PENNGROVE, CA., 11/10/26 — On the morning of Oct. 13, a Sonoma Water crew sent a camera into a sewer pipe in Penngrove to check it before the winter rains. The camera showed heavy corrosion and several small to medium holes in the 6-inch cast iron pipe, according to an agency staff report written for a Nov. 17 board meeting.
The pipe is part of an inverted siphon. That’s a stretch of sewer line that dips down to pass under something in its way, such as a creek, and comes back up on the other side.
The crew couldn’t get clear video of the other three siphons, so those were pressure tested Oct. 15. They didn’t pass, the report says.
The damaged sections of pipe are in four places in the Penngrove Sanitation Zone’s sewer system, all near Lichau Creek. Sonoma Water, the county water agency, owns and runs that system. The zone serves the equivalent of 556 single-family homes and sends its wastewater to the city of Petaluma for treatment, according to a 2026 Sonoma Water newsletter about the zone. Much of the system was built in the 1970s, the newsletter says.
No active sewage spill was seen during the inspections, the report says. Staff wrote that the risk comes with rain: Lichau Creek floods in large storms. As the creek rises, water will get into the sewer system through the damaged pipes, and that raises the risk of wastewater overflows, the report says. An earlier staff report, written for an Oct. 27 board meeting, says stormwater could overwhelm the system and that the damage threatens private property.
The National Weather Service forecast for Penngrove calls for rain Friday.
Board suspended bidding for the repair
Sonoma Water’s general manager declared an emergency Oct. 22. On Oct. 27, the agency’s board of directors approved a resolution that suspends competitive bidding for the repair and gives the general manager authority to sign emergency contracts, with a limit of $750,000.
Staff wrote that the usual bidding process takes two to three months, and that contractors already on the agency’s list couldn’t commit to finishing in time.
That earlier report put the cost at an estimated $250,000, based on early inspections.
The agency chose a contractor, Miksis Services Inc., and a repair method called fold-and-form PVC. A plastic liner is pulled through the old pipe while folded, then expanded to fit against the pipe’s walls.
Miksis was scheduled to start cleaning and inspecting the siphons the week of Nov. 2, the Nov. 17 report says. Agency crews have been clearing vegetation so the contractor’s vehicles can reach the site.
Board to vote again Nov. 17
The board is scheduled Nov. 17 to receive a report and decide whether the emergency work should continue. The item is on the consent calendar, the part of the agenda that is usually approved in one vote without discussion. It needs four of five votes.
The general manager will report to the board every 14 days until the repair is made and conditions are safe, the report says.
The Nov. 17 report gives no finish date. It says staff are still assessing the pipes and that the full extent of the repairs is still being determined.
It also says the Penngrove zone’s operations fund for this fiscal year may not be enough to cover the total cost. The agency isn’t asking for more money now. Staff wrote that they will return to the board with a request, if one is needed, once costs are better known.
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