Microsoft Word - WaterChemistry

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Chemical Monitoring.........................

The final federal rules regarding Phase II and V contaminants were promulgated by the U.S. EPA
in 1992 and initial monitoring began in January 1993. This group of contaminants consists of
Inorganic Chemicals (IOC), Volatile Organic Chemicals (VOC) and Synthetic Organic Chemicals
(SOC) and the rule applies to all community and non-transient non-community public water
systems.

The monitoring schedule for these
contaminants is phased in by
water system population size
according to a “standardized
monitoring framework”
established by the U.S. EPA. This
standardized monitoring
framework establishes nine-year
compliance cycles consisting of
three 3-year compliance periods.
The first compliance cycle began
in January 1993 and ended
December 31, 2001, with
subsequent compliance cycles
following the nine-year timeframe.
The three-year compliance period
of each cycle is the standard
monitoring period for the water system.

Turbidity Monitoring
Monitoring for turbidity is applicable to all public water systems using surface water sources or
ground water sources under the direct influence of surface water in whole or part. Check with your
state drinking water section or health department for further instructions.

The maximum contaminant level for turbidity for systems that provide filtration treatment:

1. Conventional or direct filtration: less than or equal to 0.5 NTU in at least 95% of the
   measurements taken each month. Conventional filtration treatment plants should be able to
   achieve a level of 0.1 NTU with proper chemical addition and operation.


2. Slow sand filtration, cartridge and alternative filtration: less than or equal to 1 NTU in at least
   95% of the measurements taken each month. The turbidity levels must not exceed 5 NTU at any
   turbidity measurements must be performed on representative samples of the filtered water every
   four (4) hours that the system serves water to the public.

A water system may substitute continuous turbidity monitoring for grab sample monitoring if it
validates the continuous measurement for accuracy on a regular basis using a protocol approved
by the Health or Drinking Water Agency, such as confirmation by a bench top turbidimeter.

For systems using slow sand filtration, cartridge, or alternative filtration treatment the Health or
Drinking Water Agency may reduce the sampling frequency to once per day if it determines that
less frequent monitoring is sufficient to indicate effective filtration performance.