What happened?
The Authority exceeded the maximum contaminant level (MCL)
for Total Trihalomethanes (TTHM) at one of the eight monitoring locations in
the service area. The results at this sample location was 80.9. parts per
billion (ppb).
What are TTHMs?
TTHMs are a
group of four chemicals that are formed during the water treatment process
when chlorine reacts with organic materials such as leaves, plants and soil
in the untreated water. Chlorine is the most common disinfectant used to
eliminate disease causing pathogens (i.e. bacteria and viruses). A rise in
TTHMs can result from increased chlorination during the treatment process,
high organics in source water, drought conditions, or limited water
circulation within the pipeline system.
How often does the Authority sample?
SMCMUA is required to sample each of the eight sites every
quarter.
Has this happened before?
Up until the third and fourth quarters of 2018, the Authority has not exceeded the MCL at any of the
eight locations since the start of this monitoring program in April 2012.
What are the health risks of TTHM?
In accordance with the USEPA, people who drink water
containing trihalomethanes in excess of the MCL over many years may
experience problems with their liver, kidneys, or central nervous system,
and may have an increased risk of getting cancer.
Is the water safe to drink, bathe, wash in?
USEPA states that there is nothing you need to do. You
do not need to boil your water or take other corrective actions.
How did the Authority notify customers?
SMCMUA issued a direct mail
public notice, published
information on its website and updated local public officials.
What is the Authority doing to correct the problem?
SMCMUA's
Operations Division
installed
a flushing station at the location of the violation so that it can reduce
the water age which has and will
continue to result in
a reduction in the TTHM.
SMCMUA's
Engineering Division is also evaluating options to loop the system so that
it will not have to flush to reduce the water age.
SMCMUA's Water Quality
Division changed the sourcewater
provided to the affected sample site from a purchased surface water supply
to an Authority owned groundwater supply.
