Turbidity!!

Examples of NTU
Waste Water 70-2000 NTU
Final outlet sewage treatment plant 4-20 NTU
Well Water 0.05 – 10 NTU
Potable water 0.05 – 1.5 NTU
Milk > 4000 NTU
Orange juice 300 – 900 NTU
Thats high quality H2O!