2019-073 Drinking Water MonitoringDate: April 12, 2019 Report No. 2019-073
INFORMAL STAFF REPORT
TO MAYOR AND CITY COUNCIL
SUBJECT:
Provide information about August 2018 drinking water monitoring violation requiring public
notification.
DISCUSSION:
The City received a violation notification from the Texas Commission on Environmental Quality
(TCEQ) regarding the Revised Total Coliform Rule (RTCR) for August 2018. Per Title 40 of
the Code of Federal Regulations (CFR) §141.860(c), Denton did not collect every routine sample
according to the City’s Sample Siting Plan (SSP) in 2018. The City is required to collect and test
a minimum of 120 drinking water samples for total coliform every month. However, 119 of the
required 120 coliform monthly drinking water samples were collected for August 2018. The
sampling violation was not a violation of public health standards, instead it was a clerical
oversight. Since August 2018, staff have collected every required coliform sample and Denton is
no longer in violation.
A series of events led to the oversight in sampling in August 2018. During the last week of the
sampling cycle water was shut off at one of the sampling stations scheduled for completing the
120 sample batch. This location was skipped for sampling, however the recently-hired
technician failed to substitute the shut off sampling location with another sampling site. The
microbiologist responsible for receiving and testing for the samples was out of the office and the
deficiency in the number of samples collected was discovered after the reporting cutoff date.
Staff’s opinion is that there was a very low probability of the public health being compromised
by this violation. The testing history of the shut off sampling location is provided below:
On August 8 drinking water was sampled and passed bacteriological test.
On August 28 water was shut off and unable to sample.
On September 13 drinking water was sampled and passed bacteriological test.
Corrective actions have been implemented since the violation occurring. The sampling protocol
was revised to reflect the following: before the end of every month two different lab personnel
would verify that all required coliform monitoring samples have been collected; training for
technicians to emphasize that monthly TCEQ RTCR compliance requirements require the
minimum collection of 120 samples; and starting in October 2018 there are to be 123 samples
collected monthly.
As a part of the TCEQ violation notification, Denton must provide public notice of this violation
to the persons served by Denton’s drinking water system before August 31, 2019. The public
notice is scheduled to be mailed out in conjunction with the consumer confidence repot (CCR) to
all water customers and the notice would also be published in the local newspaper. The mail out
is scheduled to start on the first week of May.
Date: April 12, 2019 Report No. 2019-073
Please contact Assistant Director of Environmental Services, Deborah Viera (contact information
below) for additional information.
STAFF CONTACT:
Deborah Viera, Assistant Director of Environmental Services
940.349.7162
Deborah.Viera@cityofdenton.com