DISINFECTANT MONITORING PLAN FOR

___________________________

_________________________________________

_____________, ________, ____________

PWSID #: ______________

Counties Served: ______________

Contact Person: __________________________

Telephone #: _________________________________

System Type: _____________________________

Population Served: _____________________

Source Water Type: _________________________________

Disinfectant: ______________

Treatment Plant Description: ____________________________________________________________________________________________________________________________________________________________________________________________

Distribution System Description: _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

MONITORING PLAN FOR DISINFECTANTS, DISINFECTION BY-PRODUCTS AND DISINFECTION BY-PRODUCT PRECURSORS

To meet the Maximum Residual Disinfectant Level (MRDL) for Chlorine, the system:

Measures chlorine ___________ daily at the entry point with _________________________ to monitor the finished water. The free chlorine reading is recorded each day on the MOR.

Measures free chlorine in the distribution system each month at the same time as total coliforms are sampled and the results are recorded.

Locations of sampling sites can be found in our Bacteriological Sampling Plan, with monthly distribution samples recorded on the MOR and MRDL is calculated based on an annual average of monthly averages.

The system will calculate compliance with the MCL, MRDL’s and treatment techniques by:

Measuring the free chlorine residual for each routine distribution and, if applicable, each repeat total coliform sample taken during the month.

Determine the monthly average free chlorine disinfectant residual by dividing the sum of the monthly distribution chlorine residuals by the total number of distribution chlorine residual samples taken.

After determining monthly chlorine residual averages for 12 months, divide the sum of the monthly chlorine residual averages by 12 to determine the running annual average. This gives the annual average MRDL value.

If the MRDL value is 4.0 mg/l or less the system is in compliance.

This process must be repeated every quarter after the first year by dropping the first three months of chlorine residual averages and using the past three months. MRDL compliance will be determined every quarter on the past 12 monthly chlorine residual averages.

To meet compliance for disinfection byproducts (DBP), the following locations have been identified as collection sites for TTHMs and HAA5s:

______________________________________ Maximum Residence

This sample represents the makeup of the ___________________________, being identified as having the maximum residence time. The maximum residence time site was selected by evaluation of historical data for free chlorine residual and by estimating the time of travel in the distribution main and tanks.

Other locations are not required, but the following average residence sites may be used if needed:

____________________________________

____________________________________

____________________________________

The system will calculate compliance for TTHMs and HAA5s by:

For TTHMs and HAA5s, the system is required to, and will monitor, once per year. The samples will be collected beginning August 2004.

We will take the sum of the total values of the annual TTHM compliance samples and divide by the number of compliance samples to determine the average results for the year.

For annual compliance calculation, add the quarterly results and divide by the number of quarterly TTHM samples.

The same procedure will be used for calculating HAA5 compliance.

If the annual arithmetic TTHM average is 0.080 mg/l or less, and the HAA5 average is 0.060 mg/l or less, the system is in compliance.

TOC monitoring is not required for ___________________________ .

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THM Monitoring Plan template

Tony Wyatt

2004-01-29

TAUD