This recommended practice 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; k) low-gravity solids and weighting material concentrations. Annexes A through K provide additional test methods that may be used for: ?? chemical analysis for calcium@ magnesium@ calcium sulfate@ sulfide@ carbonate@ and potassium; ?? determination of shear strength; ?? determination of resistivity; ?? removal of air; ?? drill-pipe corrosion monitoring; ?? sampling@ inspection@ and rejection; ?? rig-site sampling; ?? calibration and verification of glassware@ thermometers@ timers@ viscometers@ retort cup@ and drilling fluid balances; ?? permeability plugging testing at high temperature and high pressure for two types of equipment; ?? Sag testing.