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News Releases from Region 09

U.S. EPA issues emergency order to Oasis Mobile Home Park drinking water system

Contact Information: 
Soledad Calvino (

TORRES MARTINEZ, Calif. – The U.S. Environmental Protection Agency (EPA) has ordered the Oasis Mobile Home Park on the Torres Martinez Tribe’s lands in California to provide alternative drinking water, reduce the levels of arsenic in the system’s water and monitor the water for contamination.  

“EPA is committed to ensuring everyone, including the Oasis Park residents, receives water safe to drink,” said EPA Pacific Southwest Regional Administrator Mike Stoker. “We will continue to work with the drinking water system and the tribe to meet this most basic need.”

“The Torres Martinez Desert Cahuilla Indians appreciates the cooperation and assistance of the U.S. Environmental Protection Agency in enforcing the federal Safe Drinking Water Act on the Torres Martinez Indian Reservation,” said Torres Martinez Desert Cahuilla Indians Tribal Council Chairman Thomas Tortez, Jr. "As partners with EPA, we support EPA’s enforcement efforts to protect persons living on the Torres Martinez Indian Reservation at the Oasis Mobile Home Park, a privately-owned business, from high levels of naturally occurring arsenic in the drinking water.”

The Oasis Mobile Home Park Public System serves approximately 1,900 residents using groundwater that has naturally occurring arsenic. The regulatory Maximum Contaminant Level (MCL) for arsenic is 10 parts per billion (ppb) for drinking water. EPA found the system was serving water that violated the MCL in 2019, based on sampling results ranging from 16 ppb to 97 ppb. 

The tribe has no direct control or ownership of the water system and has been consulted about the violations.

The order requires Oasis Mobile Home Park and its owner to: 

  • Provide at least one gallon of drinking water per person per day for every individual served by the system.
  • Increase sampling and reporting of arsenic levels. 
  • Provide a technical review of the arsenic treatment system to analyze the cause of the violations and identify how to correct it. 
  • Develop standard operating procedures to ensure proper operation of the arsenic treatment system.
  • Provide verification that the system has a certified water operator. 

Failure to comply with the EPA’s order could result in penalties levied against the Oasis Mobile Home Park of up to $23,963 per day. 

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