A key performance indicator (KPI) is a metric used to evaluate factors that are crucial to the success of an organization.  For Drinking Water Systems KPIs tend to be based on costs and regulatory compliance.  Sugguested KPIs:

• Cost per gallon treated
• % unaccounted - Water Produced vs Water Billed for

There are several national programs that offer KPIs and optimization goals:

National Area Wide Optimizaton Program (AWOP) - https://www.epa.gov/dwstandardsregulations/optimization-program-drinking-water-systems

AWOP is a systematic approach developed by the USEPA, Technical Service Center (TSC) in Cincinnati and Process Applications Inc. (PAI) to reduce and eliminate fluctuations in water quality and treatment facility performance through enhanced process control. Particular attention was emphasized on turbidity removal performance focusing on the multiple barrier approach. For a conventional treatment plant the multiple barriers are flocculation and sedimentation, filtration, and the disinfection barrier. The first barrier focuses on maximizing the settling of particles which reduces the workload of the filters. The filtration barrier provides removal of particles that may harbor disease causing organisms. The disinfection barrier provides adequate contact time in the presence of a disinfectant to inactivate microbial contaminants that may have passed through the first and second barriers. What is optimization in relation to AWOP? Optimization refers to an approach for water systems to improve drinking water quality beyond compliance requirements to enhance public health protection. It is achieved through enhanced process control using existing staff and facilities. Optimized performance is measured relative to optimization goals. Optimization, which is a continuing process, can be considered achieved when the following goals are being met at a water treatment facility.

Sedimentation

• Settled water turbidity is less than 1.0 nephelometric turbidity units (NTU) 95 percent of the time when the average raw water turbidity is less than or equal to 10.0 NTU during the same period.

• Settled water turbidity is less than 2.0 NTU 95 percent of the time when the average raw water turbidity is greater than 10 NTU during the same period.

Filtration

• Filtered water turbidity is less than 0.10 NTU 95 percent of the time based on maximum values recorded.
• Maximum turbidity of any filtered water measurement is never greater than 0.3 NTU.
• Filter backwash is initiated before effluent turbidity exceeds 0.1 NTU.
• Filter to waste until is less than 0.1 NTU.
• Maximum filtered water measurement is less than 10 particles (in the >2 micron range) per millimeter (if particle counters are available).

Total Organic Carbon (TOC) Removal Optimization Performance Goal

• TOC leaving the plant and entering the distribution system < 1.7 mg/L

Disinfection By-Product (TTHM and HAA5) Optimization Performance Goals

• Individual Site Goal: the most recent quarterly maximum Locational Running Annual Average (LRAA) TTHM/HAA5 values should not exceed 70/50 ppb (which is more stringent than the Stage 2 DBPR compliance requirements.
• Long-Term System Goal: average of maximum LRAA TTHM/ HAA5 values not to exceed 60/40 ppb (i.e., the average of the last eight quarterly Max LRAA values not to exceed 60/40 ppb).

Disinfectant Residual Optimization Performance Goals

• Maintain 0.2 mg/L residual at all locations in the distribution system, at all times, to provide a disinfection barrier against microbial contamination in a free chlorine system.
• Maintain > 1.50 mg/L monochloramine residual at all locations in the distribution system, at all times, to provide a disinfection barrier against both microbial contamination and nitrification prevention in chloramine systems.
• Maintain a detectable free ammonia residual in the plant effluent < 0.10 mg/L as NH3-N in chloramine systems.

Chlorine and Ammonia Dosing Guideline

• Maintain a chlorine-to-nitrogen mass ratio between 4.5:1 and 5.0:1 (or chlorine-to- ammonia mass ration between 3.7:1 and 4.1:1), which should result in a detectable free ammonia in the plant effluent that is < 0.10 mg/L as NH3-N.

Storage Tank Operational Guideline

• Maintain low average turnover time (< 5 Days) at all times or establish and maintain a tank-specific water turnover rate at each storage facility.
• Maintain good mixing at all times