The 11 water systems were ordered to reduce the arsenic levels by treating the water or replacing or rehabilitating their water wells to meet federal arsenic level standards by 2010. Systems that fail to comply face penalties of up to $32,500 per day for each violation.
The standard as of Jan. 23, 2006 is 10 parts per billion, the equivalent of a few drops of ink in Olympic-size swimming pool. The level set in the 1970s was 55 parts per billion, the EPA said.
A water system is considered out of compliance if arsenic readings are above 10 parts per billion for four consecutive quarters. The EPA said levels above 15 or 20 parts per billion are of concern, particularly to children, pregnant women and those with compromised immune systems.
Arsenic is a naturally occurring mineral found throughout the United States. It is a known carcinogen, and ingesting high levels over many years can increase the chance of lung, bladder and skin cancers as well as heart disease, diabetes and neurological damage, according to the EPA. It inhibits the body's ability to fight off cancer and other diseases.
The Sonoma County public water systems identified as being out of compliance are Groskopf Warehouse and Logistics in Sonoma; Rancho de Sonoma Mobile Home Park in Sonoma; Lancelot Mobile Home Park in Santa Rosa; the public water system operated by Niels Chew at 21600 Eighth St. in Sonoma and J. Vineyards & Winery in Healdsburg.
The five water systems serve between 30 and 200 people, and the levels of arsenic in their water ranged between 18 and 50 parts per billion, the EPA said.
The 11 water systems are required to submit a written compliance plan that describes how they will return their drinking water systems to compliance and the management controls that will be put in place.
Everett Pringle, coordinator of the EPA's Region 9 Drinking Water Enforcement Office, said the water systems singled out are expected to be fully compliant by 2010. He said they will be eligible for financial assistance to make any necessary infrastructure improvements.
The EPA said it will also assess whether the public water systems need more time to comply with the arsenic standards as 2010 nears.
The arsenic standard applies to 54,000 community water systems in the United States. A community water system is one that serves at least 15 locations or 25 residents year-round, including most cities, towns, apartments and mobile home parks with their own water supplies.
The EPA estimates 5 percent, or 3,000 community water systems serving 11 million people, will have to take corrective action to lower the current levels of arsenic in their drinking water.
EPA officials said the 11 water systems are the first in the state to be cited for non-compliance and that 20 or 30 more will receive enforcement notices.