Civil Engineering Reference
In-Depth Information
TABLE 1-7. MCL, Health Effects, and Monitoring Requirements for Microbiological Contaminants
Name of Contaminant
Maximum Contaminant Level (MCL)
Health Effects of Contaminant
Monitoring Requirements
Total Coliform rule (TCR)
Total Coliforms
Fecal Coliforms
E. coli
Less than 40 samples / month; no more than 1
positive for total coliforms. If 40 samples or
more / month, no more than 5% positive.
MCLG
The presence of fecal coliforms or
E.
coli
may indicate potential contami-
nation that can cause diarrhea,
cramps, nausea, headaches, or other
symptoms.
For both surface waters and groundwaters, the total
number and location of samples is based upon the
population served and a system-specific sampling plan
(see regulations).
0 for total coliform, fecal coli-
form and
E. coli.
Every sample containing total coliforms must
be analyzed for fecal coliforms.
Surface Water Treatment rule
Turbidity
0.5 NTU in 95% of samples of filtered water,
5 NTU max
Treatment technique (MCLG
None. Interferes with disinfection.
Turbidity: Grab samples at least every four hours or con-
tinuous monitoring.
Giardia
Enteric Viruses
0)
Giardiasis.
Gastrointestinal and other viral infec-
tions.
Legionnaires' disease.
Gastrointestinal Infections.
Treatment technique (MCLG
0)
Continuous chlorine residual required for systems
3,300.
One to four grab samples per day are allowed for sys-
tems
Legionella
Heterotrophic Plate Count
(HPC)
Treatment technique (MCLG
0)
Treatment technique (MCLG
none)
3,300.
Interim Enhanced Surface
Water Treatment rule
Turbidity
Conventional and direct filtration systems must measure
combined filter effluent turbidity at least every four
hours and continuously monitor turbidity of each indi-
vidual filter. PWSs that do not have four quarters ac-
ceptable TTHM and HAA5 data must conduct
monitoring for four quarters (must be completed by
February 2000). If annual average for TTHM
0.3 NTU in 95% of samples of filtered water,
1 NTU max
Treatment technique (MCLG
None. Interferes with disinfection.
Cryptosporidium
0)
Cryptosporidiosis.
0.064
mg / L or HAA5
0.048 mg / L and less than three
years acceptable operational data exist, a PWS must
monitor disinfectant residual, temperature, pH (chlo-
rine only), and peak hourly flow on a daily basis for
its Disinfection Profile (must begin by February 2000
and continue for one year).
