By Kathryn Reed

Precautionary signs are up at Fallen Leaf Lake after 10 gallons of raw sewage entered the lake early Friday morning.

“The signs will be removed once the water quality at the spill site is at the same baseline level as water found at other points around the lake,” South Tahoe Public Utility District lab director Dan Arce told Lake Tahoe News.

Fallen Leaf Mutual Water Co., which supplies the drinking water to the South Shore enclave, did not return calls. Lahontan Regional Water Quality Control Board, which oversees water issues, also could not be reached.

At 4:40am June 29, the district’s lab took water samples at the point of entry, 60 feet into the lake, and 60 feet east and west along the shore of the spill. All four samples resulted in no detectable levels of ammonia.

STPUD confirmed a sewer blockage at 369 Fallen Leaf Lake Road after getting a call from a customer at 7:44pm June 28. District personnel found a sewer blockage on the private sewer lateral with some spilled sewage pooling around the private manhole.

The plan was to work until the block was cleared in order to minimize damage. At midnight, the blockage was cleared and the backed up sewage gushed downhill through the sewer lateral. The rupture overloaded the district’s vactor truck, which was at the downhill manhole to suction out the overflow. This is when the 10 gallons reached the lake.

“Our crew realized that once the line was unplugged, a freight train of sewage would flow downhill and surcharge the district’s manhole at the bottom of the hill. This particular manhole sits only 10 feet from the edge of Fallen Leaf Lake,” district General Manager Richard Solbrig said in a statement. “The crew’s foresight to station the district’s vactor truck at the downhill manhole, resulted in 99 percent of the sewage overflow to be captured.”

The district predicts if a private plumber had unblocked the clog, that the manhole cover would have been blown off and 1,800 gallons of sewage would have inundated the lake.

“When a sewage blockage is cleared, a rake is put into a downstream manhole to try and catch whatever was causing the blockage and prevent further issues. In this case, a chunk of asphalt the size of a golf ball was removed,” Shelly Thomsen with STPUD told LTN. “There may have been more that got past the rake. We don’t know how the asphalt got into the private sewer lateral. It could have been vandalism, as most manhole covers aren’t locked.”