How to Read a Water Quality Report

In celebration of August as National Water Quality Month, we thought you’d appreciate a little primer on reading your city or water agency’s water quality report, also known as a consumer confidence report or CCR.

What type of information is found in your report? Sources of your drinking water, a brief summary of the risk of contamination, regulated contaminants found, and potential health risks of contaminants detected that exceed an Environmental Protection Agency (EPA) health standard. In addition, the CCR provides education information on nitrate, arsenic or lead and statements on cryptosporidium, which are all contaminants that might be of concern.

The CCR features a chart and one of the first columns will list chemical names such as bromate or chloride. In another column, you will see the MCL. This stands for maximum contaminant level—the highest level of that contaminant found during sampling. Another column will feature the MCLG, the maximum contaminant level goal. If the value in the water source columns is below the MCLG, there’s no known health risk. The range column shows if contaminant levels detected were high or low. The MCL violation column shows if a contaminant that is in your drinking water is above allowed EPA levels. Your water quality report will, additionally, outline any violations, what they are and when it happened.

You’ll also see strange words like turbidity, which is a measure of cloudiness of the water and an indication of particles in the water. Low turbidity is an indication of good water quality and effective filtration of contaminants in drinking water.

Every year, the Orange County Water District (OCWD: the District) Water Quality department collects close to 20,000 samples from more than 1,500 locations throughout the Orange County Groundwater Basin. OCWD’s Philip L. Anthony Water Quality Laboratory conducts 400,000 separate analyses of the water samples. The results for samples collected at drinking water sites are provided to the 19 OCWD member agencies in north and central Orange County to be included in their annual water quality report (CCR) for consumers.

The Lab, by the way, can detect contaminants down to parts per trillion—that is like one drop in 26 Olympic-size pools. In addition, it is one of only four public agency labs in the nation certified to provide full chemical analyses using Unregulated Contaminant Monitoring Rule 4 (UCMR4) for five Environmental Protection Agency methods. These include 28 trace contaminants and constituents of emerging concern. The gathered information is then used to support future regulatory decision-making and supports the administrator’s determination of whether (or not) to regulate a contaminant listed in the UCMR program.

The District’s Lab is also the first public agency laboratory in California to achieve state certification to analyze for polyfluoroalkyl substances (PFAS), which are a group of thousands of synthetic chemicals that have been in use since the 1940s to make carpets, clothing, fabrics for furniture, paper packaging for food, and other materials (e.g., non-stick cookware). Although they are now banned in the U.S., they have found their way into our air, soil and drinking water.

OCWD has invested more than $1 million in monitoring equipment to test for PFAS and constituents of emerging concern. These are the result of OCWD’s commitment to exceptional water quality for its member agencies and the 2.5 million people they serve.