilets and outdoor spigots can be left on unsoftened water.
- It affects your septic system. Each regeneration cycle sends roughly 50 gallons of salty water to the septic system.
- It interacts with other treatment. A softener can remove small amounts of dissolved iron, but an acid neutralizer for low pH will add hardness back. Plan the whole system together.
Total dissolved solids and conductivity
Total dissolved solids (TDS) is the combined amount of everything dissolved in your water: calcium, magnesium, sodium, chloride, sulfate, and more. The guideline is 500 mg/L. Above that, water can taste salty, bitter, or flat, and it leaves more scale and spotting.
If your test was done for an FHA or VA loan, the report shows total solids instead of TDS. Total solids also counts fine particles suspended in the water, not only dissolved minerals, but it’s compared against the same 500 mg/L limit.
Conductivity measures how easily water carries an electric current. Pure water conducts poorly, and dissolved minerals make it conduct better, so conductivity is a quick stand-in for TDS. In fact, labs often calculate TDS from the conductivity reading. There’s no guideline for conductivity itself.
These two numbers are most useful as a baseline. If conductivity jumps between tests, something has changed in your water. A common cause is road salt or a septic system reaching the well.
Very low TDS isn’t a problem to drink, but soft, low-mineral water combined with low pH tends to be more corrosive to plumbing (see our post on pH).
Chloride
Chloride is half of ordinary salt (sodium chloride). The guideline is 250 mg/L. Above that, water tastes salty and becomes more corrosive to pipes and fixtures. At typical levels, chloride isn’t a health concern, though high chloride usually means high sodium too, which matters for anyone on a low-sodium diet.
Some chloride comes naturally from bedrock. Higher levels usually point to a local source:
- Road salt. Shallow wells near roads or driveways, or downhill from them, are the most vulnerable. Levels can rise after snowmelt in spring, so a spring or fall test gives a better picture than a single winter result.
- Septic systems, including the discharge from a water softener.
Chloride is hard to remove. Reverse osmosis at the kitchen tap works for drinking water, but whole-house removal isn’t practical. The better long-term fix is reducing the source: less salt near the wellhead, and making sure the septic system and well are properly separated.
The bottom line
Hardness, TDS, conductivity, and chloride describe the character of your water more than its safety. Hardness tells you whether a softener is worth considering. TDS and conductivity give you a baseline to compare future tests against. Chloride is worth watching if your well is near a road. Keep your report, and compare it to future tests: a sudden change is often more telling than any single number.
Chester County Home Inspections provides water quality testing throughout Chester County and the surrounding counties. We collect samples using EPA protocols and deliver them to a PA-DEP certified laboratory. If you have questions about your results, get in touch.
Sources
- Water Softening, Penn State Extension
- Common Drinking Water Problems and Solutions, Penn State Extension
- Salt Investigations, Connecticut DEEP
Findings Explained, Not Just Flagged.
Chester County Home Inspections, LLC