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EPA issues emergency orders to 4 mobile home parks near Thermal due to high levels of arsenic in drinking water

The U.S. Environmental Protection Agency (EPA) issued emergency orders to four mobile home parks located on tribal land near Thermal after high levels of arsenic were found in the drinking water.

The mobile home parks -- Arellano Mobile Home Park, Castro Ranch, Gonzalez Mobile Home Park, and Sandoval Mobile Home Park -- are all located on the Torres Martinez Desert Cahuilla Indians’Reservation in California. 

"These emergency orders support EPA’s larger effort in the Eastern Coachella Valley to ensure all drinking water systems comply with SDWA and provide safe drinking water,” said Martha Guzman, EPA’s Regional Administrator for the Pacific Southwest. “Mobile home park owners and all levels of government must protect the health of residents and comply with federal law.”

The EPA inspected and sampled the four separate water systems in Nov. 2021, according to the agency. The EPA found naturally occurring arsenic in the systems' current source of drinking water. Arsenic is a known carcinogen and drinking high levels over many years can increase the chance of lung, bladder, and skin cancers, as well as heart disease, diabetes, and neurological damage. 

The regulatory Maximum Contaminant Level (MCL) for arsenic in drinking water is 10 parts per billion (ppb). Based on the EPA's sample results, all the systems are currently serving water that exceeds the arsenic MCL:

  • Arellano Mobile Home Park: The system serves approximately 26 residents and has arsenic levels ranging from 14 ppb to 16 ppb. 
  • Castro Ranch: The system serves approximately 40 residents and has arsenic levels ranging from 18 ppb to 19 ppb. 
  • Gonzalez Mobile Home Park: The system serves approximately 40 residents and has arsenic levels ranging from 28 ppb to 29 ppb.
  • Sandoval Mobile Home Park: The water system serves approximately 37 residents and has arsenic levels ranging from 15 ppb to 17 ppb.

According to the EPA, none of the water systems were previously registered with the agency. The systems will now be required to comply with SDWA regulations.

The order requires the park owners to comply with federal drinking water safety requirements and to identify and correct problems with their drinking water systems that present a danger to residents.

Under the terms of EPA’s emergency orders, the owners of Arellano Mobile Home Park, Castro Ranch, Gonzalez Mobile Home Park, and Sandoval Mobile Home Park are required to:

  • Provide at least one gallon of drinking water per person per day at no cost for every individual served by the system;
  • Submit and implement an EPA-approved compliance plan to reduce arsenic below the MCL; and
  • Properly monitor the systems’ water and report findings to EPA.

EPA will continue to oversee the systems’ efforts to follow SDWA requirements and may levy civil penalties if the park owners fail to meet the compliance provisions in the emergency orders.

The Torres Martinez Desert Cahuilla Indians have no direct control or ownership of the water systems. EPA works closely with the Tribe and has consulted their leadership about the violations.

Congressman Raul Ruiz issued a statement on the EPA's announcement:

“Water is life and access to it is a common good and human right. It is outrageous that children in our communities are drinking contaminated water with arsenic that affects their development and ability to learn

Following the events at Oasis Mobile Home Park, I suspected that this is a widespread issue. That is why I called for an EPA investigation to assess the magnitude of contaminated drinking water in our region

We need a comprehensive plan with CVWD and state, federal, and county resources to put an end to these environmental injustices once and for all.”

Since 2019, the EPA has issued emergency orders at least 8 East Valley mobile home parks. All water systems inspected had high levels of arsenic and all are located on Torres Martinez Desert Cahuilla land.

It all started in late 2019 at the Oasis Mobile Home Park. In 2019 and 2020, the EPA conducted multiple samplings of water supplies at the Oasis Mobile Park and issued emergency declarations because of exposure concerns.

Check Out: Rep Ruiz says BIA knew of about unsafe living condition at Oasis Mobile Home Park for more than 13 years

The state is now working to move the residents of Oasis Mobile Home Park to another location. The mobile home park has between 1,000 and 2,000 residents, most of them field workers residing in about 350 mobile homes.

In Dec. 2021, the EPA issued additional emergency orders at Mora Mobile Home Park, Valladares Mobile Home Park and Toledo Mobile Home Park 

The EPA alleges that Mora's water has 52-63 ppb, Valladares' 77-82 ppb and Toledo's water has 63-65 ppb of arsenic. The maximum amount of arsenic allowed is 10 ppb.

In addition, the EPA found the Indian Village Mobile Home Park on Torres-Martinez land to be violating a 2020 order and issued a $3,021 fine for not employing a certified drinking water operator.

For more information on EPA's drinking water program, visit:

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Jesus Reyes


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