Abstract Power plants with rotating equipment, condition monitoring, and vibration analysis are important. For turbines, other turbovisory instruments are also important. Gas analyzers are important for pollution control and combustion optimization. Both the boiler and turbine performance depends on the feed water and steam quality, especially for supercritical plants. Water quality is maintained by monitoring the same and by various treatments and blowdown. SWAS has been discussed at length covering various sampling methods. Under special instruments, all these condition-monitoring instruments, gas and liquid analytical instruments working principles, standard data sheets have been covered. For special instruments, accessories play an important role, so the same has also been covered. This also includes the selection procedure as well as application and installation notes for various special instruments. Detailed discussions have been presented on treatment requirements for high-pressure, high-temperature supercritical, ultrasupercritical, and A-USC boilers. Also, discussions have been presented on pollution control, including effluent treatment TSS, TDS, and other special instruments such as ammonia, chloride, and mercury analyzers. Discussions have also been included for water chemistry parameters, as recommended by EPRI.