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EF/ ICR Logo Treated Water Levels of Total Trihalomethanes (TTHM) for
City of Spokane


Water System Total Trihalomethanes Report
REMINDER: Data Purpose: The ICR data were collected as part of a national research project to support development of national drinking water standards. They should NOT be used to determine local water systems compliance with drinking water standards, nor should they be used to make personal judgements about individual health risks.

Units: Sample measurements are taken in micrograms per Liter (ug/L) and are regulated in milligrams per Liter (mg/L). A microgram per Liter is equivalent to one contaminant part per billion (ppb). A ppb can be thought of as one grain of salt in a swimming pool. Data for Total Trihalomethanes, haloacetic acids 5, and bromate are presented in ppb. 1 mg/L = 1000 ug/L, or 0.080 mg/L = 80 ug/L = 80 ppb, which happens to be the TTHM standard in the Stage 1 DBP Rule.

Calculation in Regulations is Different: Comparisons with compliance calculations based on the existing Total Trihalomethanes standard in CFR Part 141.30 may not be warranted since the standard is based on an annual average of public water system quarterly averages and not on treatment plant results as shown here. Also the results here are based on different types of samples.

Results of Zero: A result of zero may indicate that a sample was analyzed, but that the result was less than the lowest value that the analytical method can reliably report.


Treated Water Levels of TTHM for Groundwate r Treatment

Water Type Quarter Avg(tthm) (ppb) Min(tthm) (ppb) Max(tthm) (ppb)
Ground Water JUL 1997 - SEP 1997 .3 0 1.2
Ground Water OCT 1997 - DEC 1997 1.1 0 4.5
Ground Water JAN 1998 - MAR 1998 1.1 0 2.8
Ground Water APR 1998 - JUN 1998 .9 0 3.5
Ground Water JUL 1998 - SEP 1998 0 0 0
Not Reported OCT 1998 - DEC 1998 NO DATA NO DATA NO DATA


How does this utility's treated water compare to treated waters nationally for TTHM? Click on "view report" to see the state and national levels of TTHM.

Quarter State Report National Report
JUL - SEP 1997 view report view report
OCT - DEC 1997 view report view report
JAN - MAR 1998 view report view report
APR - JUN 1998 view report view report
JUL - SEP 1998 view report view report
OCT - DEC 1998 view report view report


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