Water Quality Standards

There are multiple professional organizations that establish specific standards according to their fields of study. The most common of these organizations are:

Clinical & Laboratory Standards Institute (CLSI); formerly known as the National Committee for Clinical Laboratory Standards (NCCLS)
College of American Pathologists (CAP) (follows CLSI standards)
American Society for Testing & Materials (ASTM)
United States Pharmacopeia (USP)

American Society for Testing and Materials (ASTM)

Standard Specification for Reagent Grade Water

	Type I	Type II	Type III	Type Iv
Electrical Conductivity Max (pX/cm @ 25C)	0.056	1.0	0.25	5.0
Electrical Resistivity Min (MOhms-cm @ 25C)	18	1.0	4.0	0.2
pH @ 25&#176C	-	-	-	5.0-8.0
TOC max (µg/L)	100	50	200	No Limit
Sodium max (µg/L)	1	5	10	50
Silica max. (µg/L)	3	3	500	No Limit
Chloride max (µg/L)	1	5	10	50

When bacterial levels need to be controlled, reagent grade types should be further discussed as follows:

	Type A	Type B	Type C
Total Bacterial Count Max CFU/100ml	1	10	1000
Endotoxin max. IU.ml	0.03	0.025	-

Clinical and Laboratory Standards Institute (CLSI) (CAP)

CLRW Type I Type II Type III

Bacteria Bacteria (CFU/ml) <10 <1 <100 <1000

Pyrogens (Eu/ML) - <0.03 n/a n/a

Ions Resistivity (MΩ-cm @ 25C) >10 >18 >1 >0.05 K50Ω

Colloids Silica (ppb) - <10 <100 <1000

Particles Particles >0.2 µm (units/mL) Include 0.22 µ filtration <1 (0.22 µ filtration required) n/a n/a

Organics Total Organic Carbon ppb <500 <10 <50 <200

United States Pharmacopoeia Standards (USP)

Purified Water WFI Water

Electrical Conductivity Max (µS/cm @ 25C) <1.3 <1.3

Total Organic Carbon (TOC) (ppm) <0.5* <0.5*

Endotoxin (EU/ml) n/a <0.25

Bacteria (guideline only) <100 cfu/ml <10 cfu/100ml

* Or pass oxidisable substance test

When bacterial levels need to be controlled, reagent grade types should be further discussed as follows:

Type A Type B Type C

Total Bacterial Count Max CFU/100ml 1 10 1000

Endotoxin max IU.ml 0.03 0.25 -