Using Sanitary Survey Findings to Identify Risk Management Challenges

Sanitary surveys are conducted at all public water systems (PWSs) in the United States to assess their capability to supply safe drinking water. These surveys are used to identify risks or deficiencies within water system infrastructure, operations, and management and are an important tool for primacy agencies to oversee and assist PWSs in complying with the Safe Drinking Water Act (SDWA). States or other agencies with primacy—i.e., the authority to implement and enforce US Environmental Protection Agency (EPA) regulations—are responsible for completing sanitary surveys and reporting information collected to EPA.

In this study, we reviewed information collected by primacy agencies during sanitary surveys to identify the most frequent deficiencies found at PWSs in the United States. Analysis of deficiencies found during sanitary surveys helps to characterize the potential challenges faced by water systems in providing safe drinking water and helps systems and regulatory authorities prioritize risk management efforts and provide technical assistance.

Deficiencies were identified using sanitary survey data reported to EPA’s Safe Drinking Water Information System (SDWIS, federal version; EPA 2017a). Within SDWIS, records were extracted from 48 states and the District of Columbia for sanitary surveys conducted at surface water systems, including systems with ground water under direct influence of surface water (GWUDI) from Jan. 1, 2010, to Dec. 31, 2017. Our analyses indicate that the most prevalent sanitary survey deficiencies reported to SDWIS were found in the areas of monitoring and reporting, finished water storage, and treatment. These results will help primacy agencies and PWSs to better evaluate water system infrastructure and utility training needs.

Sanitary Survey Components and Requirements

In the United States, sanitary surveys are required under the 1998 Interim Enhanced Surface Water Treatment Rule (IESWTR) (EPA 1998) and the 2006 Ground Water Rule (GWR) (EPA 2006a) for surface water systems (including GWUDI systems) and ground water systems, respectively. They must be conducted at least once every three years for community and once every five years for non-community PWSs (40 CFR § 142.16, Special Primacy Requirements), but requirements for community water systems can be reduced to every five years if they meet specified performance criteria.

Sanitary surveys are used in conjunction with other regulatory and nonregulatory approaches to accomplish the following:

• Identify potential issues that may result in public health risks

• Enhance communication between the water system and regulator

• Help PWSs maintain regulatory compliance

Under the IESWTR and GWR, complete sanitary surveys comprise eight water system areas, which are referred to as “elements”:

• Source

• Treatment

• Distribution System

• Finished Water Storage

• Pumps

• Monitoring and Reporting

• Operator Compliance

• Management and Operation

Primacy agencies have flexibility in developing and implementing their sanitary survey programs, and differences between programs can include the following:

• Required training and personnel for conducting the surveys (e.g., primacy agency or primacy agency–appointed)

• The content and format of inspection forms and reports, deficiency definitions

• Priority areas within the eight elements

Further, primacy agencies may choose to conduct sanitary surveys more frequently than the minimum requirements. They may also conduct sanitary surveys using a phased approach, evaluating specific elements over multiple on-site visits (40 CFR § 142.16 (3)(iii)). In recent years, some components of the sanitary survey have been done virtually.

Significant and Minor Deficiencies

Deficiencies identified under the eight water system elements are commonly reported as either significant or minor. Significant deficiencies are defined as “serious sanitary deficiencies identified in water systems which include, but are not limited to, defects in design, operation, maintenance, or a failure or malfunction of the sources, treatment, storage, or distribution system that the primacy agency determines to be causing, or has potential to cause, the introduction of contamination into the water delivered to consumers” (EPA 2019). Examples of significant deficiencies include cross connections, cracks in the walls of storage tanks, and on-going, unaddressed violations (EPA 2019). Examples of minor deficiencies include failure to update water distribution maps or upgrade treatment equipment (EPA 2008). Minor deficiencies may be used to characterize issues that do not directly affect public health, although there may be longer-term public health implications in some cases if they are not corrected.

The primacy agency determines deficiencies and corresponding corrective actions. Under the GWR, primacy agencies are required to define at least one significant deficiency for each of the eight elements of a sanitary survey. For systems using surface water or GWUDI (referred to as “subpart H” systems, per CFR § 141.70, Subpart H—Filtration and Disinfection), the primacy agency must describe how it will decide whether a deficiency identified during a sanitary survey is significant (40 CFR § 142.16(b)(1)(ii)). As such, similar or identical deficiencies could be designated as either significant or minor depending on primacy agency implementation and other factors. For example, one state’s online procedures for conducting sanitary surveys noted that some deficiencies could be either significant or minor, depending on the circumstances. Additionally, surveyors can make recommendations on improvements to water system components and operations that are not directly associated with deficiencies.

Additional Benefits of Sanitary Surveys

Sanitary surveys have benefits beyond finding and fixing deficiencies. For example, sanitary surveys have been recognized as tools for building capacity development (Shanaghan et al. 1998), which improves a system’s ability to deliver high-quality water by ensuring it has adequate technical, managerial, and financial capacity. Rayburn et al. (2011) referred to sanitary survey relevance for addressing distribution system issues as part of a broader effort to identify priorities for distribution system research and information collection. Blanchard and Eberle (2013) described the use of sanitary surveys in Washington State as a tool for reducing emergency requests.

Study Purpose

In this study, we evaluated sanitary survey data reported to SDWIS by states, the District of Columbia, tribes, and US-governed territories, with the objective of identifying the elements associated with the most frequent deficiencies and recommendations. SDWIS was queried for completed sanitary surveys, with visit dates ranging from Jan. 1, 2010, to Dec. 31, 2017. This date range was chosen to account for the effects of the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) and the Stage 2 Disinfectants and Disinfection Byproducts Rule (DBPR), both of which first became effective in 2009.

Analysis was limited to records from subpart H systems reported in 48 states and the District of Columbia. Two additional primacy agencies did not report any deficiencies and/or recommendations and were excluded. Records from inactive systems were also excluded. The resulting data set contains nearly 49,000 records from 14,550 PWSs (11,448 community and 3,102 non-community), serving more than 214 million people.

Sanitary Survey Data and Methods

SDWIS offers the most comprehensive data available on sanitary surveys on a national scale. The information is stored in tables with a record (row) for each sanitary survey, with columns containing water system identifiers (e.g., water system ID, name, state), survey dates, findings arranged by survey element, and a comment field. Each record contains survey findings in separate fields for each survey element, and more than 95% of the fields are populated.

Although there are only eight comprehensive elements per EPA requirements and accompanying guidance (EPA 2019, 2008, 1999), SDWIS uses 11 fields to describe the eight sanitary survey elements. Figure 1 presents a crosswalk of the eight sanitary survey elements (“eight elements”) and the 11 corresponding fields in SDWIS (“SDWIS elements”). Moreover, the monitoring and reporting element corresponds to “data verification” in SDWIS. For the purposes of this analysis, the additional fields of security, financial, and other evaluations were evaluated as subcategories within the management and operations sanitary survey element.

Figure 1. Crosswalk of Sanitary Survey Elements in SDWIS.

SDWIS–US Environmental Protection Agency Safe Drinking Water Information System

There are several survey finding options allowed in SDWIS under each of the 11 element fields: significant deficiencies, minor deficiencies, recommendations, not evaluated, not applicable, and an option to leave the element field blank.

Data Set Representativeness

The number of sanitary surveys extracted from SDWIS available after data filtering was compared with the system inventory available in SDWIS for the fourth quarter of 2017 for the same 48 states and the District of Columbia. The 14,550 systems with sanitary surveys in the data set represent approximately 90% (93.7% of community, 78% of non-transient non-community, and 80.4% of transient non-community) of the total SDWIS inventory of active surface water or GWUDI systems (16,105). The number of surveys reported per PWS ranged from one to 79, and on average, states reported more than three sanitary surveys per PWS during the eight-year period.

Some primacy agencies conduct and report their sanitary surveys in phases (e.g., by individual facilities) and/or as part of other assessments. Approximately 25% of systems had at least four surveys conducted during the years reviewed in this analysis. The number of surveys reported may also be influenced by increased frequency requirements set by the primacy agency, or partial reports marked as “complete.” Sanitary surveys used to meet requirements under the Revised Total Coliform Rule (RTCR; EPA 2013), or RTCR-related assessments used to partially complete sanitary surveys, may have also contributed to more reports than expected for the years of data for which the RTCR was effective. Additionally, some details from sanitary surveys may not be available within SDWIS, which may add complexity to reporting and factors into representativeness as well.

Primacy agencies using outstanding performer designations may also influence the representativeness of the underlying data set. Primacy agencies may reduce the frequency of conducting sanitary surveys for community water systems designated as outstanding performers to no less than every five years on the basis of prior positive sanitary survey results (40 CFR § 142.16(3)(ii))).

Analysis and Results

Two data sets were generated for analysis. The first data set was used to evaluate the designations under each of the SDWIS elements (referred to as the “element field” data set). The second data set (derived from the element-field data set) compiled the last two sanitary surveys from each water system conducted in the years 2010–2017 and was used to evaluate the comment field (referred to as the “comment field” data set).

Element-Field Data Set

The element-field data set contains nearly 49,000 sanitary survey records from 14,550 systems (Table 1). Surveys with significant deficiencies were distributed relatively evenly between community and non-community systems. Surveys with minor deficiencies and those with recommendations were reported more commonly in community than non-community systems. Sanitary surveys with minor deficiencies were the most common in the data set (making up approximately 28% of all surveys), followed by surveys with recommendations (approximately 24%) and surveys with significant deficiencies (approximately 11%).

Table 1.

Counts of Completed Sanitary Surveys for Subpart H Systems With Deficiencies or Recommendations in SDWIS by System Type, 2010–2017^a

System Type	Total Systems n	Total Surveys n	Total Surveys With Significant Deficiencies n (%)	Total Surveys With Minor Deficiencies n (%)	Total Surveys With Recommendations Made n (%)
Community	11,448	40,296	4,457 (11.1)	12,103 (30.0)	10,055 (25.0)
Non-transient non-community	768	1,898	175 (9.2)	394 (20.8)	384 (20.2)
Transient non-community	2,334	6,484	617 (9.5)	1,029 (15.9)	1,037 (16.0)
Total	14,550	48,678	5,249 (10.8)	13,526 (27.8)	11,476 (23.6)

SDWIS—US Environmental Protection Agency Safe Drinking Water Information System

^aIf a survey contained multiple deficiencies or recommendations, it was counted once when creating the summary table.

For all further analysis of the SDWIS data in this study, only those records identified in Table 1 containing deficiencies (significant or minor) and/or recommendations under one or more of the 11 SDWIS elements were included. By considering only the surveys with these designations, sanitary survey assessment areas that are receiving the most deficiencies and recommendations can be identified.

To determine the sanitary survey elements with the most occurrences of significant deficiencies, we compared the percentage of significant deficiencies within the 11 SDWIS element fields and separated results by population-served bins (Figure 2). The number of systems reporting surveys within each population bin is reported on the x-axis. Two systems in the data set reported different populations served across their surveys with significant deficiencies, and in those cases, the population served was assigned from the most recent survey provided. For presentation purposes, surveys were labeled from both non-transient and transient non-community water systems as “non-community water systems.”

Figure 2. Distributions of Significant Deficiencies^a by System Type and Size, 2010–2017.

ops–operations

^aSignificant deficiencies may have been identified under more than one element. Not all elements in the key had sufficient deficiencies to be visible in this figure (e.g., security, financial).

Among the 5,249 surveys with significant deficiency findings, the most common deficiencies for all water system types pertain to finished water storage, data verification (i.e., monitoring and reporting “element”), and treatment. The percentage of significant deficiencies associated with finished water storage increased with system size for community water systems. Conversely, the percentage of significant deficiencies associated with data verification decreased with system size. These findings are likely influenced by PWS characteristics. For instance, large systems tend to have more storage facilities relative to small systems, and small systems may lack technical, managerial, and financial capacity, which can affect the data verification element. The proportion of significant deficiencies under the distribution element was similar across population-served bins for community water systems, but the proportion increased with system size for non-community water systems.

A similar review of minor deficiencies and recommendations showed that the percentages (and distribution) of surveys with minor deficiencies and recommendations largely paralleled those for significant deficiencies. There was less heterogeniety across elements, and the percentages follow the same trends with respect to system size as significant deficency observations.

Comment-Field Data Set

The comment-field data set was assembled by reducing the element-field data set to a size that allowed for manual review. Because of the time-intensive nature of manually reviewing records, reviewing the comment field for all sanitary surveys in the data set was infeasible. Therefore, the last two surveys conducted by each subpart H system were manually analyzed, an approach that ensured at least two surveys per system were considered from time periods after the LT2ESWTR (EPA 2006b) and the Stage 2 DBPR (EPA 2006c) became effective. Records with no results in the comment field were removed from further analysis. The resulting comment-field data set contained 1,039 survey comments from 802 systems (615 community, 59 non-transient non-community, and 128 transient non-community) in 34 states. Comments reported in this data set were reviewed independently to determine if they were provided for a significant deficiency, minor deficiency, or recommendation.

A list of categories was developed to encompass a range of topics relevant to sanitary conditions and operational issues—e.g., repeated breaks or insufficient pressure in the distribution system; inadequate follow-up on previous deficiencies (see Table 2). The categories were developed prior to evaluating the comment field using best professional judgment and the available information on sanitary deficiencies within the guidance for subpart H systems (EPA 2019, 1999). Each category represents an issue that might indicate a deficiency or recommendation. These categories were then manually assigned to each comment on the basis of text in the comment field. Comments with text that fell outside the scope of these categories were marked as “uncategorized issues.”

Table 2.

Top 10 Most Common Sanitary Survey Deficiency Categories^a for Subpart H Systems

Deficiency Category Description	SDWIS Element	Surveys With Category Assignment n (% of all surveys)b
Unprotected existing or potential cross-connections	Other	280 (26.9)
Failure to monitor according to system’s monitoring plan(s) or established procedures	Data verification	238 (22.9)
Breakdown of treatment equipment or lack of redundancy	Treatment	167 (16.1)
System storage is incorrectly sized or has design issues	Finished water storage	136 (13.1)
Out-of-date emergency response plan	Security	123 (11.8)
Uncategorized issues	NA	111 (10.7)
Inadequate source water intake construction/condition	Source water	110 (10.6)
No storage tank cleaning, inspection, and maintenance program	Finished water storage	107 (10.3)
System components are not securely protected, and/or security alarms are not functional	Security	99 (9.5)
Designated operator is not certified at the grade required	Operator compliance	70 (6.7)

NA—not applicable, SDWIS—US Environmental Protection Agency Safe Drinking Water Information System

^aCategories were assigned on the basis of comment field.

^bPercentages are derived by taking the number of survey comments containing information on the categories (third column) and dividing by the total number of survey comments evaluated (1,039). As some surveys contain comments relating to more than one category, the percentages may add up to more than 100%.

The comments contained information relevant to all categories, with some issues being more common than others. Some survey comments represented multiple issues and were assigned more than one category. Table 2 presents summary information on 10 categories that were assigned most frequently to the comments, in descending order.

Next, we looked at records in the comment-field data set to see if that survey had also been marked as having deficiencies or recommendations. After counting how many times each category appeared in the comments, the counts were aggregated on the basis of the 11 SDWIS elements assigned to the categories. Only the category on cross-connections was developed under the “other” SDWIS element, which is labeled as “cross-connections” for presentation purposes. Figure 3 shows how often categories in each element area were mentioned in the survey comments (represented by the count on the y-axis). When a category was assigned to a comment, the record was examined to see if that survey had also been marked as having deficiencies or recommendations in the category’s respective SDWIS element field (see legend). For example, more than 200 issues related to security are described in the comment field, but most of those surveys do not have deficiencies or recommendations made in the “security” element field.

Figure 3. Number of Categorized Issues^a Arranged by SDWIS Element, Layered With Element Field Finding.

ops–operations, SDWIS–US Environmental Protection Agency Safe Drinking Water Information System

^aCategorized issues were assigned on the basis of comment field.

For the comment-field analysis, the most prevalent comments were related to data verification, cross-connections, and finished water storage. Compared with the element-field analysis, a larger proportion of comments contained information related to security and cross-connections. Finished water storage, data verification, source water, and treatment had the greatest number of deficiencies (in the element field), with corresponding issues indicated in comments.

When issues were identified in the comments, there were not always designations in the element field indicating a need for improvement in that area. These differences are represented by the teal coloring in Figure 3, where no deficiencies or recommendations are reported in the element field. For example, comments related to cross-connections were found in both treatment and distribution areas; however, the only category on cross-connections was placed under the “other” SDWIS element. Some surveyors identifying cross-connection issues in the comment field may have also indicated those deficiencies in the treatment and distribution system element fields.

Additional Considerations

In this analysis, we found that useful information was provided in both the SDWIS element fields and comment fields, and that taken together, these two information sources provided a more comprehensive understanding of common deficiencies. Reviewing surveys with deficiencies and recommendations provided valuable insight on specific water system and operational issues and is also meaningful when used at the primacy agency level. For example, Oxenford and Williams (2014) evaluated sanitary survey data in SDWIS for Colorado community water systems, and distribution system and treatment-related deficiencies were the top two failures requiring corrective actions.

Our analysis of the SDWIS element-field data set indicated that most significant deficiencies pertain to the elements of finished water storage, data verification, and treatment. After reviewing the comment-field data set, most of the issues described in comments were found to be associated with data verification, cross-connections, finished water storage, security, treatment, and source water. Some issues in the comments were not designated with deficiencies or recommendations in the respective element field; this dissimilarity may be due to differences in primacy agency or individual surveyor reporting practices.

Program Implementation Considerations

Considering the representativeness of the SDWIS data set, it is reasonable to conclude that this analysis reveals broad-issue areas in water systems. However, it’s important to recognize that the findings could be influenced by differences in PWS characteristics and sanitary survey programs across primacy agencies. Variation across primacy agency information on significant deficiencies was apparent in online searches; for example, a comparison of significant deficiency lists for finished water storage on two state websites showed that leaks were considered significant deficiencies in one state but not explicitly by the other. Surveyors also choose different words to describe similar deficiencies. These differences add uncertainty when comparing deficiencies and recommendations across programs. In addition, the time period of data considered for this evaluation (i.e., 2010–2017) does not reflect recent challenges experienced by PWSs such as with extreme weather and cybersecurity attacks.

As discussed, primacy agencies have flexibility in developing, implementing, and administering their sanitary survey programs, which influences the SDWIS data available for analysis. The use of electronic tools for conducting sanitary surveys, such as tablets and cell phones, is changing how surveys are being conducted and reported, potentially allowing for quicker and streamlined reporting. Furthermore, drone technology is being used during sanitary surveys to collect real-time images and video of storage facility rooftops and other remote locations that are otherwise difficult to access and inspect (AT&T 2019).

Some primacy agencies use applications on desktops or mobile devices to complete sanitary survey reports, whereas others are paper based. In addition to improving efficiency, electronic tools may improve communication between PWSs and states, which may have positive outcomes for public health protection and allow for quicker identification, response, and correction to any possible issues.

Proactive Protection of Public Health

In the United States, sanitary surveys are an important tool used by primacy agencies and water systems to proactively protect public health. Broadly evaluating sanitary survey findings and common deficiencies may also help primacy agencies assess and prioritize water system infrastructure issues and utility training needs. For example, some sanitary survey elements identified as areas of concern in this study, such as treatment or finished water storage, also make up a large amount of water system infrastructure funding needs nationwide (EPA 2018).

Primacy agencies that choose to conduct more detailed evaluations of deficiencies found in water systems under their authority may benefit from the methods introduced in this study. Similar analyses at the state and/or utility level may be helpful in improving operations and maintenance practices and identifying and prioritizing capital projects to better manage sanitary risks. These analyses are relevant when looking across states (as was done in this analysis) and could be helpful for states looking within their programs or at specific types and sizes of systems, for example, focusing on smaller community or non-community water systems for certain types of deficiencies.

Within a framework of sanitary survey rule requirements, such as addressing the eight elements or responding to significant deficiencies, primacy agencies are given latitude in how they can conduct the surveys and assign deficiencies. Furthermore, significant deficiencies that go uncorrected may result in drinking water rule violations and adverse public health consequences. An in-depth analysis of these deficiencies could identify underlying causes of violations and help regulators improve SDWA compliance. Programs such as EPA’s Area Wide Optimization Program (EPA 2017b) provide compliance assistance to water systems and may help to address issues in the areas of treatment and distribution that could be identified as deficiencies during sanitary surveys.

Key Takeaways.

Sanitary survey data can be broadly evaluated to understand the most prevalent issues occurring within public water systems.

The most commonly identified deficiencies are associated with monitoring and reporting, finished water storage, and treatment.

Reviewing sanitary survey findings and common deficiencies may help officials proactively determine water system infrastructure issues and utility training needs.