Crozet Water Testing Results

What are the results from last year's testing?

The table in this report shows which compounds were detected in your drinking water. The following are a few terms which need to be defined to understand the table.

  • Maximum Contaminant Level Goal (MCLG): the level of a contaminant in drinking water below which there is no known or expected health risk. MCLGs allow for a margin of safety.
  • Maximum Contaminant Level (MCL): the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as possible using the best available treatment technology.
  • Maximum Residual Disinfectant Level (MRDL): the highest level of a disinfectant allowed in drinking water. The addition of a disinfectant is necessary for control of microbial contaminants.
  • Maximum Residual Disinfectant Level Goal (MRDLG): the level of a drinking water disinfectant below which there is no known or expected risk to health.
  • ppb: parts per billion, or micrograms per liter (ug/l). One part substance per billion parts of solution.
  • ppm: parts per million, or milligrams per liter (mg/l). One part substance per million parts of solution.
  • pCi/l: picocuries per liter. This is a measure of radioactivity.
  • Nephelometric Turbidity Unit (NTU): a measure of the clarity of water. Turbidity in excess of 5 NTU is just noticeable to the average person.
  • Action Level (AL): the concentration of a contaminant, which, if exceeded, triggers treatment or other actions by the water provider. This term is typically limited to discussions of lead and copper concentrations.
  • n/a: not applicable.
  • < : less than.
Crozet Test Results

Click on the chart to enlarge.

  • 1Unit of measure for total and fecal coliform bacteria is the presence or absence of bacteria in a 100 ml sample.

  • 2Of the 144 samples collected in 2017, four (4) samples indicated the presence of total coliform bacteria. One (1) of these four samples indicated the presence of fecal coliform bacteria. However, all repeat samples were absent for total and fecal coliform bacteria.

  • 3Fecal coliform MCL: A routine sample and a repeat sample are total coliform positive, and at least one is also fecal coliform positive.

  • 4The MCL for turbidity is for no single measurement to exceed 1 NTU, and for 95% of all measurements to be below 0.3 NTU.

  • 5 Sampled in 2017.

  • 6EPA considers 50 pCi/l to be the level of concern for beta particles.

  • 7Sampled in August, 2016 from select, high-risk residences.

  • 8The value reported is the 90th percentile of all data (20 samples) collected.

  • 9The fluoride feed system was offline when the inorganics sample used for reporting was collected in July, 2015.

  • 10The value reported is the highest quarterly, system-wide average.

  • 11TTHM and HAA results are averaged over four quarters at each sampling location to determine compliance with the MCL. Range of detections are from 2017, but “Result” includes 2016 and 2017.

What do all these numbers mean?

Of great importance, this information shows that your drinking water met and exceeded all regulatory requirements during 2017. We are fortunate to have a reliable source for your drinking water needs, anda well operated treatment facility. Additional information is provided on the left that will give you more detail on each potentially harmful contaminant or compound detected in your drinking water.


Cryptosporidium is a microbial pathogen found in surface waters throughout the U.S. Ingestion of Cryptosporidium may cause cryptosporidiosis, an abdominal infection characterized by nausea, diarrhea, and abdominal cramps. Cryptosporidium may be spread through means other than drinking water. Most healthy individuals can overcome the disease within a few weeks. However, immuno-comprised people are at risk of developing a potentially life threatening illness. In 2009, the RWSA conducted an EPA-mandated, one year study of Cryptosporidium in source water for the Crozet WTP. The monitoring did not reveal the presence of any Cryptosporidium in the Beaver Creek Reservoir. Although filtration removes the pathogen, the most commonly used filtration methods cannot guarantee 100% removal. The RWSA makes every effort to optimize the filtration process at all of the WTPs to ensure the greatest degree of Cryptosporidium removal. Based on the results of this study, our water source has been placed in the lowest risk category for exposure to Cryptosporidium.