This comment letter response contains two parts:   

(1) The original submittal from the commenter.

(2) A data base printout of EPA’s response to each point raised by the commenter.

Notes about the response letters:

• The response letters were generated by a data base used to track the content of all public

comment submittals and ensure that the Agency responds to each. Each comment letter

was assigned a Letter ID that corresponds to the last four digits of the docket number of the

original comment (as posted on www.regulations.gov).

• Each response letter includes: comment text; an EPA‐assigned comment code; and an

individual response. These are described and explained below.  

• The data base contains Comment text from the letters submitted by commenters.  

Many hard copy letters were scanned into electronic format for inclusion in the data

base. As a result, there may be some typographical errors attributable to optical

character recognition issues.  However, all original submittals were reviewed in the

process of drafting responses to ensure that the comment content was understood and

appropriately addressed.

• The content of each comment letter was divided into topic areas and assigned a unique

Comment ID.  Additionally, one or more Comment Codes (i.e., unique topic area ID) was

assigned to each discrete point raised by a commenter. This information was added to

the data base. To inform final rulemaking decisions, all comments and information

received on a given topic were reviewed by technical experts in each rule area (e.g., on

construction requirements).  

• Following decisions on the final rule requirements, Individual responses were drafted

by topic area to ensure completeness and consistency of the responses with the final

rule and other responses to similar comments.  Each discrete point made by a

commenter was given a unique response.

• Upon completion of comment responses, all information was entered into the data base.

Each letter response is a compilation of each comment and its individual response,

compiled in the order of the original comment letter.  As a result of this process, there is

repetition in the response text.  The Agency believes this approach ensures completeness

and attention to each comment letter that was submitted.   

• All comments in a topic area were reviewed, evaluated, and responded to concurrently.  

Responses on each topic area are compiled and are also available in the rulemaking docket.
- 0 W -Z66ib:10a~ 7 61 

MWD 

METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA 

December 23, 2008 

Attention: Docket ID Number EPA-HQ-OW-2008-0390 

OSWER Docket 

EPA Docket Center Mailcode: 2822T 

Environmental Protection Agency 

1200 Pennsylvania Ave., NW 

Washington, DC 20460 

Dear Environmental Protection Agency: 

JAN 0 ,5 2009 

Comments on Federal Requirements Under the Underground Injection Control Program for 

Carbon Dioxide (C02) Geologic Sequestration Wells 

The Metropolitan Water District of Southern California (Metropolitan) is submitting comments on 

U.S . Environmental Protection Agency's (EPA) proposed Federal requirements under the Safe 

Drinking Water Act (SDWA) for underground injection of C02 for the purpose of geologic 

sequestration (40 Federal Register 43492). This potential practice to mitigate the effects of 

greenhouse gas emissions raises the concern of potential contamination to underground sources of 

drinking water, particularly sole-source aquifers. Other concerns include unproven technology to 

be used for injection wells, undefined water rights between states sharing a single underground 

source of water, and unresolved long-term liability and financial responsibility for sequestration 

sites . We appreciate EPA's efforts to address this urgent environmental concern and hope these 

comments will assist in protecting the needs of drinking water utilities and their customers. 

Metropolitan is a regional water supply agency that provides supplemental water to nearly 18 

million people throughout the southern California area. Our two major sources of supply are the 

Colorado River and the California State Water Project utilizing water from the San Joaquin -

Sacramento River Bay Delta. While Metropolitan does not own or operate groundwater wells as 

part of its water supply operation, approximately 37% of the annual retail demands for water in our 

service area depend on local and regional groundwater supplies . Metropolitan and other agencies 

store surplus water in various groundwater basins throughout California for use during dry years. 

Metropolitan and the agencies it serves depend heavily on the viability of these important 

groundwater basins to produce the balance of regional supply needs. 

We would specifically ask that EPA not implement any geologic sequestration pilot program in a 

groundwater basin that is the sole source of supply for an urban area. Unproven commercial-scale 

geologic carbon sequestration technology may pose unintended impacts on groundwater basins and 

potentially compromise both water quality and water supply . 
Docket ID Number EPA-HQ-OW-2008-0390 

Page 2 

December 24, 2008 

The American Water Works Association (AWWA) has provided testimony and extensive written 

comment of this proposed regulation. The new class of injection well proposed under this rule 

specifically for injecting C02 into deep, underground geologic formations is a source of primary 

concern for AWWA because of the potential contamination of underground sources of drinking 

water, particularly sole source aquifers, and the unintended, possibly harmful, consequences. 

Metropolitan shares this concern and joins with AWWA in the call to mitigate these concerns prior 

to any final rulemaking. 

While Metropolitan and the drinking water industry support meaningful efforts to reduce 

greenhouse gas emissions, it is our hope that any gain in these reductions does not come at the 

expense of vital drinking water supplies. Metropolitan appreciates this opportunity to provide 

comment and asks that EPA carefully consider these comments as well as those by AWWA and 

other drinking water concerns. Please contact me at (213) 217-5696 if you have any questions, or if 

I can provide additional information. 

Very truly yours, 

Mic Stewart, PhD 

Manager, Water Quality Section 
Letter ID: 0279 

Commenter: Mic Stewart 

Organization: Metropolitan Water District of Southern California 

Letter ID: 0279 Comment ID: 24093 Letter Lines: 38 to 40 

Comment Code: 1610 1.3.1 Risks to USDWs 

Comment: 43492). This potential practice to mitigate the effects of greenhouse gas 

emissions raises the concern of potential contamination to underground sources of 

drinking water, particularly sole-source aquifers. Other concerns include 

Individual Response: The Agency agrees that drinking water is an important resource to 

protect. The primary goal of the UIC Program under the SDWA is to protect USDWs from 

endangerment. Consistent with SDWA §1422, the UIC program provides that no injection shall 

be authorized if it results in the movement of fluid containing any contaminant into USDWs, if 

the presence of that contaminant may cause a violation of any primary drinking water regulation 

or may adversely affect the health of persons as specified in §144.12. 

The GS rule, as part of the UIC program regulations, continues the Program’s mandate under the 

SDWA of ensuring the protection of USDWs from endangerment. EPA expects that the tailored 

permitting, siting, construction, operation, monitoring, and post-injection site care requirements 

in the GS rule to prevent leakage from injection formations and protect USDWs. 

The GS rule, at §146.82(a)(5) requires prospective owners or operators to submit information on 

all USDWs within the AoR. EPA expects that this information will include identification of any 

sole source aquifers. The GS rule also requires operators to submit extensive information about 

the site, including the geologic characteristics of the injection and confining zones, to 

demonstrate that the injected CO2 will remain within the target formation. The Director must 

consider this information when determining whether GS is acceptable at a given site. EPA 

expects that during this evaluation the Director will consider the potential impact of the GS 

project on any sole source aquifers. 

Letter ID: 0279 Comment ID: 24094 Letter Lines: 40 to 43 

Comment Code: 1310 1.1.2.4 Comments on other "out of scope" issues, e.g., pore space 

ownership 

Comment Code: 5400 2.9 Proposed Financial Responsibility and Long-Term Care 

Requirements 

Comment: drinking water, particularly sole-source aquifers. Other concerns include 

unproven technology to be used for injection wells, undefined water rights 

between states sharing a single underground source of water, and unresolved 

long-term liability and financial responsibility for sequestration sites. We 

1
Individual Response: EPA clarifies that subsurface property rights, including water rights, are 

outside the scope of the GS rulemaking. 

Under SDWA authority, owners or operators of injection wells must ensure protection of 

USDWs from endangerment and are subject to liability for enforcement under the Act. The final 

rule requires that an owner or operator must conduct monitoring as specified in the Directorapproved PISC and site closure plan following the cessation of injection until the owner or 

operator can demonstrate to the Director that the geologic sequestration project no longer poses 

an endangerment to USDWs. For additional information about the PISC and site closure 

requirements, see the preamble to the final GS rule. 

Once an owner or operator has met all regulatory requirements under Part 146 for Class VI wells 

and the Director has approved site closure pursuant to requirements at §146.93, the owner or 

operator will generally no longer be subject to enforcement for regulatory noncompliance. 

Furthermore, their financial instrument as required under §146.85 will be released if it was not 

used. However, even if a site closure is approved under §146.93, an owner or operator may be 

held liable for regulatory noncompliance (including violation of 40 CFR 144.12) in certain 

circumstances. For example, an owner or operator may be held liable for regulatory 

noncompliance even after site closure was approved if the Director relied on erroneous 

information (e.g., erroneous modeling data) provided by the owner or operator when approving 

site closure. 

Additionally, an owner or operator may always be subject to any action the Administrator deems 

necessary to protect the health of persons under §1431 of the SDWA after site closure if there is 

unanticipated migration towards or into a USDW that causes or threatens imminent and 

substantial endangerment to public health. The action may include issuing administrative orders 

or commencing a civil action for appropriate relief. If the owner or operator fails to comply with 

the order, they may be subject to a civil penalty for each day in which such violation occurs or 

failure to comply continues. 

The Agency clarifies that Class VI well permits may be transferred to another owner or operator 

pursuant to §144.38 whereby generally all other regulatory responsibilities are transferred to that 

new owner and operator, which includes all potential liabilities associated with meeting the 

requirements of that permit. Please see further clarification on the issue of long term liability in 

the preamble of the final rule. 

Furthermore, after site closure an owner or operator may remain liable under tort and other 

remedies, or under other federal statutes including, but not limited to, Clean Air Act, 42 U.S.C. 

§§ 7401-7671; CERCLA, 42 U.S.C. § 9601-9675; and RCRA, 42 U.S.C. § 6901-6992. EPA 

does not have authority to transfer SDWA or other legal liability for Class VI wells to the State 

or federal government or a third-party fund. See the final rule preamble for further discussion of 

EPA's final approach. 

Letter ID: 0279 Comment ID: 24095 Letter Lines: 51 to 77 

Comment Code: 1610 1.3.1 Risks to USDWs 

2
Comment: Project utilizing water from the San Joaquin Sacramento River Bay Delta. While 

Metropolitan does not own or operate groundwater wells as part of its water 

supply operation, approximately 37% of the annual retail demands for water in our 

service area depend on local and regional groundwater supplies. Metropolitan and 

other agencies store surplus water in various groundwater basins throughout 

California for use during dry years. Metropolitan and the agencies it serves 

depend heavily on the viability of these important groundwater basins to produce 

the balance of regional supply needs. 

We would specifically ask that EPA not implement any geologic sequestration 

pilot program in a groundwater basin that is the sole source of supply for an 

urban area. Unproven commercial-scale geologic carbon sequestration technology 

may pose unintended impacts on groundwater basins and potentially compromise 

both water quality and water supply. 

The American Water Works Association (AWWA) has provided testimony and extensive 

written comment of this proposed regulation. The new class of injection well 

proposed under this rule specifically for injecting CO2 into deep, underground 

geologic formations is a source of primary concern for AWWA because of the 

potential contamination of underground sources of drinking water, particularly 

sole source aquifers, and the unintended, possibly harmful, consequences. 

Metropolitan shares this concern and joins with AWWA in the call to mitigate 

these concerns prior to any final rulemaking. 

While Metropolitan and the drinking water industry support meaningful efforts to 

reduce greenhouse gas emissions, it is our hope that any gain in these 

reductions does not come at the expense of vital drinking water supplies. 

Individual Response: The Agency agrees that drinking water is an important resource to 

protect. The primary goal of the UIC Program under the SDWA is to protect USDWs from 

endangerment. Consistent with §1422, the UIC program provides that no injection shall be 

authorized if it results in the movement of fluid containing any contaminant into USDWs, if the 

presence of that contaminant may cause a violation of any primary drinking water regulation or 

may adversely affect the health of persons as specified in §144.12. 

The GS rule, as part of the UIC program regulations, continues the Program’s mandate under the 

SDWA of ensuring the protection of USDWs from endangerment. EPA expects that the tailored 

permitting, siting, construction, operation, monitoring, and post-injection site care requirements 

in the GS rule will prevent leakage from injection formations and protect USDWs. 

The GS rule, at §146.82(a)(5) requires prospective owners or operators to submit information on 

all USDWs within the AoR. EPA expects that this information will include identification of any 

sole source aquifers. The GS rule also requires operators to submit extensive information about 

the site, including the geologic characteristics of the injection and confining zones, to 

demonstrate that the injected CO2 will remain within the target formation. The Director must 

3
consider this information when determining whether GS is acceptable at a given site. EPA 

expects that during this evaluation the Director will consider the potential impact of the GS 

project on any sole source aquifers. 

EPA recognizes that injecting large volumes of CO2 for GS poses unique challenges and risks 

that, if not properly managed, could endanger drinking water sources or have other adverse 

impacts. EPA agrees that caution is warranted and has, as a result, developed a new well class 

with requirements tailored to address the unique challenges posed by GS and potential risks 

associated long-term injection of CO2. These requirements include the tailored AoR delineation 

process per §146.84, monitoring that is appropriate to GS projects per §146.90, and extended 

post-injection site care per §146.93. 

Letter ID: 0279 Comment ID: 24096 Letter Lines: 78 to 80 

Comment Code: 1000 1. General and Administrative Comments 

Comment: Metropolitan appreciates this opportunity to provide comment and asks that EPA 

carefully consider these comments as well as those by AWWA and other drinking 

water concerns. Please contact me at (213) 217-5696 if you have any questions, 

Individual Response: EPA acknowledges the comment. Please see the remainder of EPA's 

responses to this comment letter and AWWA’s comment for further details. For additional 

information on EPA's final regulatory approach, please see the final rule and preamble as well as 

the rulemaking docket. 

4