The water system serves the Desert View Picnic Ground, the volunteer activity center known as the Red Tailed Roost, the Sierra Club Lodge, Camp Ole Fire Station and the Visitor Information Center with public restrooms, along with the Laguna and Burnt Rancheria campgrounds, according to the DEH.
The agency said the drinking water system tested positive for E.Coli and total coliform bacteria.
It's the second time in about three months that such an order was issued for the system, which does not serve the area's restaurants or lodges, which receive water from the Stuart Water Company.
Stuart also serves most other private businesses and residences. The order also doesn't affect the Mount Laguna Improvement Association system, operated by the association of private cabin owners who own Forest Service cabins in the area.
The presence of E.Coli bacteria indicates that the water may be contaminated with human or animal wastes, according to the county. Contamination could result in diarrhea, cramps, nausea, headaches or other symptoms, and present a more serious risk for young children, some elderly and people with compromised immune systems.
Total coliform bacteria can come from soils and other sources in the environment and can indicate a problem with the water supply system.
The county said the Boil Water Order was issued to ensure all water that is used is free from contamination.
The order will remain in effect until laboratory results confirm the absence of bacteria in the water supply.