U.S. citizens generally expect to be able to drink their tap water with minimal health risk. While the quality of U.S. drinking water is superior to that in many parts of the world, not all U.S. citizens are receiving the same quality of water service. For example, during one recent 27-month period, 23.5 percent of U.S. community water systems violated safe drinking water standards one or more times for microbes that indicate the possible presence of bacteria, viruses, or parasites associated with human illnesses. Nearly 600 waterborne disease outbreaks have been reported in the past two decades.
Meeting drinking water standards is most difficult for water systems in small communities. Small communities often cannot afford the equipment and qualified operators necessary to ensure compliance with safe drinking water standards. Increases in both the number of drinking water regulations and the number of small community water systems over the past three decades have compounded the problem of providing safe drinking water to small communities. For example, the number of water systems serving 500 or fewer people increased seven-fold, from 5,000 to more than 35,000, between 1963 and 1993; the number of systems serving 501 to 10,000 people increased by more than 60 percent. Over this same time period, the number of contaminants regulated by federal drinking water standards increased from fewer than 20 to more than 100.
This report focuses on how to provide safe drinking water to small communities. It discusses technologies for small water systems, how to streamline pilot testing of these technologies to make them more affordable, financing and management of small systems to ensure their sustainability, and training of small
system operators. The report was written by the National Research Council's Committee on Small Water Supply Systems. The committee was appointed in 1994 at the request of the U.S. Environmental Protection Agency (EPA) to study the problem of providing water service to small communities. Its membership consisted of 12 experts in water treatment, utility management, finance, and public health.
As discussed in this report, the solution to the problem of providing safe drinking water to small communities has three elements, each equally important: (1) providing affordable water treatment technologies, (2) creating the institutional structure necessary to ensure the financial stability of water systems, and (3) improving programs to train small system operators in all aspects of water system maintenance and management.
Status of Small Systems
More than 54,000 small water systems (defined for this report as those serving 10,000 or fewer people) provide drinking water to approximately 20 percent of the U.S. population. Sixty-six percent of these systems serve communities with populations of 500 or fewer.
While some small communities are in wealthy areas, most small communities have difficulty raising the capital needed to upgrade their water systems and the revenue needed for day-to-day water system operation and maintenance. In extreme cases, these small communities can lack water service altogether. For example, as of 1990, more than 1.1 million U.S. households lacked plumbing.
Capital and adequate operating revenue are most difficult to obtain for small communities in nonmetropolitan areas. Average incomes in the smallest of these communities are one-third lower than incomes in larger, metropolitan areas. Unemployment rates can be more than 50 percent higher than those in metropolitan areas. Lenders are often unwilling to provide loans to rural communities because of the small profits generated by these loans. Whether a small system is located in a rural area or a metropolitan one, it will lack the economies of scale of larger communities in providing water service; per-person costs for water service must be higher in small communities than in larger ones to provide the same level of service because the costs are spread over a smaller population.
Small communities that lack adequate revenue for water treatment and distribution can have difficulty complying with the Safe Drinking Water Act. For example, systems serving fewer than 500 people violate drinking water standards for microbes and chemicals more than twice as often as those serving larger communities. Such violations leave these communities vulnerable to outbreaks of waterborne illness. In addition, the large number of violations in small communities poses a serious management problem for the state regulatory agencies responsible for implementing the Safe Drinking Water Act.
Evaluating Technologies for Small Systems
Before looking to technological answers to water quality problems, small water supply systems should exhaust other available alternatives for improving water quality. One option is to find a higher-quality source water, such as by switching from surface water to ground water or relocating a well to a cleaner aquifer. In general, ground water sources are a better choice for small water systems than surface water sources because they are less turbid and have lower concentrations of microbiological contaminants than surface water. A second, nontechnical option for improving small system water quality is to purchase treated water from a nearby utility. Such options are often more cost-effective than attempting to remove contaminants from a poor-quality source water.
When other options are not available and small systems must turn to water treatment processes in order to provide water that meets the requirements of the Safe Drinking Water Act, they may have difficulty raising revenue for capital improvements. One option available for reducing the costs of water treatment for these communities is the use of preengineered ''package plants." Package plants are off-the-shelf units that group elements of the treatment process, such as chemical feeders, mixers, flocculators, sedimentation basins, and filters, in a compact assembly. Package plants do not eliminate the need for an engineer to design the specifics of the on-site application of water treatment equipment. Nevertheless, because package systems use standard designs and factory-built treatment units that are sized, assembled, and delivered to the customer instead of being custom built on-site, such systems have the potential to significantly reduce the engineering and construction costs associated with a new water treatment system.
Site-specific pilot testing requirements can significantly increase the costs of package water treatment plants, partially offsetting the cost savings these systems offer. State regulators often require pilot tests of all new treatment systems other than chlorinators. Often package plants must be evaluated over and over again for source waters having similar quality but located in different communities. Pilot tests can last anywhere from several weeks to 1 year or more. Extensive pilot testing reduces the savings achieved by having the package plants designed and assembled at a central facility. Manufacturers have reported that pilot testing can increase the costs of their equipment by more than 30 percent. For example, according to one manufacturer, a 6-month pilot test can add $16,000 to the cost of a $45,000 package filtration system.
Certification of package plant performance by an independent third party would reduce package plant costs by reducing, although not eliminating, the need for site-specific testing. Currently, no national program exists for certifying drinking water treatment systems other than point-of-use (POU) and point-of-entry (POE) devices used in individual homes. The National Sanitation Foundation (NSF) International, which certifies in-home water treatment equipment, is
currently cooperating with the EPA to develop a verification program for package plants. This program, launched in late 1995, is in its beginning phases and is currently funded for a 3-year period. Support for the program should continue, because it could reduce the costs of drinking water treatment technologies for small communities. Once the program is established, testing fees provided by equipment manufacturers will sustain most of its costs.
A key component of a national pilot testing and verification program for package plants is standard protocols for equipment testing. Currently, such protocols do not exist. Water treatment system designers generally conduct bench and pilot studies using their own individual methods and parameters for documenting water quality. As a consequence, it is difficult to compare data sets developed by different investigators. Establishment of standard protocols that measure the parameters covered in Safe Drinking Water Act regulations would allow data collected in one location to be applied elsewhere.
Another key component of a package plant testing and certification program is a national database for reporting test results. Currently, no such database exists. Considerable "reinvention of the wheel" occurs as new tests are required to verify technologies at each new location even if identical tests were performed elsewhere on water of a similar quality. Such a database could be created by expanding the Registry of Equipment Suppliers of Treatment Technologies for Small Systems (RESULTS) database at the National Drinking Water Clearinghouse in West Virginia. The expanded database should cover all of the available technologies, use standard formats for reporting data, and include complete information about raw water quality, finished water quality, and operation and maintenance costs for each technology.
While development of standard protocols for testing drinking water treatment technologies is a desirable goal, it is essential to recognize that the degree to which pilot testing can be centralized in order to reduce site-specific testing varies considerably depending on the type of technology, the nature of the water to be treated, and the availability of data documenting the performance of the technology on waters of various qualities. For many technologies, some aspects of process performance can be tested in a central facility, while others need to be evaluated for each source water treated. Following are some general principles that apply to pilot testing of various classes of water treatment processes (see Chapter 4 for details):
- Site-specific pilot testing of aeration systems is not necessary; performance can be predicted with design equations.
- For membrane systems, much of the detailed evaluation can be based on pilot tests or full-scale applications elsewhere. However, systems using ground water will need to evaluate the potential for chemical scaling of the membranes. Surface water systems will need to test the potential for the source water to foul
- the membranes and determine whether pretreatment is required to removed particulate matter ahead of the membranes.
- For granular activated carbon adsorption systems, some degree of source water-specific testing is necessary because the ability of the carbon to adsorb a target contaminant varies significantly with the chemical composition of the raw water. In cases where the raw water has a low concentration of organic matter, such as in ground water, inexpensive bench-scale columns can adequately predict performance; for surface water systems, pilot tests will be necessary.
- Powdered activated carbon adsorption systems need to be evaluated in bench-scale tests, at a minimum, to determine the effectiveness of the powdered activated carbon on the particular raw water and with the mixing characteristics present in the system.
- Ion exchange and activated alumina systems require some degree of source water-specific bench- or pilot-scale evaluation to determine the potential for competitive adsorption of ions other than the target contaminants, which can affect the life of materials used in treatment.
- Because of the complexity of the chemical processes involved, coagulation/filtration systems require site-specific testing unless an identical coagulation/filtration system is already being used successfully on the same source water. The degree of testing required depends in part on the design of the system and in part on the characteristics of the raw water. In some cases, bench-scale tests using jars to determine appropriate coagulant doses will be adequate.
- diatomaceous earth filtration systems require a few weeks of pilot testing to establish the effectiveness of different grades of diatomaceous earth and to estimate the length of filter runs that might be expected with a full-scale plant.
- For slow sand filtration systems, site-specific pilot testing is necessary, unless a slow sand filter is already treating the same source water at another location, because understanding of these systems is insufficient to allow engineers to predict what filtered water turbidity an operating slow sand filter will attain. Piloting of these systems need not be expensive. Pilot test units can be constructed from manhole segments and other prefabricated cylindrical products.
- Bag filters and cartridge filters need not be pilot tested at each site. Performance of these filters depends on careful manufacture of the equipment and its use on waters of appropriate quality rather than on manipulation of the water or equipment during treatment.
- Lime softening systems need not be pilot tested for small systems using ground water sources; jar testing to determine appropriate process pH and chemical doses is sufficient. Lime softening systems do need to be pilot tested if used on surface water sources with variable quality.
- Disinfection systems using free chlorine, chloramine, chlorine dioxide, or ozone need not be tested at each individual site. The effectiveness of these systems is predicted based on laboratory test results, which regulators consider to be applicable to all systems.
- Current regulations allow small systems to base corrosion control strategies on desk-top reviews of water quality, rather than on pilot tests.
For the smallest of water systems, in particular those serving a few dozen homes or less, POE or POU water treatment systems may provide a low-cost alternative to centralized water treatment. In POE systems, rather than treating all water at a central facility, treatment units are installed at the entry point to individual households or buildings. POU systems treat only the water at an individual tap. If a source water has acceptable quality for drinking except for exceeding the nitrate or fluoride standards, for example, using a POU system to treat the small number of liters per day needed for drinking and cooking might be less costly than installing a central treatment system that could remove the nitrate or fluoride from all water used by the community. Similarly, POE systems can save the cost of installing expensive new equipment in a central water treatment facility. POU and POE systems can also save the considerable costs of installing and maintaining water distribution mains when they are used in communities where homeowners have individual wells.
Regulators often have significant objections to using POE and POU devices. Concerns include the potential health risk posed by not treating all the water in the household (a problem for POU systems), the difficulty and cost of overseeing system operation and maintenance when treatment is not centralized, and liability associated with entering customers' homes. These objections have merit, particularly as system size increases and the complexity of monitoring and servicing the devices increases. Using centralized water treatment should be the preferred option for very small systems, and POE or POU treatment should be considered only if centralized treatment is not possible.
Recommendations: Technologies for Small Systems
- Application of technology (other than disinfection) to improve water quality should be considered only after other options, such as finding a cleaner source of water or purchasing water from a nearby utility, have been exhausted.
- The EPA should continue support for the fledgling water treatment technology verification program that it recently initiated with the National Sanitation Foundation.
- The EPA should oversee development of standard protocols and reporting formats for pilot testing water treatment technologies, especially package plants.
- The EPA should establish a standard national database for water treatment technology information by expanding the RESULTS database at the National Drinking Water Clearinghouse. The database should include complete information on source and finished water quality, in standard units, and costs for each technology. It should be made available electronically, via the Internet.
- State agencies responsible for regulating water systems should assign a
- staff member to continually evaluate the status of knowledge relating to the performance of various water treatment processes of potential use in their jurisdictions. As more performance information is generated on waters of similar quality, the extent of preinstallation testing can be reduced, thus reducing the costs to the small system.
Ensuring Small Water System Sustainability
Affordable technologies can help small communities provide better quality water, but technologies alone will not solve the problems of small water supply systems. Without adequate management and revenues, small communities will be unable to maintain even low-cost technologies. Many small communities lack a fee structure that is adequate to generate the necessary operating revenues, let alone funds for capital improvements. In other communities, the population is too small and average incomes are too low to provide sufficient revenue no matter what the fee structure. Lack of revenue leads to a vicious circle: without funding, water systems cannot afford to hire good managers, but without good managers, water systems will have trouble developing a plan to increase revenues. Institutional changes are needed to decrease the number of unsustainable water systems—that is, the number of systems lacking the resources needed to meet performance requirements over the long-term.
Like businesses, small water systems are experiencing greater external pressure to change in response to the increasing number of regulations and increasing customer expectations. Unlike businesses, however, small systems have generally not done effective business planning. States should encourage small systems to do such planning by developing formal public health performance appraisal programs. Such programs should require each regulated water system in the state to assess its short- and long-term ability to provide adequate quantities of water that meets Safe Drinking Water Act standards. States should provide operating permits only to water utilities that have satisfactorily completed a performance appraisal. Where performance appraisals reveal problems, the states should assist the small water system in resolving the problems.
Performance appraisals should include analyses of the following types of information:
- existence of health orders (for example, boil water orders) issued to the water system or waterborne disease outbreaks in the community;
- the system's record of response to these orders and outbreaks;
- violations of water quality standards, including monitoring requirements;
- the water system's methods for keeping track of its compliance with Safe Drinking Water Act standards;
- the number of staff and their levels of training;
- responses to sanitary surveys (on-site visits by state regulators to inspect system source water, facilities, and operations); and
- whether the water system has an adequate plan specifying how it will meet present and future demands at an affordable cost while complying with the Safe Drinking Water Act and other regulations.
While regulators have long considered waterborne disease outbreaks, compliance with drinking water standards, operator certification, and sanitary surveys when evaluating small water systems, the importance of a comprehensive, forward-looking plan has often been overlooked. Proper planning and financing are key elements in ensuring the sustainability of water systems. Developing a water system plan will cause the utility to examine itself closely and develop a road map for the future. The plan should include information on future trends in service area, population, land use policies, and water demands on both a short-term (next 5 years) and long-term (next 20 years) basis. Based on this demographic information, it should evaluate needed system improvements, the current budget, the expected future budget, and projected future rates necessary to sustain the budget. The level of detail in such plans will vary with the size of the system, with very small systems requiring less detailed plans than larger systems.
If the performance appraisal uncovers problems that compromise the system's sustainability, then the water system either must improve service on its own or restructure by delegating some or all of its responsibilities to another entity, such as a rural electric utility, regional water authority, local government, or investor-owned utility. Restructuring arrangements generally fit one of four categories:
- direct ownership, in which a small system reaches an agreement with another authority to take over system ownership or joins with other nearby systems to form a regional agency;
- receivership or regulatory takeover, in which the state takes responsibility for transferring management of a failing water system to another authority in cases where the system owner does not voluntarily relinquish control;
- contract service, in which a contractor provides specific services, such as operation and maintenance, water quality monitoring, emergency assistance, and billing, on a routine basis; and
- support assistance, in which another utility provides support such as training the small system operator to repair a chlorinator, helping the small system develop a financial management plan, sharing water storage facilities, or making joint purchases of supplies or water to get volume discounts.
Each of these options consolidates some portion of the management and operation of several water systems within a larger agency, reducing costs to the consumer. For example, restructuring may mean that the community no longer
needs to pay for a qualified full-time water systems operator if, through restructuring, several systems can share an operator.
While restructuring can reduce the costs of providing water service to small communities, several barriers can stand in the way of restructuring. Organizations may be unwilling to take over deteriorated systems if they fear being responsible for financing all the necessary system improvements. Similarly, they may fear being held liable if the troubled system is in violation of the Safe Drinking Water Act. In other cases, small system owners may be unwilling to relinquish control to another authority. Incentives need to be provided to encourage qualified organizations to take over management of unsustainable small water systems and to encourage small systems to enter into such arrangements.
Recommendations: Small Water System Sustainability
- States should establish programs requiring all water system to conduct public health performance appraisals. Only systems that have successfully completed a performance appraisal should be issued an operating permit.
- The federal government should limit state revolving fund (SRF) monies for drinking water systems to states with official performance appraisal programs. This will ensure that federal funds are not used to prop up unsustainable systems.
- SRF monies should be made available to public- and investor-owned utilities for assisting in the restructuring of small water systems.
- Federal, state, and local governments should provide tax incentives to organizations that assume responsibility for failing small water systems (see Chapter 5 for details).
- State public utility commissions should allow adjustments to the rate base of larger utilities that assume responsibility for insolvent water systems so that the rate base and depreciation practices can reflect the costs of acquiring the failing system.
- The EPA should provide temporary waivers to utilities for liabilities associated with Safe Drinking Water Act violations in cases where the utility has acquired a failing water company. These waivers should be tied to reasonable compliance schedules.
Training Operators for Small Systems
Even a well-financed water system with the most advanced treatment technologies cannot deliver its water reliably unless its operators are trained adequately. While all 50 states have regulations for certifying water system operators, the programs for training these operators are disjointed and often fail to meet the needs of small system operators.
Training of small system operators is provided through a mix of a state-run
workshops, informal instruction from equipment vendors and state regulators, courses at technical schools or universities, American Water Works Association courses, and rural water associations. These programs are not coordinated in any way. In addition, most operator training programs (and state certification requirements) cover the general theories underlying operation of numerous types of water treatment processes, some of them quite advanced, while operators of smaller systems need specific, hands-on training in only the treatment technologies their systems use. Training and certification programs are particularly deficient in teaching operators about water system management and administration—two areas that are as essential to small water system operation as are treatment and distribution.
The Safe Drinking Water Act Amendments of 1986 authorized the EPA to spend up to $15 million per year to provide technical assistance to small communities struggling to comply with the act's requirements. While the EPA provides $6.5 million annually to the National Rural Water Association and the Rural Community Assistance Program for technical assistance to small water systems, this spending has not resulted in the types of coordinated training programs needed to ensure that all water system operators are adequately trained. More leadership is needed at the national level to improve training programs for small water system operators.
Recommendations: Operator Training
- Funds should be provided to the EPA to establish an organizational work unit, based at EPA headquarters, responsible for identifying the knowledge and skills necessary to operate all aspects of drinking water systems.
- The new EPA work unit should arrange for an independent organization, such as the National Training Coalition or the National Environmental Training Center for Small Communities, to develop multimedia tools to deliver the needed training to system owners and operators across the country.
- The operator training programs should cover all of the areas necessary for running a small water system, including metering, customer service, financing, administration, and human resources management, as well as water treatment, water distribution, and public health.
- The states or their agents, with EPA support and coordination, should deliver the training programs to operators.
- States should rewrite their operator certification laws for small systems to allow small system operators to be certified only for the treatment processes employed in their systems. At the same time, states should institute a requirement that operators have knowledge of all of the skill areas (metering, finance, and so on) necessary for small system management.
In summary, water service to many of the nation's small communities is
currently inadequate. Improving the quality of water service to these communities will require a combination of approaches: finding high-quality water sources, streamlining pilot testing requirements to make technologies more affordable, creating incentives to consolidate the management and financial administration of small systems, and improving programs to train small water system operators. Any one of these approaches alone will be insufficient to solve the problems of small water systems. A water system lacking adequate revenues and a well-trained operator will be unable to afford or maintain equipment, no matter how inexpensive, for water supply, treatment, and distribution. Conversely, a water system with a well-trained operator and sound financial plan may be unable to meet drinking water standards unless it can obtain treatment systems that are within its budget. National and state leadership are needed to improve the delivery of quality water to small communities.