Total Dissolved Solids in Northwest Arkansas Water
Total dissolved solids is the combined weight of everything dissolved in your water: calcium, magnesium, sodium, bicarbonate, chloride, sulfate and much else. A TDS meter measures electrical conductivity and converts it to an approximate number in parts per million.
We are going to be blunt about this one, because TDS is the single most misused number in the water-treatment industry.
Common symptoms
People describe this problem to us in these ways. You may recognise several, or only one.
- A salesperson showing you a high number on a handheld meter
- Water that tastes flat, salty, or heavy
- Spotting and film on glassware
- Scale accumulating faster than expected
- Curiosity after buying a meter online
Potential causes
Naturally dissolved minerals
Water moving through limestone, which is what Ozark groundwater does, dissolves calcium and magnesium. Those minerals raise TDS and are not harmful. In fact they are the same minerals sold as supplements.
Sodium from ion exchange
A water softener exchanges calcium and magnesium for sodium. It does not lower TDS — often it raises it slightly. A meter reading after a softener does not indicate the softener has failed.
Road salt, agricultural runoff or septic influence
Can raise TDS, and in these cases the specific constituents do matter. The TDS number still will not tell you which one.
Naturally low-mineral surface water
Treated surface water often has lower TDS than groundwater. That is a property of the source, not a measure of quality.
This one requires testing to confirm
Here is the part that matters. A TDS meter cannot tell you whether water is safe. It cannot distinguish harmless calcium from arsenic. It does not detect bacteria at all, because bacteria are not dissolved solids. It does not detect most pesticides, PFAS, or organic chemicals, because those are poorly conductive.
Water with a TDS of 300 can be excellent. Water with a TDS of 30 can be contaminated with something dangerous. The number tells you about mineral content and nothing more.
We mention this because the demonstration where a meter reads high and an electrolysis device turns a glass of water brown is a sales theatre trick, not a water test. The brown colour comes from the iron electrode corroding. If someone performs that demonstration in your kitchen, that is a reason to end the conversation.
Treatment technologies commonly used
Which of these is right depends on what your water actually measures. These are the technologies genuinely used for this problem, not a list of everything we sell.
Reverse Osmosis Systems
The technology that genuinely does reduce TDS substantially, and the right choice when the specific dissolved constituents in your water justify it.
Water Testing
A laboratory panel identifies which constituents make up your TDS, which is the only version of this question worth answering.
Drinking-Water Filtration
Where taste is the actual concern.
Questions we are asked about this
What is a good TDS level for drinking water?
The EPA sets a secondary, non-enforceable guideline of 500 ppm for TDS, and it is a guideline about taste and aesthetics rather than health. Many excellent water supplies sit above it and many poor ones sit below it.
My TDS meter reads higher after my water softener. Is it broken?
No. Ion exchange swaps calcium and magnesium ions for sodium ions. The hardness is gone; the dissolved solids are still dissolved. A softener is not supposed to lower TDS and a meter is the wrong instrument for checking it. Test hardness instead.
Should I want zero TDS water?
Not necessarily. Reverse osmosis produces very low TDS water, which many people prefer for taste, coffee and ice. But low TDS is a consequence of the treatment, not a goal in itself, and water with dissolved minerals is not unhealthy.
Someone tested my water and it turned brown. What was that?
An electrolysis demonstration. Passing current through water with iron electrodes corrodes the electrodes and discolours the water. It happens with bottled water and with laboratory-grade water too. It measures nothing.
We work across Northwest Arkansas
City water and private wells, in Benton, Washington, Madison and Carroll counties.