Water Quality Notifications

Some samples of raw (untreated) water in the Contra Loma Reservoir and Contra Costa Canal contained cryptosporidium; however, cryptosporidium was not detected in your treated drinking water. Cryptosporidium is a microbial pathogen found in surface water throughout the United States. It is spread to water through human and animal activity. Current test methods do not identify whether cryptosporidium organisms are dead or if they are capable of causing disease.

Although filtration removes cryptosporidium, the most commonly used filtration methods cannot guarantee 100% removal. To address cryptosporidium, the State of California has implemented a Cryptosporidium Action Plan, and your water provider is treating your drinking water to the requirements of this plan. In addition, the City of Martinez, Diablo Water District and Contra Costa Water District are treating water with ozone, which is potentially the most effective disinfectant currently available.

Swallowing cryptosporidium may cause cryptosporidiosis, an abdominal infection characterized by nausea, diarrhea and abdominal cramps. Most healthy individuals can overcome this disease within a few weeks. However, immunocompromised people are at greater risk of developing life-threatening illness. We encourage immunocompromised people to talk to their doctors about precautions they can take to avoid infection. Cryptosporidium must be swallowed to cause disease, and it may be spread through means other than drinking water.

Methyl-tertiary Butyl Ether

CCWD checks untreated water at numerous locations in its reservoirs and canal for Methyl-tertiary Butyl Ether (MTBE) 4 times a year. MTBE is an oxygenate additive to gasoline used to meet federal and state clean-air emissions standards. In October 1999, a sample taken from the Los Vaqueros Reservoir indicated an MTBE level of 18 parts per billion (ug/L). It appears this result was caused by sample contamination. All other samples taken in 1999, as well as a follow-up sample taken in March 2000, showed no detectable level of MTBE. Samples can be contaminated in a number of ways, including improper collection, contaminated sample bottles or lab error. To protect water quality at Los Vaqueros, recreational gasoline boats are not allowed on the reservoir because they can be a source of MTBE.