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TTHM Frequently Asked Questions
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The District exceeded the maximum contaminant level or MCL based on the average of Total Trihalothames (TTHM) samples taken over one year.
Water sample results from April 14, 2016 to February 24, 2017 showed the annual average of Total Trihalomethanes levels at three locations of 92 parts per billion (ppb), 87 ppb and 84 ppb.
What are the health risks of TTHMs?
Some people who drink water containing TTHMs in excess of the MCL for many years could experience liver or kidney problems, nervous system effects, and an increased risk of cancer
Is the water safe to drink, bathe, wash in?
Yes, the water provided by East Valley Water District is safe for all uses. There is no need to take additional actions that would be required in a water emergency such as a boil order. If an emergency such as that existed, East Valley Water District along with the State Water Resources Control Board would immediately notify the community.
If you have other health issues concerning the consumption of this water, you may wish to consult your medical doctor. East Valley Water District has notified Loma Linda University Medical Center, Beaver Medical Group, St. Bernardine Medical Center Dignity Health, and Kaiser Permanente. If your medical doctor does not belong to one of these providers, please give them a copy of this notification.
Health and safety is the District's top priority.
What were the water quality violations?
The District exceeded the maximum contaminant level for TTMS at three sampling sites. Because compliance is measured based on an average, it may take multiple samples to return to compliance.
The District has increased water quality sampling, and current results are below the MCL.
How did the District notify customers?
The District sent out a mail piece to account holders and tenants throughout the service area, in addition to posting information on the District's website, information included at a regularly scheduled board meeting, posting notices at the District office, and held a community meeting on May 10, 2017 at 7:00pm.
The regulatory requirement only required the District to provide a basic notification to the community. The District has exceeded the minimum notification requirements in order to answer any questions or concerns that customers may have.
Is there someone I can talk to about this issue?
For more information contact Mike Hurst at the District's Water Quality Department at (909) 806-4222.
What are you doing to fix the problem?
There are short term and long term solutions.
- We are working with the State Water Resources Control Board– Division of Drinking Water to evaluate the water supply and researching options to correct the problem. These options may include treating the water to remove TTHM or adjusting the District's water supply.
- Because compliance is measured based on an average, the District anticipates returning to compliance by late 2017.
- However, current water samples show that the water provided today meets state and federal standards.
- We anticipate having permanent solutions to this problem by April 2019, which include several infrastructure projects. In the meantime, staff is making a number of adjustments to continue water quality for our community, for example:
- Increased water quality sampling
- Increasing system water circulation to prevent stagnation
- Adjusting the water supply used in response to the water quality sampling results
- Evaluating new treatment processes
- Strategic fire hydrant flushing
What are the long-term solutions?
District staff is currently developing a long-term action plan. In order to address this issue, a number of different factors need to be considered. Some of the potential options include an additional treatment process at the surface water treatment plant, installation of a new pipeline to enhance water circulation to prevent stagnation.
Why did this happen?
The District uses three different sources of water, including groundwater, Santa Ana River Water, and State Project Water from northern California. Santa Ana River Water and State Project water are called surface water sources, meaning they come from a running river or stream. These sources of supply are heavily impacted by the environment, including storm patterns, seasonal changes, drought and changes in temperatures. During the warm times of the year, the District experiences the highest demand for water from customers and historically uses a high amount of both surface and groundwater.
During the fall of 2016, there were historically high levels of TTHMs, resulting in an increased quarterly result. Minor fluctuations in TTHMs are normal, which is why the regulation is based on an average, rather than a single sample. In March 2017, the Santa Ana River water had unusually high levels of organics through a combination of the droughts and the storage and release of stormwater from behind the Seven Oaks Dam.
Is this going to mean a rate increase on my water bill?
No. This can be resolved using the existing Capital Improvement Project funding to cover the infrastructure projects in the action plan.