API RP 13B-1 provides standard procedures for determining the following characteristics of water-based drilling fluids:

a) drilling fluid density (mud weight);
b) viscosity and gel strength;
c) filtration;
d) water, oil and solids contents;
e) sand content;
f) methylene blue capacity;
g) pH;
h) alkalinity and lime content;
i) chloride content;
j) total hardness as calcium.

Annexes A, B, C and E provide additional test methods which may be used for:
k) chemical analysis for calcium, magnesium, calcium sulfate, sulfide, carbonate, potassium;
l) determination of shear strength;
m) determination of resistivity;
n) drill pipe corrosion monitoring.

Annexes D, F, G and H provide procedures that may be used for:
o) removal of air;
p) sampling, inspection and rejection;
q) rig-site sampling;
r) calibration and verification of glassware, thermometers, viscometers, retort kit cup and drilling fluid balances.