Drinking Water Management
Storage and Management of Disinfecting Chemicals
Operations and Maintenance
Safety and Security
Safe Drinking Water Act Compliance
Many tribal governments are responsible for operating public water systems (PWSs). A regulated PWS is any water system that makes water available for drinking to 15 or more connections, or regularly serves an average of 25 individuals daily at least 60 days out of the year. PWSs are designed to provide and maintain reliable, safe, high-quality drinking water to consumers in their homes, at work, at school, at restaurants, roadside rest stops, and any other place the PWS makes water available to the public.
- A Community Water System (CWS) supplies water to the same residential population year-round. Examples include cities, towns, and rural water systems.
- A Non-Transient Non-Community Water System (NTNCWS) regularly supplies water to at least 25 of the same people at least six months per year - but not to their residences. Examples include schools and factories that have their own water supply.
- A Transient Non-Community Water System (TNCWS) provides water to at least 25 different people a day for six months out the year (typically in a place where people do not remain for long periods of time.) Examples include restaurants, rest stops, and campgrounds that have their own water supplies.
The SDWA, giving EPA the authority to protect the public from chemical, physical, radiological, and microbiological contaminants in their drinking water. EPA has used this authority to develop regulations establishing maximum contaminant levels (MCLs) for many substances that can be harmful in drinking water and treatment technique regulations requiring public water systems to remove or inactivate other substances found in their source water. Other SDWA regulations are intended to protect the quality of source water and to ensure treated drinking water remains safe until it is delivered to consumers.
Tribal PWSs are required to comply with all drinking water regulations that apply to their systems. They are also responsible for ensuring that the required water samples are collected and tested, and that the results of those tests and other required reports are sent to EPA, or to the tribal regulatory office if the tribe has been approved to exercise primary enforcement authority ("primacy") for its drinking water program. To date, only the Navajo Nation has been approved for primacy. EPA administers the drinking water program for all other tribes.
The drinking water requirements can be found at 40 CFR 141 . The rules applicable to a particular public water system can vary depending on the PWS's size (number of people it serves) and type (community, non-transient non-community, or transient non-community), and the type of source water (groundwater or surface water) the PWS relies upon. Tribal PWS operators should contact EPA or its circuit riders to make sure they have correctly identified the requirements that their systems must meet.
The operations necessary to provide and maintain reliable drinking water include water treatment and water distribution, and are discussed in detail below.
The amount and type of treatment applied by a PWS varies with the source water type and quality. Drinking water can come from either surface water or groundwater sources. Water pumped from wells drilled into underground aquifers - geological formations containing water - is called groundwater. Many, but not all, groundwater systems can satisfy all federal drinking water requirements without applying any treatment. Water that is pumped and treated from sources open to the atmosphere, such as rivers, lakes, and reservoirs, is known as surface water. Surface water sources, which are more exposed to contaminants in stormwater runoff and to microbiological contaminants, typically require more rigorous treatment. More than 90 percent of tribal PWSs use groundwater sources, but the approximately 75 tribal PWSs that use a surface water source are often the tribal systems serving the largest populations. Improper operation of these large systems could put thousands of people at risk of illness or death.
Because water from both surface water and groundwater sources can become contaminated if it is not protected, a PWS must shelter its water source from chemical spills, human activities that can degrade water quality, and careless sanitary procedures. It is easier and more cost-effective for a PWS to start with relatively clean water. Cleaning up contaminated source water and making it safe to drink can be complicated, costly, and sometimes impossible.
Once the quality of its source water has been determined, a PWS should consult with EPA and its partners to develop an appropriate treatment process, or "treatment train." A typical treatment train for PWSs that use surface water sources will include screening at the point of intake to strain out large objects and fish; presedimentation to allow many suspended solids to settle out of the source water by simple gravity; coagulation/flocculation/sedimentation to cause more of the suspended solids, chemicals, and impurities to settle out of the water; filtration to remove finer suspended particles and larger microbial contaminants; and disinfection to kill or inactivate microscopic organisms that can cause disease.
Tribal PWSs should note that some treatment processes or technologies can produce waste products or waste streams that are themselves regulated. Settling ponds are intended to capture solids and chemicals removed from the source water and chemicals used to trigger coagulation and flocculation. Residual wastes can collect in filter media where they can become trapped or released as backwash during filter cleaning operations. The type of waste generated depends on the treatment technology selected and can also be affected by the quality of the source water. While the treatment trains used by tribal PWSs typically will not generate hazardous wastes, a tribe should work with EPA or its circuit riders to identify potential waste products and streams and to determine if they must be handled in accordance with the requirements of RCRA and the CWA. EPA can also help the tribe determine the best waste disposal option based on the system's treatment train, the type of waste or wastewater generated, and level of contaminants present in the waste streams.
Storage and Management of Disinfecting Chemicals
- Emergency Release Notification (EPCRA Section 304)
- Hazardous Chemical Inventory and Reporting (EPCRA Sections 311 and 312)
- Risk Management Planning (CAA Section 112 (r))
A tribal PWS that disinfects its water is likely to use, and have on site, chlorine, chloramines, or chlorine dioxide. These are the most commonly used disinfection agents because they effectively kill or inactivate biological contaminants in source water and remain in the treated water to prevent recontamination in the distribution system. If the disinfecting PWS is large enough to store or use a specified amount of these chemicals, it will be subject to the applicable planning and reporting requirements of OSHA, EPCRA, FIFRA (if using chlorine or other registered pesticides) and Section 112(r) of the CAA. The PWS should investigate disinfection technologies before deciding which method to use, and contact EPA if it has any questions.
Distribution systems deliver drinking water from the treatment plant to the consumers. A distribution system can include storage facilities or tanks, water mains, service lines (lines from water main to the building or property being served), and the associated valving and accessories. The distribution system must maintain adequate and constant water pressure to prevent contaminants from being drawn into the pipes, and must maintain a disinfectant residual to ensure that microbial contamination does not occur after water leaves the treatment plant.
Distribution systems can be contaminated through cross-connections. A cross-connection is defined as an actual or potential connection between a potable supply of water and a non-potable supply and are typically due to poor plumbing practices. Cross-connections allow the entry of contaminated water from sources such as an adjacent sewer pipe, an industrial source, or stormwater runoff. The contaminant enters the distribution system if the pressure of the polluted source exceeds the water pressure in the distribution system. This action is called backflow and may be due to backpressure or back siphonage. Cross connections lie dormant until backflow occurs. Cross connections controls to prevent distribution system contamination can be found in a variety of regulations, standards, and codes, including plumbing codes, health codes, and building codes. These vary widely throughout Indian country. Tribal PWSs should check with their EPA Regional Office for more information.
Operations and Maintenance
Proper operation and maintenance (O&M) is essential to ensuring that a PWS effectively and efficiently provides safe drinking water to its consumers. Ensuring that the entire water system infrastructure (i.e., storage, treatment facilities, and distribution systems) is properly maintained can prevent entry and growth of microbiological contaminants in the distribution system and preserve the system's overall structural integrity. Proper O&M can also result in lower costs to the PWS. These O&M costs include:
- The cost of labor (including training of operators)
- Energy costs
- The cost of rehabilitating or replacing equipment
- Chemicals costs
- The cost of waste disposal
- Safety and security costs
- Other miscellaneous costs like insurance and taxes
A preventive maintenance program will allow a tribal PWS to maximize the usefulness of equipment and piping, help avoid problems, and cut down or delay rehabilitation or replacement costs. Some key items and equipment that should be included in a preventive maintenance program include:
- Monitoring equipment calibration
- Pump inspection and maintenance
- Inspection and maintenance of disinfection system
- Valve inspection and maintenance
- Maintenance and repair of water mains and storage tanks or reservoirs
- Distribution system flushing
- Cross connection and backflow prevention
- Distribution system piping repair or replacement
- Safety (confined space measures, lockout/tagout procedures, oxygen deficiency hazard measures)
The above list is not all-inclusive and tribal PWSs should tailor their preventive maintenance programs to meet their specific needs. In implementing a preventive maintenance program, a tribal PWS should follow manufacturer equipment instructions and recommendations, plumbing, electrical, and building codes, proper engineering and construction practices, safety standards, MSDSs, and any other applicable requirements (including permits). Tribal PWSs should contact their EPA Regional Office for more information on developing and implementing a preventive maintenance program, including system-specific O&M issues.
Sanitary Surveys help to ensure proper PWS operation. A sanitary survey is intended "to evaluate and document the capabilities of the water system's sources, treatment, storage, distribution network, operation and maintenance, and overall management to continually provide safe drinking water and to identify any deficiencies that may adversely impact a public water system's ability to provide a safe, reliable water supply." Sanitary surveys are indispensable for ensuring the delivery of safe water on a sustainable basis. When conducted properly and with appropriate follow-up, sanitary surveys can:
- Reduce the risk of waterborne disease
- Provide an opportunity to educate system operators
- Identify systems needing technical or capacity development assistance.
Safety and Security
A tribal PWS must comply with safety requirements like any other work environment. For example, the use of hazardous chemicals, such as chlorine for disinfection, at a PWS would require MSDSs. Extreme caution should always be exercised by anyone performing O&M procedures. Safety procedures such as confined space, trench shoring (for excavations), and lock-out/tag-out should always be used. Other regulations may also apply.
Security practices should also be incorporated into the every day business functions of a tribal PWS. Activities such as fence cutting and lock picking, previously dismissed as harmless, may be indications of more serious threats to the PWS. Tribal PWSs must be prepared to respond to threats, as well as a wide range of emergencies, such as natural disasters. Improved security preparations provide for a more effective and efficient response. A tribal PWS should contact EPA for more information on tools, training, and technical assistance pertaining to water system security and emergency response.
Safe Drinking Water Act Compliance
Tribal PWSs are responsible for complying with SDWA requirements with respect to water quality, treatment techniques, recordkeeping, and reporting. As part of those regulations, water supply facilities are required to sample and analyze the water for specific chemicals and microbiological organisms to ensure that applicable treatment techniques are followed and the MCLs are not exceeded. Tribal PWSs are in violation and may be subject to fines and other penalties if any of the following occur:
- The system exceeds an MCL
- The system fails to comply with a treatment technique
- The system fails to monitor for contaminants
- The system fails to report monitoring results to the Primacy Agency
- The system fails to provide the appropriate public notification
All tribal PWSs also must maintain records, including sample analyses, actions taken to correct violations, sanitary surveys of the system, and variances or exemptions granted to the system.
When MCLs are exceeded, tribal PWSs must notify EPA, or their tribal regulatory office if they have been granted primacy. A PWS that exceeds an MCL is also required to notify its consumers of the violation. The public notification requirements are based on the severity of the violation. Generally speaking, if the contaminant at issue can make people sick immediately, the notification must be made within 24 hours. EPA's Final Drinking Water Public Notification Regulations Web site provides more information.
In addition, every CWS is required to provide its customers annual Consumer Confidence Reports that describe the quality of the system's water source, identify any regulated contaminants detected in the drinking water, and note any violations of drinking water standards. For more information, go to EPA's Consumer Confidence Report (CCR) Web site provides additional information.
For more information about any issues related to supplying public drinking water, please contact your Regional EPA Tribal Drinking Water Coordinator listed in Tribal Compliance Assistance Center's Contacts page.
For related information visit EPA’s National Indian Country Enforcement and Compliance Assurance Priority site and EPA’s Enforcement and Compliance Assurance Program in Indian country site.