Question 1

What is TDS and what does it measure?

Accepted Answer

TDS stands for Total Dissolved Solids — the total concentration of dissolved substances in water, measured in milligrams per liter (mg/L) or parts per million (ppm). In Central Ohio, TDS is primarily made up of calcium and magnesium (hardness minerals), sodium, bicarbonates, and chlorides. A TDS meter measures electrical conductivity as a proxy for dissolved solids — it doesn't identify specific contaminants.

Question 2

What is a typical TDS reading for Columbus Ohio water?

Accepted Answer

Columbus city water (Columbus Division of Water) typically reads 200–350 mg/L TDS. Delaware County communities (Powell, Lewis Center) often read 300–450 mg/L due to higher hardness. Fairfield County (Pickerington) can reach 400–550 mg/L. Private wells in Central Ohio vary widely — 200–800+ mg/L depending on depth and local geology.

Question 3

Does a high TDS reading mean my water is unsafe?

Accepted Answer

Not necessarily. High TDS in Central Ohio is almost always due to hardness minerals (calcium and magnesium) — which are not health hazards. The EPA secondary standard for TDS is 500 mg/L, based on taste rather than health. However, high TDS does indicate significant scale-causing minerals that damage appliances. A professional water test identifies exactly what's in your water.

Question 4

Does a water softener reduce TDS?

Accepted Answer

A water softener reduces TDS by removing calcium and magnesium (the primary contributors in Central Ohio) and replacing them with sodium. This typically reduces TDS by 100–200 mg/L. However, softened water has slightly elevated sodium — which is why many families add an RO drinking water system to remove the sodium from kitchen tap water.

Question 5

Does reverse osmosis reduce TDS?

Accepted Answer

Yes — reverse osmosis is the most effective method for reducing TDS. A quality RO system removes 90–99% of dissolved solids, producing water in the 10–50 mg/L range. Our alkaline RO systems then add a remineralization stage to bring TDS back to the optimal 50–150 mg/L range for taste and health.

Question 6

Can I trust a cheap TDS meter from Amazon?

Accepted Answer

TDS meters are reasonably accurate for measuring total dissolved solids, but they don't tell you what those solids are. A reading of 400 mg/L could be mostly harmless hardness minerals, or it could include elevated nitrates, PFAS, or other contaminants. A professional water test identifies specific contaminants — a TDS meter only gives you the total.

Question 7

What TDS should my RO water be?

Accepted Answer

A properly functioning RO system should produce water in the 10–50 mg/L range. Our alkaline RO systems add a remineralization stage that brings TDS back to 50–150 mg/L — the WHO-recommended range for optimal taste and mineral content. If your RO output is above 100 mg/L, the membrane may need replacement.

Community	Water Source	Typical TDS	Rating
Columbus (city)	Scioto River / reservoirs	200–320	Good
Westerville	Hoover Reservoir	250–350	Good–Fair
Dublin	Scioto River system	280–380	Good–Fair
Hilliard / Grove City	Scioto / Big Darby	240–340	Good
Powell	Delaware County District	320–420	Fair
Lewis Center	Delaware County District	340–460	Fair
New Albany	City + moraine wells	310–430	Fair
Pickerington	Hocking basin groundwater	360–520	Fair–Poor
Private wells (rural)	Varies by depth/geology	200–800+	Varies

TDS Meter Guide

What Does My TDS Reading Mean?

TDS Frequently Asked Questions

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