[Code of Federal Regulations]
[Title 40, Volume 19]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR141.71]

[Page 434-436]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 141--NATIONAL PRIMARY DRINKING WATER REGULATIONS--Table of Contents
 
                 Subpart H--Filtration and Disinfection
 
Sec. 141.71  Criteria for avoiding filtration.

    A public water system that uses a surface water source must meet all 
of the conditions of paragraphs (a) and (b) of this section, and is 
subject to paragraph (c) of this section, beginning December 30, 1991, 
unless the State has determined, in writing pursuant to 
Sec. 1412(b)(7)(C)(iii), that filtration is required. A public water 
system that uses a ground water source under the direct influence of 
surface water must meet all of the conditions of paragraphs (a) and (b) 
of this section and is subject to paragraph (c) of this section, 
beginning 18 months after the State determines that it is under the 
direct influence of surface water, or December 30, 1991, whichever is 
later, unless the State has determined, in writing pursuant to 
Sec. 1412(b)(7)(C)(iii), that filtration is required. If the State 
determines in writing pursuant to Sec. 1412(b)(7)(C)(iii) before 
December 30, 1991, that filtration is required, the system must have 
installed filtration and meet the criteria for filtered systems 
specified in Secs. 141.72(b) and 141.73 by June 29, 1993. Within 18 
months of the failure of a system using surface water or a ground water 
source under the direct influence of surface water to meet any one of 
the requirements of paragraphs (a) and (b) of this section or after June 
29, 1993, whichever is later, the system must have installed filtration 
and meet the criteria for filtered systems specified in Secs. 141.72(b) 
and 141.73.
    (a) Source water quality conditions. (1) The fecal coliform 
concentration must be equal to or less than 20/100 ml, or the total 
coliform concentration must be equal to or less than 100/100 ml 
(measured as specified in Sec. 141.74 (a) (1) and (2) and (b)(1)), in 
representative samples of the source water immediately prior to the 
first or only point of disinfectant application in at least 90 percent 
of the measurements made for the 6 previous months that the system 
served water to the public on an ongoing basis. If a system measures 
both fecal and total coliforms, the fecal coliform criterion, but not 
the total coliform criterion, in this paragraph must be met.
    (2) The turbidity level cannot exceed 5 NTU (measured as specified 
in Sec. 141.74 (a)(4) and (b)(2)) in representative samples of the 
source water immediately prior to the first or only point of 
disinfectant application unless: (i) the State determines that any such 
event was caused by circumstances that were unusual and unpredictable; 
and (ii) as a result of any such event, there have not been more than 
two events in the past 12 months the system served water to the public, 
or more than five events in the past 120 months the system served water 
to the public, in which the turbidity level exceeded 5 NTU. An ``event'' 
is a series of consecutive days during which at least one turbidity 
measurement each day exceeds 5 NTU.
    (b) Site-specific conditions. (1)(i) The public water system must 
meet the requirements of Sec. 141.72(a)(1) at least 11 of the 12 
previous months that the system served water to the public, on an 
ongoing basis, unless the system fails to meet the requirements during 2 
of the 12 previous months that the system served water to the public, 
and the State determines that at least one of these failures was caused 
by circumstances that were unusual and unpredictable.
    (ii) The public water system must meet the requirements of 
Sec. 141.72(a)(2) at all times the system serves water to the public.
    (iii) The public water system must meet the requirements of 
Sec. 141.72(a)(3) at all times the system serves water to the public 
unless the State determines that any such failure was caused by 
circumstances that were unusual and unpredictable.
    (iv) The public water system must meet the requirements of 
Sec. 141.72(a)(4) on an ongoing basis unless the State determines that 
failure to meet these requirements was not caused by a deficiency in 
treatment of the source water.
    (2) The public water system must maintain a watershed control 
program which minimizes the potential for contamination by Giardia 
lamblia cysts and viruses in the source water. The State must determine 
whether the watershed control program is adequate to meet this goal. The 
adequacy of a program to limit potential contamination by Giardia 
lamblia cysts and viruses must

[[Page 435]]

be based on: the comprehensiveness of the watershed review; the 
effectiveness of the system's program to monitor and control detrimental 
activities occurring in the watershed; and the extent to which the water 
system has maximized land ownership and/or controlled land use within 
the watershed. At a minimum, the watershed control program must:
    (i) Characterize the watershed hydrology and land ownership;
    (ii) Identify watershed characteristics and activities which may 
have an adverse effect on source water quality; and
    (iii) Monitor the occurrence of activities which may have an adverse 
effect on source water quality.
    The public water system must demonstrate through ownership and/or 
written agreements with landowners within the watershed that it can 
control all human activities which may have an adverse impact on the 
microbiological quality of the source water. The public water system 
must submit an annual report to the State that identifies any special 
concerns about the watershed and how they are being handled; describes 
activities in the watershed that affect water quality; and projects what 
adverse activities are expected to occur in the future and describes how 
the public water system expects to address them. For systems using a 
ground water source under the direct influence of surface water, an 
approved wellhead protection program developed under section 1428 of the 
Safe Drinking Water Act may be used, if the State deems it appropriate, 
to meet these requirements.
    (3) The public water system must be subject to an annual on-site 
inspection to assess the watershed control program and disinfection 
treatment process. Either the State or a party approved by the State 
must conduct the on-site inspection. The inspection must be conducted by 
competent individuals such as sanitary and civil engineers, sanitarians, 
or technicians who have experience and knowledge about the operation and 
maintenance of a public water system, and who have a sound understanding 
of public health principles and waterborne diseases. A report of the on-
site inspection summarizing all findings must be prepared every year. 
The on-site inspection must indicate to the State's satisfaction that 
the watershed control program and disinfection treatment process are 
adequately designed and maintained. The on-site inspection must include:
    (i) A review of the effectiveness of the watershed control program;
    (ii) A review of the physical condition of the source intake and how 
well it is protected;
    (iii) A review of the system's equipment maintenance program to 
ensure there is low probability for failure of the disinfection process;
    (iv) An inspection of the disinfection equipment for physical 
deterioration;
    (v) A review of operating procedures;
    (vi) A review of data records to ensure that all required tests are 
being conducted and recorded and disinfection is effectively practiced; 
and
    (vii) Identification of any improvements which are needed in the 
equipment, system maintenance and operation, or data collection.
    (4) The public water system must not have been identified as a 
source of a waterborne disease outbreak, or if it has been so 
identified, the system must have been modified sufficiently to prevent 
another such occurrence, as determined by the State.
    (5) The public water system must comply with the maximum contaminant 
level (MCL) for total coliforms in Sec. 141.63 at least 11 months of the 
12 previous months that the system served water to the public, on an 
ongoing basis, unless the State determines that failure to meet this 
requirement was not caused by a deficiency in treatment of the source 
water.
    (6) The public water system must comply with the requirements for 
trihalomethanes in Secs. 141.12 and 141.30 until December 31, 2001. 
After December 31, 2001, the system must comply with the requirements 
for total trihalomethanes, haloacetic acids (five), bromate, chlorite, 
chlorine, chloramines, and chlorine dioxide in subpart L of this part.
    (c) Treatment technique violations. (1) A system that (i) fails to 
meet any one of the criteria in paragraphs (a) and (b) of this section 
and/or which the State

[[Page 436]]

has determined that filtration is required, in writing pursuant to 
Sec. 1412(b)(7)(C)(iii), and (ii) fails to install filtration by the 
date specified in the introductory paragraph of this section is in 
violation of a treatment technique requirement.
    (2) A system that has not installed filtration is in violation of a 
treatment technique requirement if:
    (i) The turbidity level (measured as specified in Sec. 141.74(a)(4) 
and (b)(2)) in a representative sample of the source water immediately 
prior to the first or only point of disinfection application exceeds 5 
NTU; or
    (ii) The system is identified as a source of a waterborne disease 
outbreak.

[54 FR 27527, June 29, 1989, as amended at 63 FR 69516, Dec. 16, 1998; 
66 FR 3776, Jan. 16, 2001]