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SUMMARY OF THE REGULATIONS JUN I 9 1989
fitTRFXCE WATER TREATMENT REQUIREMENTS
Background
• Proposal was published in Federal Register on November 3,
1987 (52 FR 42178)
8 Notice of Availability, describing new regulatory options,
was published in the Federal Register on May 6, 1988 (53 FR
16348).
0 Final rule promulgated June, 1989.
Maximum Contaminant Level Goals
Giardia Lamblia 0
Viruses °
Legionella °
Turbidity none
Heterotrophic Plate Count
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Minimum sampling frequencies for fecal or total coliforzn
determinations are:
SYSTEM SIZE (persons) SAMPLES/WEEK
( 501 1
501—3,300 2
3,301—10,000 3
10,001—25.000 4
> 25.000 5
If not already conducted under the above requirements, a
coliforin test must be made each day that the turbidity
exceeds 1 NTU.
Turbidity -levels must be measured every four hours by grab
sample or continuous monitoring. The turbidity level may
not exceed 5 NTU. If the turbidity exceeds 5 NTU, the
system must install filtration unless the State determines
that the event is unusual or unpredictable, and the event
does not occur more than two periods in any one year, or
five times in any consecutive ten years. An “event” is one
or more consecutive days when at least one turbidity -
measurement each day exceeds 5 NTU.
Site Specific Conditions
Disinfection
Disinfection must achieve at least a 99.9 and 99.99 percent
inactivation of Giardia cysts and viruses, respectively.
This must be demonstrated by the system meeting “CT” values
in the rule (“CT” is the product of residual concentration
(mg/i) and contact time (minutes) measured at peak hourly
flow). “C” and “T” must be determined at or prior to the
first customer. The total percent inactivation can be
calculated based on unlimited disinfectant residual
measurements in sequence prior to the first customer.
Failure to meet this requirement on more than one day in a
month is a violation. Filtration is required if a system
has two or more violations in a year, unless the State
determines that at least one of these violations was caused
by circumstances that were unusual and unpredictable. A
third violation in 12 months, regardless of the cause,
triggers filtration.
Disinfection systems must a) have redundant components
including alternate power supply, automatic alarm and
start—up to ensure continuous disinfection of the water
during plant operation or b) have automatic shut—off of
delivery of water to the distribution system whenever the
disinfectant residual is less than 0.2 ing/L, provided that
the State determines that a shut-off would not pose a
potential health risk to the system.
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For systems using chiorarnines if chlorine is added prior to
ammonia, the CT values for achieving 99.9 percent
inactivation of Giardia iambus cysts can also be assumed to
achieve 99.99 percent inactivation of viruses. Systems
using chieramines and adding ammonia prior to chlorine must
demonstrate with on—site studies that they achieve 99.99
percent inactivation of viruses. For systems using
disinfectants ether than chlorine, the system may
demonstrate that other CT values than those specified in the
rule, or other disinfection conditions are provided which
achieve at least 99.9 and 99.99 percent inactivation of
Giardia lamb ia and viruses, respectively.
Disinfectant residuals in the distribution system cannot be
undetectable in more than five percent of the samples, each
month, for any two consecutive months. Samples must be
taken at the same frequency as total coliforms under the
revised coliform rule. A systent.may measure for RPC in lieu
of disinfectant residual. It the HPC measurement is less
than 500 colonies/ml, the site is considered to have a
“detectable” residual f or compliance purposes. Systems in
violation of this requirement must install filtration unless
the State determines that the violation is not caused by a
deficiency of treatment of the source water. For systems
which cannot maintain a residual or practically monitor for
HPC, the State can judge whether adequate disinfection is
provided in the distribution system.
Systems must maintain a disinfectant residual concentration
of at least 0.2 mg/i in the water entering the system,
demonstrated by continuous monitoring. If there is a
failure in the continuous monitoring, the system may
substitute grab sample monitoring every four hours for up to
five days. If the disinfectant residual falls below
0.2 mg/i, the system must notify the State as soon as
possible but no later than the end of the next business day;
notification must include whether or not the residual was
restored within four hours. If the residual is not restored
to at least 0.2 mg/l within four hours, it is a violation
and the system must filter, unless the State determines that
the violation was caused by unusual and unpredictable
circumstances. Systems serving 3300 people or lass can take
daily grab samples in lieu of continuous monitoring.
Minimum grab sampling frequencies are: 1/day ( 501 people;
2/day 501 — 1000 people; 3/day 1001 — 2500 people; 4/day
2501 — 3300 people. It at any time the residual is below
0.2 mg/i, the system must conduct grab sample monitoring
every four hours until the residual is restored.
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Other Conditions
Systems must maintain a watershed control program which will
minimize the potential for contamination by human enteric
viruses and QL! jj cysts. Systems must monitor and
control the activities in the watershed that may have an
adverse impact on water. Systems mu t demonstrate through
ownership or written agreements with landowners in the
watershed that they are able to limit and control all human
activities that may have an adverse impact upon water
quality. The watershed control program and disinfection
treatment must be inspected on—site and approved by the
State annually.
Systems must not have had any waterborne disease outbreaks,
or if they have, such systems must have been modified to
prevent another such occurrence, as determined by the State.
Systems must not be out of compliance with the monthly MCL
for total coliforms for any two months in any consecutive 12
month period, unless the State determines that the
violations are not due to treatment deficiency of the source
water.
Systems serving more than 10.000 people must be in
compliance with I4CL requirements for total trihalomethanes.
Criteria for Filtered Systems
Turbidity Moniçering
Turbidity must be measured every four hours by grab sample
or continuous monitoring. For systems using slow sand
filtration or filtration technologies other than con-
ventional treatment, direct filtration or diatostaceous earth
filtration, the State may reduce the sampling frequency to
once per day. The State may reduce monitoring to one grab
sample per day for all systems serving less than 500 people.
Turbidity Removal
Conventional filtration or direct filtration water must
achieve a turbidity level in the filtered water at all times
less than 5 NTU and not more than 0.5 NTU in more than five
percent of the measurements taken each month. The State may
increase the 0.5 PITU limit up to less than 1 NTU in greater
than or equal to 95% of the measurements, without any
demonstration by the system, if it determines that OVERALL
TREATMENT with disinfection achieves at least 99.9 percent
and 99.99 percent removal/inactivation of Giardia cysts and
viruses, respectively.
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Slow sand filtration must achieve a turbidity level in the
filtered water at all times less than 5 NTU and not more
than 1’ wz’u in more than five percent of the samples taken
each month. The turbiditY limit of 1 NTU may be increased
by the State (but at no time exceed 5 NTU) if it determines
that there is no significant interference with disinfection.
Riatomaceous earth filtration must achieve a turbidity level
in the filtered water at all times less than 5 NTU and of
net more than I !JTU in more than five percent of the
samples taken each month.
Other filtration technolootes may be used if the system
demonstrates to the State that they achieve at least 99.9
and 99.99 percent removal/inactivation of Giardia lamblia
cysts and viruses, respectively, and are approved by the
State. Turbidity limits for these technologies are the same
as those for slow sand filtration, including the allowance
of increasing the turbidity limit of 1 NTU up to 5 NTU, but
at no time exceeding 5 NTU upon approval by the State.
Disinfection Requirements
Disinfection with filtration must achieve at least 99.9 and
99.99 percent removal/inactivation of Giardia cysts and
viruses, respectively. The States define the level of
disinfection required, depending on technology and source
water quality. Guidance on the use of CT values to make
these determinations is available in the Guidance Manual .
Recommended levels of inactivation are based on expected
occurrence levels of Giardia cysts in the source water and
the filtration technology in place. Disinfection
requirements for point of entry to the distribution system
and within the distribution system are the same as for
unfiltered systems.
Analytical Requirements
Except for ozone, testing and sampling must be in accordance
with Standard Methods , 16th edition, or methods approved by EPA
for total celiforms , t ecal coliferm, turbidity, disinfectant
residuals, temperature, and pH. Residual disinfectant
concentrations for ozone must be measured by the Indigo Method
or automated methods which are calibrated in reference to the
results obtained by the Indigo Method.
Reporting
All parameters required in the rule must be reported monthly to
the State. Unfiltered water systems must also report annually
on their watershed control program and on-site inspections.
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Compliance
Surface Wa.ter Systems
Unfilt•red systems must meet monitoring requirements
beginning 18 months following promulgation, unless the
State has determined that filtration is required.
Unfiltered systems must meet the criteria to avoid
filtration beginning 30 months following promulgation,
unless the State has determined that filtration is
required, or they are in violation of a treatment
technique requirement. Unfiltered systems must install
filtration within 18 months following the failure to meet
any one of the criteria to avoid filtration, or within 48
months following promulgation, whichever is later, or
they are in violation.
Filtered systems must meet monitoring and performance
requirements beginning 48 months following promulgation.
The interim turbidity monitoring and MCL requirements
will remain in effect for unfiltered systems until 30
months following promulgation, and for filtered systems
until 48 months following promulgation. For systems
which prior to 30 months following promulgation the State
determines must filter, the interim turbidity
requirements will remain in effect until 48 months
following promulgation, or until filtration is installed.
whichever is later.
Ground Water Systems Under Direct Influence of Surface Water
All systems using ground water under direct influence of
surface water must meet the treatment requirements under
the SWTR. States must determine which community and
non—community ground water systems are under direct
influence of surface water within 5 years and 10 years,
respectively, following promulgation. Unfiltered systems
under the direct influence of surface water must begin
monitoring within 6 months following the determination of
direct influence unless the State has determined that
filtration is required. Systems under direct influence
of surface water must begin meeting the criteria to avoid
filtration 18 months after the determination of direct
influence, unless the State has determined that
filtration is required. Unfiltered systems under direct
influence of surface water must install filtration within
18 months following the failure to meet any of the
criteria to avoid filtration.
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Variances
Vari ices are not applicable.
a ons
Exemptions are allowed for the requirement to filter.
Systems using surface water must disinfect (i.e., rib
exemptions). Exemptions are allowed for the level of
disinfection required.
TOTAL COLIFORMS
Background
o Proposal was published in the Federal 2j er on
November 3, 1987 (52 FR 42224).
o Additional regulatory options were published in the Federal
Register on May 6, 1988 (53 FR 16340).
o Final rule promulgated June, 1989.
Effective date : All public water systems must meet the revised
final coliform MCL and monitoring requirements 18 months after
promulgation of the regulations. Current rule remains in force
until the effective date of the revised rule.
Maximum contaminant level goal : zero
Maximum contaminant level :
• Compliance is based on presence/absence of total
coliforms in sample, rather than on an estimate of
coliform density.
* MCL for systems analyzing at least 40 samples/month: no
more than 5.0 percent of the monthly samples may be total
colif orm—pos it iv.
o MCL for systems analyzing less than 40 samples/month: no
more than 1 sample/month may be total celiform—positive.
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Monitoring recuirements for total coliforzns
• Eac i public water system must sample acco7 fing to a
written sample siting plan. Plans are subj. ect to State
review and revision. The State must esta l 3,zh a process
which ensures the adequacy of the sample siting plan for
each system.
• Monthly monitoring requirements are based oii population
served (see Table 11).
• A system must collect a set of repeat sam s for each
total coljjorm—positive routine sample (sbe, able 12) and
have it analyzed for total coliforms. At ast one
repeat sample must be from the same tap as he original
sample; ether repeat samples must be colle jed from
within five service connections both upstrW and
downstream of the original sample. The ey ea must
collect all repeat samples within 24 hours . f being
notified of the original result, except whVe the State
waives this requirement on a case—be-case basis.
o If total coliforms are detected in any repó t sample, the
system must collect another set of repeat jnples. as
before, unless the MCL has been violated a the system
has notified the State (in which case the ! ate may
reduce or eliminate the repeat sampling re uirement for
the remainder of the month).
• If a system which collects fewer than five i outine
samples/month detects total coliforms in êny. routine or
repeat sample (and the sample is not inval 4ated by the
State), it must collect a set of five rout3fr samples the
next month the system provides water to th 3 public.
except that the State may waive this requirytent if (1)
it performs a site visit to evaluate the co2 ta1ninat1on
problem, or (2) it has determined why the sample was
total coliform—positive and (a) explains th s conclusion
in writing, (b) obtains the signature of t)j supervisor
of the State official who draws this concTh ion, (c)
makes the documentation available to EPA anc the public,
and (d) requires the system to collect at-t,aat one
sample under certain circumstances describid in the rule.
• Unfiltered surface water systems, or systent using
unfiltered ground water under the direct 114,luence oi
surf ace water, must analyze one coliform sam ple each day
the turbidity of the source water exceeds 1 NTU.
o Tables 11 and 12 summarize the routine and epeat sample
monitoring requirements for total celiferms.
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TABLE 11: Total Coliform Sampling Requirements.
ccordifl to Population Served
Mjnjn U! Minimum
number of number of
Population routine samples Population routine samples
served per month 3 served per month
25 to 1,0002 j3 59,001 to 70.000 70
1.001 to 2.500 2 70,001 to 83.000 80
2.501 to 3,300 3 83,001 to 96.000 90
3.301 to 4,100 4 96,001 to 130.000 100
4.101 to 4.900 5 130.001 to 220,000 120
4.901 to 5,800 6 220,001 to 320,000 150
5,801 to 6,700 7 320,001 to 450.000 180
6.701 to 7,600 8 .450,001 to 600,000 210
7.601 to 8,500 9 600,001 to 780,000 240
8.501 to 12,900 10 780.001 to 970,000 270
12.901 to 17.200 15 970,001 to 1,230,000 300
17,201 to 21,500 20 1,230.001 to 1,520.000 330
21,501 to 25.000 25 1.520,001 to 1.850,000 360
25,001 to 33,000 30 1.850,001 to 2,270.000 390
33,001 to 41,000 40 2,270.001 to 3,020,000 420
41,001 to 50.000 50 3,020,001 to 3,960,000 450
50,001 to 59,000 60 3,960,001 or more 480
1 In lieu of the frequency specified in this Table, a non-
community water system using ground water and serving 1.000
persons or fewer may monitor at a lesser frequency specified by
the State until a sanitary survey is conducted and the State re-
views the results. Thereafter, non—community water systems using
ground water and serving 1000 persons or fewer must must monitor
in each calendar quarter during which the system provides water to
the public, unless the State determines that some other frequency
is more appropriate and notifies the system (in writing). Five
years after promulgation, non—community water systems using ground
water and serving 1.000 persons or fewer must monitor at least
once/year.
A non-community water system using surface water, or ground water
under the direct influence of surface water, regardless of the
number of persons served, must monitor at the same frequency as a
like-siz.d community public water system. A non—community water
system using ground water and serving more than 1,000 persons
during any month must monitor at the same frequency as a like—
sized community water system, except that the State may reduce the
monitoring frequency for any month the system serves 1,000 persons
or fewer.
2 Includes public water systems which have at least 15 service
connections, but serve fewer than 25 persons.
For a community water system serving 25-1,000 persons, the State
may reduce this sampling frequency, if a sanitary survey conducted
in the last five years indicates that the water system is supplied
solely by a protected ground—water source and is free of sanitary
defects. However, in no case may the State reduce the sampling
frequency to less than once/quarter.
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TABI 4 E 12: Monitoring and Repeat Sample Frequency
Alter a Total Coliform—Positive Routine Sample
no. routine no. repeat no. routine
samples/month samples 1 samples next month 2
1/mo or fewer 4 5/mo
2/mo 3 5/mo
3/mo 3 5/mo
4/mo 3 5/mo
5/mo or greater 3 Table 11
Number of repeat samples in the same month for each total
coliform—positive routine sample.
2 Except where State has invalidated the original routine
sample, or where State substitutes an on—site evaluation of
the problem, or where the State waives the requirement on a
case—by—case basis.
Invalidation of total coliform-positive samples
o All total coliforin—positive samples count in compliance
calculations, except for those samples which are invalidated
by the State. Invalidated samples do not count toward the
minimum monitoring frequency.
° A State may invalidate a sample only if: (1) the analytical
laboratory acknowledges that improper sample analysis caused
the positive result; (2) the system determines that the
contamination is a domestic or other non—distribution system
plumbing problem on the basis that any repeat sample taken at
the same tap as the original total coliform-positive sample
is total coliform—positive, but all repeat samples at nearby
sampling locations are total coliform-negative; or (3) the
State has substantial grounds to believe that a total
coliferm—positive result is due to some circumstance or
condition not related to the quality of drinking water in the
distribution system, if (a) this judgment is explained in
writing, (b) the document is signed by the supervisor of the
State official who draws this conclusion, and (a) the
documentation is made available to EPA and the public.
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Variances and exemptionS : none allowed
Sanitary surveYs :
0 Periodic sanitary surveys are required for all systems
collecting fewer than 5 samples/month, according to the
schedule in Table 13:
TABLE 13: Sanitary SurveY Preauencv for Public Water
Systems Collectinc Fewer Than Five Samples/Month
Initial Survey Frequency of
System Tv e ComBleted b Sub.eauent Surveys
Community water 5 years after promulgation every 5 years
system
Non-community water 10 years after promulgation every 5 yearst
system
t For a non-community water system which uses protected and
disinfected ground water, the sanitary survey may be repeated
every ten years instead of every five years.
Fecal coliiorms/E. coli; heterotro hic bacteria (RPC )
• If any routine or repeat sample is total coliform—positive.
the system must analyze that total coliform-positive culture
to determine if fecal coliforms are present. The system may
test for . celi in lieu of fecal coliforms. If fecal
coliforms or E. coli are detected, the system must notify
the State before the end of same business day, or, if
detected after the close of business for the State. by the
end of the next business day.
• If any repeat sample is fecal coliform- or . coli—positive,
or if a fecal coliform- or E. coli—positive original sample
is followed by a total coliform-positive repeat sample, and
the original total coliform-positive sample is not
invalidated, the system is in violation of the MCL for total
coliforms. This is an acute violation of the NCL for total
coliforms.
o The State has the discretion to allow a water system on a
case—by—case basis, to forgo fecal coliforzn or E. coli
testing on total coliform—positive samples, if the system
treats every total coliform-positive sample as if it
contained fecal celjforms, i.e., the system complies with
all sections of the rule which apply when a sample is fecal
coliform—positive.
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o State invalidation of the routine total coliform—positive
sample invalid ates lubsequent fecal coliform or .
coli—positive results on the same sample.
o Heterotrophic bacteria can interfere with total coijforin
analysis. Therefore, if the total calif arm sample
produces: (1) a turbid culture in the absence of gas
production using the I(ultiple Tube Fermentation U TF)
Technique; (2) a turbid culture in the absence of an acid
reaction using the Presence—Absence (P—k) Colif arm Test; or
(3) confluent growth or a colony number that is “too
numerous to count” using the Membrane Filter (HF) Technique.
the sample is invalid (unless total coliforms are detected.
in which case, the sample is valid). The system must
collect another sample within 24 hours of being notified of
the result from the same location as the original sample and
have it analyzed for total coliforms. In such cases. EPA
recommends using media less prone to interference from
hateretrophic bacteria for analyzing the replacement sample.
Analytical methodoloav
o Total calif arm analyses are to be conducted using the
10-tube MTF Technique, the MF Technique, the P-A Calif arm
Test, or the Minimal Media ONPG-MUG Test (Autoanalysis
C . . .lilert System). The system may also use the 5—tube MTF
Technique (20-mi sample portions) or a single culture bottle
containing the MTF medium, as long as a 100—mi water sample
is used in the analysis.
o A 100—mi standard sample volume must be used in analyzing
f or total calif arms, regardless of the analytical method
used.
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