Some Gilbert water customers received notice that one area of the town’s water system violated drinking water standards due to higher levels of a chemical compound, trihalomethane, reported in routine monitoring.
Town officials say this is not an emergency and Gilbert’s water is safe.
Here are five things you need to know about the water quality notice, according to a town news release:
- Your water is safe to drink.
Total Trihalomethanes (TTHMs) pose an increased risk of cancer to individuals who consume water containing high levels of the chemical over their entire lifetime and to certain vulnerable populations.
- What are TTHMs?
TTHMs, or total trihalomethanes are a group of four organic compounds formed in your water when naturally occurring organic material reacts with chlorine used for microbial disinfection.
- This notice applies to ‘Zone 1’ in Gilbert.
The area of Gilbert west of SRP’s eastern canal is isolated from the rest of the water system. In this zone, one of the six compliance locations exceeded the maximum contaminant level for TTHMs.
- The maximum contaminant level is based on a yearly average.
April’s sample result, when averaged with the three other samples taken over the past year, brought the average level of TTHMs above the 80 parts-per-billion maximum contaminant level at one of Gilbert’s testing sites.
- How did this violation occur?
In October there was a mechanical failure of Gilbert’s TTHM removal equipment in a nearby water storage reservoir. This failure, and the resulting levels of TTHMs, did not in itself trigger a violation, but increased the average for that location.
The source water at the North Water Treatment Plant, which serves the area of Zone 1, experienced incoming levels of organic material over 25 percent higher than the seasonal average for previous years.
While the treatment plant was adjusted and optimized to remove more of the incoming organics, this resulted in higher TTHM levels in April which caused the violation.
For more information contact Gilbert’s Water Quality Division at [email protected].