Santa Rosa may be zeroing in on the cause of the contamination in the water supply of the devastated Fountaingrove neighborhood, but there are also troubling signs that the problem may extend beyond the immediate advisory area.
Since Jan. 24, when the city last released detailed test results, the city has found 58 additional instances of benzene in the drinking water in the Fountaingrove area.
The vast majority came from the 184-acre area north and south of Fountain Ggrove Parkway around Fir Ridge Drive, an area once home to 350 families.
Only 13 homes remain following the October wildfires.
Residents of the area have been under a strict advisory for months to not drink or boil the water while the city tries to find the source of the contamination and fix the problem, something that could cost upwards of $20 million if the area’s water system needs replacement.
The maximum containment level (or MLC) for benzene in drinking water in the state is 1 part per billion.
The first batch contained four test results showing benzene levels over 500 parts per billion, one of which was as high as 918 parts per billion.
But seven of those results were from outside the existing advisory area.
Six of those results were under 10 ppb, while the seventh was something of an outlier at 240 parts per billion, Horenstein said.
All the seven locations are located at burned home sites.