The South Bayside System Authority claims it is still plucking between 20 and 40 pieces of jail clothing from its system monthly, General Manager Dan Child said.
Child said items from the jail have included T-shirts, pants, jumpsuits, pillowcases, boxer shorts, socks, trash bags, plastic ware and sheets.
San Mateo County officials say local jail inmates are flushing fewer clothes down the toilet these days, but a local wastewater agency that has sued the county over the problem disagrees.
The authority, which serves southern San Mateo County, sued the county in January for more than $900,000 to cover the cost of dealing with items flushed by Maguire Correctional Facility inmates.
The problem started in 2004 when the clothing started clogging grinders at the sewage agency's Redwood City pump stations.
"The volume drastically increased," Child said. "There has always been some, but just nowhere near the amount at that time and since that time, and we don't know why."
"We were able to identify that it was coming from the jail because some of what we received said 'San Mateo County Jail' on it," Child said.
After issuing a cease-and-desist order in 2005 demanding the county stop inmates from flushing inappropriate items, Child said the number of trash bags being flushed decreased.
"They were successful at stopping the trash bags," Child said. "However, the clothing has continued to be a problem."
Grinders at the Redwood City pump station had to be removed because they could not handle the volume of non-wastewater items, Child said. Screens that catch the items replaced the grinders but have to be removed and cleaned several times each day, he said.
Deputy County Counsel Portor Goltz said the wastewater agency is putting too much blame on the county.
"What comes down to the pump station is not just from the jail," Goltz said.
He said the county was aggressive in dealing with the flushing problem once it was identified as an issue.