The Environmental Protection Agency oversees the Safe Drinking Water Act. This is one of the primary pieces of legislation that outlines the water quality rules community water systems are required to follow. A portion of this act requires an annual Consumer Confidence Report (CCR) to be provided to all customers. A CCR is an annual water quality report that includes information on water sources, levels of detected contaminants, and the water system's compliance with the drinking water rules. When these reports are prepared, they are presenting information from the previous year. For example, the versions that were mailed out last week by Marana Water includes the data from 2015. These must be delivered to customers by July 1st each year.
In previous years, Marana Water has published the CCR data in the newspaper, but now each customer is mailed a copy of the CCR for their water system each year. The documents can also be viewed on the water quality webpage for this year, and for many previous years.
There is a wide variety of content within the CCRs. Details about the wells used to provide water to the system, any violations of the drinking water rules in the past year, the safety concerns of certain elements that may be found in the water, a terrific glossary of water quality related terms, and sample results are areas covered in the CCR.
When reviewing the results chart, be sure to notice if the measurement is in parts per million (ppm) or parts per billion (ppb). Parts per million, also called milligrams per liter (mg/L) can be compared to one minute in two years, or a single penny in $10,000. If you multiply ppm by 1,000 you will get parts per billion. PPB is the equivalent of one minute in 2,000 years or a single penny in $10,000,000! Identifying the difference in these units can help to understand how much of a compound actually was detected in the water sample.
Some of the inorganic compounds tested for are arsenic, fluoride, and nitrates. Inorganic contaminants can be naturally occurring, or a result of run off from activities near by like mining, farming, or wastewater processing. Most of the minimal detected levels are likely due to erosion of natural deposits or run off from the sources mentioned above. Nitrate levels may rise quickly for short periods of time due to rainfall or agricultural activity. Fluoride, can be naturally occurring, and is sometimes added to water to help promote strong teeth. It is monitored because too much fluoride can, in fact, damage teeth. Marana Water does not add any fluoride to our systems. The Airport system is classified as a "non-transient, non-community water system" due to the number and type of customers using water in this system. This is why there is no test for fluoride below. A new rule was put in place in 2002 regarding arsenic. In high levels (50 ppb or more) arsenic is a carcinogen, so this new rule brought the MCL to 10 ppb to address any potential long term effects it may cause. As shown in the excerpt below, none of the systems approached the Maximum Contaminant Level (MCL) for these compounds. The MCL is the highest level allowed in drinking water. There were no violations in 2015 in any of Marana Water's water systems in regard to nitrates, arsenic, or fluoride.
The CCR compiles water quality tests done throughout the year including total coliform tests and chlorine residuals, which you can read about here. There are close to 3,000 tests done annually by only four operators. These dedicated water professionals work all year to ensure the quality of the drinking water to our customers is safe.