Manteca has sent the City of Lathrop a $6 million bill for wastewater treatment dating back to 2016. Either which way, paying Manteca going forward and/or addressing previous years when the money wasn’t paid Manteca apparently because Lathrop was never billed for its contractual obligations, could place upward pressure on existing Lathrop sewer rates. They also have their own wastewater treatment facility in addition to capacity within the Manteca plant. Lathrop has 14.7 percent of the original plant capacity of the Manteca treatment plant built in the 1980s on West Yosemite Avenue. The original plant was paid for by a federal program that provides regional sewer plant funds to upgrade treatment facilities nationwide.