Turbidity converter
Convert turbidity between NTU, the older JTU, suspended solids and how deep a Secchi disc stays visible.
That's about the same as the drinking water limit. That is visibly cloudy.
What it means
How cloudy is it?
Suspended solids and Secchi depth are correlations, not conversions: the same NTU from fine clay and from algae gives quite different figures.
Every unit
Your turbidity in every unit
Learn
Three things worth knowing
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Drinking water is below 1 NTU
At 5 NTU water starts to look visibly cloudy. At 1,000 you cannot see your hand a few centimeters down.
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From candles to detectors
The old Jackson turbidity unit was measured by pouring water into a tube until a candle flame beneath it disappeared. One JTU is about 19 NTU.
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Turbidity is not contamination
Clear water can be deadly and cloudy water harmless. Turbidity matters because particles shelter microbes from disinfection, not because cloudiness is itself dangerous.
Shortcuts
Popular turbidity conversions
Background
About turbidity
Turbidity measures how much light water scatters sideways. NTU — nephelometric turbidity units — comes from a detector at 90° to the beam, which is what makes it sensitive to very small particles.
Drinking water is required to stay below 1 NTU, and good treatment plants run at 0.1.