Regulatory Flexibility Act Section 610 Review of the National Primary Drinking Water Regulations: 

Ground Water Rule

United States Environmental Protection Agency

Office of Water

April 1, 2016

Results of Section 610 Review of the Ground Water Rule

BACKGROUND

On November 8, 2006 (71 FR 65573), the EPA promulgated the National Primary Drinking Water 

Regulations: Ground Water Rule as authorized by the Safe Drinking Water Act (SDWA). In this action, 

referred to as the Ground Water Rule (GWR), the EPA promulgated sanitary survey, source water 

monitoring, treatment technique and compliance monitoring requirements. The GWR became effective 

on January 8, 2007.

Before the GWR was promulgated, the EPA developed a Regulatory Flexibility Analysis and took several 

steps to lessen the impacts on small entities. These steps included: (1) selecting a targeted approach, 

requiring corrective action (e.g., disinfection) only for high risk systems or sources that are vulnerable to 

contamination; (2) allowing state flexibility to make the GWR less burdensome by permitting Total 

Coliform Rule (TCR) source water repeat samples to satisfy GWR triggered source water monitoring 

requirements; (3) minimizing burden by promulgating monitoring requirements based on system 

characteristics (risk) rather than on system size; and (4) allowing states to consider the characteristics of 

an individual system when determining an appropriate corrective action.

Section 610 of the Regulatory Flexibility Act (RFA) requires federal agencies to review regulations that 

have significant economic impact on a substantial number of small entities within 10 years of their 

adoption as final rules. Pursuant to this requirement, the EPA has reviewed this rule to determine if it 

should be continued without change, or should be rescinded or amended to minimize adverse impacts 

on small entities. This review was announced in the Regulatory Agenda, which was published in the 

Federal Register on December 15, 2015 (80 FR 78024). As part this review, the EPA considered and 

solicited comment on the following factors: (1) the continued need for the rule; (2) the nature of 

complaints or comments received concerning the rule; (3) the complexity of the rule; (4) the extent to 

which the rule overlaps, duplicates, or conflicts with other federal, state, or local government rules; and 

(5) the degree to which technology, economic conditions, or other factors have changed in the area 

affected by the rule.

The EPA received three comment letters in response to the December 15, 2015, Federal Register notice. 

One additional submission appeared to be a duplicate response. All the letters are available for public 

inspection in the rulemaking docket (docket number EPA-HQ-OW-2015-0541 at www.regulations.gov). 

The results of the EPA’s Section 610 review of the Ground Water Rule are presented in this report.

Discussion of Factors Required by Section 610 of the Regulatory Flexibility Act

1. Continued need for the rule.
Two of the commenters suggested there was a clear and continued need for the rule. They identified 

multiple GWR elements that remain key to providing safe drinking water, including targeted monitoring 

for bacteria. According to these two commenters, the GWR is beneficial because the rule provides: 1) 

state flexibility to incorporate program activities to meet state-specific needs; 2) source water 

monitoring to characterize well water quality; and 3) regulatory authority to require correction of 

significant deficiencies. 

The other commenter stated that the GWR has outlived its usefulness, despite a previous initial 

beneficial effect. This commenter suggested that the GWR now only results in unnecessary 

bacteriological testing. 

The agency believes that the GWR continues to provide essential protection. For example, bacterial 

monitoring is a key element of a multi-barrier approach for public health protection, especially for 

ground water that has not been disinfected. The EPA concludes that such testing is necessary and 

appropriate. Hence, the agency agrees with the viewpoint that there is a clear and continued need for 

the rule.

2. Nature of complaints or comments received concerning the rule.

There were two main issues for which commenters requested that the rule be amended to ease the 

burden on small systems. Both issues are associated with triggered monitoring when a total coliform is 

detected under the TCR or the Revised Total Coliform Rule (RTCR)1. The TCR/RTCR and GWR are 

designed to complement each other, and therefore reduce monitoring costs. Monitoring required under 

the TCR/RTCR is the trigger for some actions required under the GWR. For instance, source water GWR 

monitoring is required only if a TCR/RTCR sample is total coliform positive. 

Two commenters report an apparent prevalence of routine total coliform positive occurrence. 

According to the commenters, these detections add cost because a positive sample requires additional 

source water samples. Both commenters believe that this single, unconfirmed occurrence is too 

sensitive a trigger; one commenter believes that a better choice is either a confirmed total coliform 

positive or an E. coli occurrence; the other commenter suggests triggering only when a sample is E. coli

positive. 

During the GWR rulemaking process, the EPA took public comment on the triggered monitoring 

provisions in the proposed rule. Based on those comments, the EPA revised the proposed rule to reduce 

the cost to the regulated community prior to promulgating the final rule. The EPA recognized that total 

coliform in undisinfected drinking water is an indicator of a potential contaminant pathway, but it is not 

in and of itself an indication of fecal contamination. As a result, under the GWR, total coliform 

occurrence results in additional sampling of the well(s) for fecal indicators (either E. coli, enterococci, or 

coliphage). The EPA recognizes that additional samples add burden, but the agency believes that these 

additional samples provide better information, which is useful to protect the public health of consumers 

using undisinfected public water systems (PWSs). Additional samples help ascertain whether the total 

 

1 The Revised Total Coliform Rule (RTCR) is a revision of the Total Coliform Rule. The RTCR became effective on 

April 15, 2013. Public water systems must begin compliance with the RTCR no later than April 1, 2016. The RTCR 

did not change the provisions for triggered source monitoring under the GWR.
coliform occurrence is a result of contaminant infiltration of the source water or whether there is some 

bacterial occurrence within the water distribution network. If the source of contamination is infiltration, 

it is considered a more serious issue because the infiltrating groundwater can entrain fecal 

contaminants such as bacterial and viral pathogens.

All commenters suggest that making changes to the GWR triggered monitoring target would better align

the GWR with the RTCR. The RTCR was promulgated after the GWR. Because the RTCR shifted focus to E. 

coli and away from fecal coliform, commenters suggest reducing total coliform monitoring in the GWR 

to reduce total burden and, in their opinions, better align the GWR with RTCR requirements. The EPA 

notes that the RTCR applies equally to all PWSs, both treated and untreated. The rule is designed to 

identify (and remediate) contaminant intrusion into distribution systems and contaminant occurrence. 

In contrast, the GWR triggered source water monitoring requirement applies only to untreated systems

or to systems that do not provide 4-log inactivation of viruses. Fecal indicator monitoring protects public 

health by identifying wells with potential contaminant pathways and contamination occurrence. 

Furthermore, many GWR systems are small with limited distribution systems. Because of these differing 

public health objectives and because the GWR and RTCR complement each other’s goals, the EPA does 

not believe that the recent RTCR changes necessitate GWR changes.

A second issue espoused by two commenters is the burden on consecutive systems when a routine

TCR/RTCR sample is total coliform positive. The GWR requires that all sources that serve the consecutive 

system must be tested for the presence of fecal indicators when a sample under the TCR/RTCR is total 

coliform positive. These two commenters state that it is significant burden to test each source. The EPA 

acknowledges the extra burden that results when multiple source water samples must be tested. 

However, for these undisinfected systems, sampling all ground water sources identifies which, if any, of 

the sources show evidence of a contaminant pathway so that potential issues can be addressed. This 

deductive approach generates actionable information that can be used to protect public health.

3. The complexity of the rule.

The EPA received comments that the GWR overlaps in part with the TCR/RTCR. In particular, 

commenters noted perceived overlap in needing to coordinate and track significant deficiencies under 

the GWR and sanitary defects under the RTCR. Commenters believe that the differing schedules 

associated in addressing significant deficiencies and sanitary defects may pose a challenge to achieving 

compliance with both rules. 

As discussed in the Public Comment and Response Document for the Revised Total Coliform Rule,

2

the 

advisory committee3specifically stated that “sanitary defects” are specific to the assessment and 

corrective action requirements of the RTCR and are not intended to be linked directly to “significant 

deficiencies” under the Interim Enhanced Surface Water Treatment Rule and the GWR, although some 

problems could meet either definition. The term “significant deficiency” is tied or associated with the 

eight elements of a sanitary survey. Accordingly, there are problems that are “sanitary defects” and are 

also “significant deficiencies” and vice versa. For instance, source water problems like those associated 

 

2 US EPA. Public Comment and Response Document for the Revised Total Coliform Rule. EPA815-R-12-014. 

December 2012.

3 EPA convened a Federal Advisory Committee to discuss the revisions to the Total Coliform Rule.
with the well casing may fit the definition of both a “sanitary defect” and a “significant deficiency.” 

Depending on when the problem was identified (i.e., during a sanitary survey or during an assessment 

triggered under RTCR) and on the nature of the problem, the state can set guidelines on how to 

characterize the problem and how systems can comply with both rules, if needed. Nothing in the RTCR is 

intended to limit the existing authorities of states under other regulations.

As discussed above, the TCR/RTCR and GWR are complementary rules and are designed to support each 

other. The EPA recognizes that there may be challenges in implementing both rules. The EPA tries to 

address simultaneous compliance with the RTCR and with the requirements of other drinking water 

rules such as the GWR in the RTCR Assessments and Corrective Actions Guidance Manual-Interim Final,4

State Implementation Guidance-Interim Final,5 and A Guide for Small Public Water Systems.6States also 

have the flexibility and multiple authorities to address issues under the two rules. This allows states to 

use system-specific knowledge to most effectively and expeditiously address issues. 

One commenter stated the difficulty for state approval of UV for 4-log virus inactivation. The 

commenter suggested that there remains insufficient information for states to approve UV inactivation 

as an alternative to chlorine disinfection for 4-log virus inactivation.

The EPA acknowledges the challenges for states tasked with approval of UV (instead of chlorination) for 

4-log virus inactivation. The UV validation process published in the Long Term 2 Enhanced Surface Water 

Rule UV Disinfection Guidance document7is appropriate for demonstrating 4-log virus inactivation for 

technologies with performance studies for adenovirus validation. However, the current guidance may 

not have the newest results and may require UV doses, hardware and energy burdens that may be too 

costly for small undisinfected ground water systems. The EPA continues to participate in UV work groups 

to find ways to verify 4-log virus inactivation using differing UV lamps in combination with a variety of 

virus targets, including adenovirus, hepatitis A and coxsackie A virus, which are especially resistant to UV 

inactivation. The UV workgroup continues to look at validation studies to reduce burden and to make 

UV available to smaller systems.

4. The extent to which rule overlaps, duplicates, or conflicts with other federal, state, or local 

government rules.

One commenter reiterated that the GWR deadlines for correction of significant deficiencies are different 

from the RTCR deadlines for sanitary defects. This putative conflict is believed to complicate state 

management of the two rules. The EPA anticipates experience gained from implementing both rules 

provides states with insight on more efficient ways to manage complementary components of both 

rules. Please see discussion above (item 3) about simultaneous rule compliance. 

 

4 US EPA. Revised Total Coliform Rule Assessments and Corrective Actions Guidance Manual – Interim Final. EPA 

815-R-14-006. September 2014.

5 US EPA. The Revised Total Coliform Rule (RTCR) State Implementation Guidance – Interim Final. EPA 816-R-14-

004. December 2014.

6 US EPA. The Revised Total Coliform Rule, A Guide for Small Public Water Systems. EPA 815-B-15-002. October 

2015.

7 US EPA. Ultraviolet Disinfection Guidance Manual for the Final Long Term 2 Enhanced Surface Water Treatment 

Rule. EPA 815-R-06-007. November 2007.
5. The degree to which technology, economic conditions, or other factors have changed in the area 

affected by the rule.

One commenter suggests that the newer technologies (membrane or UV) to achieve 4-log virus 

inactivation remain desirable but insufficiently demonstrated protective of public health. The EPA 

recognizes that continued information sharing with the states is key to state adoption and oversight of 

new technologies. The EPA continues to participate in workshops and to conduct research to better 

demonstrate the capability of the new technologies, especially the use of new lamps and virus targets 

for UV. For membrane technologies, state oversight of performance remains challenging because 

membrane integrity testing to show virus removal is impractical. Because many membranes are not 

capable of virus removal, states are challenged by conflicting and incomplete information. The EPA 

believes that continued information sharing about membranes and membrane integrity over time will 

assist state adoption and oversight procedures.

Conclusion

Most of the comments were aimed at suggesting that the agency make clarifications in certain areas of 

the GWR to aid small entities in rule compliance. After reviewing all the comments regarding this 

Regulatory Flexibility Act Section 610 Review, the agency has concluded that revisions or amendments 

to minimize economic impacts on small entities from the Ground Water Rule are not warranted at this 

time.

The EPA continues to view the Ground Water Rule component of the Nation Primary Drinking Water 

Regulations (NPDWR) as important to ensure and protect the health of consumers served by public 

drinking water systems and intends to continue to require compliance with this NPDWR. The agency 

also bases its decision to not revise or amend the rule at this time on the analysis conducted during the 

promulgation of the rule. Among other things, the rule included elements which were specifically 

designed to minimize economic burden on small entities. Among the measures that the agency took, at 

the time of rule promulgation, to minimize impacts on small entities are: (1) selecting a targeted 

approach, requiring corrective action (e.g. disinfection) only for high risk systems or sources that are 

vulnerable to contamination; (2) allowing state flexibility to make the GWR less burdensome by 

permitting TCR source water repeat samples to satisfy GWR triggered source water monitoring 

requirements; (3) minimizing burden by promulgating monitoring requirements based on system 

characteristics (risk) rather than on system size; and (4) allowing states to consider the characteristics of 

the individual system when determining an appropriate corrective action. The EPA believes these 

measures remain appropriate and minimize burden on small entities.