SLO investigating 25,000-gallon raw sewage spill that forced evacuation, beach closure
The city of San Luis Obispo is still investigating the cause of a large spill that released 25,000 gallons raw sewage spill this week, reviewing video footage captured underground of the main plumbing line in question in the Orcutt Road area.
The spill, which first came up out of the ground Sunday night, later flowed around and partly into a residential building at 1110 Orcutt Road before finding its way into two local creeks, said Jeremy Gearhart, SLO’s wastewater collection supervisor.
Gearhart said the city has relocated at least one tenant to a hotel, and “possibly two,” because untreated sewage entered the inside of at least one of the homes at the Orcutt complex.
“Other tenants in the building are OK,” Gearhart said. “There was no impact to their homes, just minor spills that came up into bath tubs, but they didn’t spill over and the tubs have since been disinfected. After the blockage was dislodged, we cleaned up around the complex and area. It has all been pressure-washed and hydrocleaned.”
About 525 sewer connections exist upstream from the spill, generating the flow that led to the spill, Gearhart said.
Not a water leak as first thought
The incident was initially reported as a water leak about 10 p.m. Sunday that ran for about 12 hours until it was identified as a raw sewage spill.
Gearhart said crews responded by dislodging the unknown obstruction using a high-pressure hydrocleaner, which unplugged the system.
City officials initially assessed the spill at 3,500 gallons, but the spill investigation was still ongoing, later tallying the seepage at around 25,000 gallons.
“City staff was still in the process of cleaning up the site, assisting with property owners whose homes were impacted, and totaling the spill volume,” Gearhart said.
The hydrocleaner contains a camera on the hose nozzle that captured some of the work being done underground. Crews are examining the footage, which is expected to show evidence of what bottled up the piping. The hydrocleaner was successful in “pulling (the object) back downstream.”
“In the past, we’ve had roots and offset joints (where pipe joints no longer properly connect) that have caused some problems,” Gearhart said. “But we haven’t determined the cause yet.”
SLO looking at other sewer lines
Gearhart said the city also is reviewing video of a series of main sewer lines in a quest to make sure there’s “nothing else to lead to another blockage.”
The spill funneled wastewater into a storm drain system that entered Alrita-Carla Creek, a tributary of San Luis Obispo Creek, which flows to Avila Beach.
City officials say it’s best to stay out of the creeks, and typically closures last for at least 72 hours after a spill. Signs have been posted in English and Spanish, including at the northern end of Avila Beach, which has been closed as well.
Gearhart said he hasn’t seen a full 10-inch main line blocking in his nine years with the city. The main line piping runs along the major corridors of the city.
In the past, 6-inch pipe blockages have occurred, the size of piping that typically branch out and run underground on residential streets.
Gearhart said the city has fully cleaned up the spill on city streets and at the affected property, and will cooperate with any follow-up assessment by the Regional Water Quality Control Board, which has the authority to penalize the city if it determines any violations occurred.
How SLO monitors private sewer laterals
SLO has a current sewer later program in which private property owners, under various circumstances, could be required to replace sewer laterals at a cost of up to $10,000. The city is offering a $2,000 rebate for those who replace their infrastructure.
Private lateral piping extends from homes to the city streets and are the responsibility of the property owner.
Some of the events that could trigger an inspection, and a potential update, include:
▪ Private sewer overflow
▪ Building permit applications for a bathroom or kitchen
▪ Building permit applications for non-residential structures with plumbing fixtures
▪ Subdivisions
▪ Changes in ownership of property
Unlike public sewer lines, these private sewer laterals “are not routinely inspected, maintained, or repaired/replaced on an interval to ensure they are in good condition,” SLO officials said in a staff report in August.
This story was originally published March 10, 2020 at 1:26 PM.
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