How Does Water Get Polluted?
The water you use everyday doesn't go away. Stormwater runs off streets and driveways and eventually ends up in creeks, the Napa River and in the bay without any treatment. Wastewater from your house goes down toilets, sinks, and shower drains and makes its way through an extensive collection and treatment process. While the treatment plant effectively removes organic material, it is not designed to remove chemicals and metals. So, when toxic chemicals get dumped or rinsed down household drains, they pass through the system untreated and end up in the creeks, the Napa River, the Bay system, and even the Pacific Ocean where they may threaten sensitive aquatic life.

How does Napa Sanitation District Prevent Water Pollution?
Controlling toxics at their source is the most effective way of keeping pollutants out of the local water environment. Since our treatment plant is not designed to remove chemicals and metals, the goal of our Pollution Prevention and Source Control Program is to monitor the wastewater discharged at various points of our collection (underground pipeline) system and ensure that businesses and industries are complying with discharge requirements. Our Source Control Program began in the mid 1970's in response to the Clean Water Act and continues to improve strategies to reduce pollutants discharged to the sanitary sewer.

Since there are over 25,000 households in Napa, enforcement is very difficult, if not impossible. NSD prefers to take a different approach, with Public Education and Outreach. NSD believes that the more people that understand the hazards of toxic discharges to the sewer, the less likely they are to pollute. NSD has developed educational programs for students, the general public, and businesses with the goal of informing them about how to reduce or even eliminate toxic discharges.

Check out this site for more pollution prevention information

Mercury-What are the issues?
Since the Napa Sanitation District's Wastewater Treatment Plant processes only remove some of the mercury in wastewater, much of the toxic metal finds its way back into our environment.
Many of California's surface water bodies contain too much mercury. The State Water Resource Control Board has listed 860,000 acres of estuaries, lakes and reservoirs and 303 miles of rivers and creeks as mercury impaired including the San Francisco Bay.
Fish consumption warnings due to elevated mercury levels exists for San Francisco Bay and several lakes. Bioaccumulation of mercury is the primary concern-mercury concentrations are higher in species that are higher in the food web.

What Can We Do?
Mercury Thermometer Exchange:
People are most commonly exposed to mercury by way of broken fever thermometers. A typical old-fashioned thermometer contains about a half gram of mercury. Oral thermometers are often used and stored in the bathroom, and when they break, the mercury is frequently washed down the drain. In fact, the half-gram of mercury in a thermometer is enough to pollute 5 million gallons of water! Because mercury can contaminate the air, soil and water when they are crushed in landfills, old-fashioned thermometers also should not be thrown in the trash. To reduce the risk of hazardous waste contamination, the Napa Sanitation District will replace your old thermometer with a new digital one that doesn’t contain mercury?. At No Cost To You!