In the midst of an ongoing debate over how the San Geronimo Valley should fix its wastewater woes, residents met Monday night to learn whether a particular septic system technology could work for their homes. AdvanTex Treatment Systems represents a potential on-site septic solution for the valley, where a high water table prevents effluent from percolating fully through residential leach fields—causing foul odors and fecal seepage during the rainy winter season. Pollution from the sludge combined with sediment runoff also threatens to contaminate creeks in a watershed where salmon populations spawn. Valley residents remain split over whether individual homeowners should upgrade their septic systems or the community should chip in to construct a large sewage treatment facility at the golf course. Bill Beck, a sales manager for Orenco, the manufacturer of AdvanTex, gave a presentation to around 35 people on two different systems, and fielded questions from the audience ranging from odors to installation details to how the systems should be cleaned. Liza Crosse, an aide for Marin County Supervisor Steve Kinsey, conjectured that AdvanTex systems would cost residents as much as $60,000, though Mr. Beck said he could see no reason for the systems to cost more than $30,000, or less if a group of homeowners tied to a larger-sized filter unit that would handle greater capacity. Some worried that the groundwater table in the Woodacre Flats is too high to give the two-foot clearance space between the discharge pipes and the water table. Mr. Beck noted that such homes would have to install raised mounds to give the systems more room. Others wondered whether such onsite systems would encourage increased residential development in the valley. Mr. Beck said AdvanTex systems could handle up to four bedrooms in a house, and possibly six bedrooms with a high-end system. Ms. Crosse urged the San Geronimo Valley Planning Group, which hosted the informational meeting on AdvanTex, to hold similar meetings with representatives from other septic system companies.