Study finds expanded valley wastewater system best bet


A study on expanding the proposed Woodacre Flats wastewater project released this month concluded that the best option would serve roughly 370 homes and businesses in Woodacre and San Geronimo. 

The study builds on a previous but more limited examination of options to address leaky septic systems; that study only foresaw recycling wastewater from 210 homes, a project that would have cost roughly $9 million to build.

The new preferred alternative, which would cost $14 million in capital costs, will now be used as a baseline for an environmental impact report. A public scoping period for that report, which will also assess other options, launched last week and lasts until May 1. 

A meeting last week convened by the county to review the new study drew over 80 people to Lagunitas School, where some residents were skeptical about both the project’s complexity and how many people would want to participate in it.

But the meeting also affirmed the problem of human waste impacting the watershed. 

County planner Lorene Jackson presented the results of the county’s microbial source tracking tests of San Geronimo and Woodacre Creeks. The tests, taken in December and February at three sites, sometimes detected markers for dogs, ruminants and horses, but markers for human waste were the most commonly detected markers during the wet winter. 

More testing will take place through the spring.

The San Geronimo Valley Planning Group is conducting its own separate testing of more of the valley using a different method, known as the Phylochip.

The idea to shift homeowners in the flats of Woodacre from individual septic systems to a community system is a decade old. People who formed the Woodacre and San Geronimo Flats Wastewater Group said failing septics in areas poorly suited for them were releasing wastewater, making it stink after rains and likely contaminating creeks. 

But many people, along with the planning group, long critiqued the project on many counts, including its potential growth impacts and the perceived dangers of piping wastewater around the valley.

The first speaker at last week’s meeting referenced that community division. Rich Lohman, part of the wastewater group, quoted two lines from the Persian poet Rumi: “Out beyond ideas of wrongdoing and right doing, there is a field. I’ll meet you there.” He recited the verse twice, and told the audience that the community needed to find that field.

The expansion study builds on a 2011 study that considered serving the 150 homes in the Woodacre flats with either a leach field or a wastewater recycling system that would irrigate the San Geronimo Golf Course in the dry season. The study also nominally considered a no-project alternative (a legal requirement) as well as a program that would work to update only failing septic systems. 

The new study—supported by a $75,000 grant from a State Water Resources Control Board fund that supports water recycling—is much more expansive, with seven options. It still includes a no-project alternative, a program updating existing systems, and an option to just serve the Woodacre flats with a community leach field, though that alternative would serve 176 parcels, up from the previous 150 parcels.

There are also four new or revamped options for recycling wastewater, though they all share one major purpose: to send wastewater through a series of underground gravity and pressure lines to a 10,000-square-foot treatment plant. There, waste would be filtered and disinfected with ultraviolet radiation and then piped to one or two lined ponds at the San Geronimo Golf Course. Those ponds would need to be large enough to accommodate a 100-year rainfall event, per state regulations. A buried tank on the golf course would be able to handle 24 hours of flow if the system malfunctioned, and the entire system would be constantly monitored. 

If the project comes to fruition, either a community services district or the Board of Supervisors would oversee it. Both options would entail hiring a firm to manage operations.

One of the recycled wastewater options would treat 210 homes in Woodacre. Another, called the “partial service” alternative, would recycle wastewater from 270 parcels in Woodacre and San Geronimo—or roughly three quarters of the homes in the flats of those villages. A further expansion would serve virtually all the flats, or 360 parcels.

An even larger possibility, the report says, would have the Lagunitas School District and the French Ranch subdivision decommission their leach fields and hook into the project. Theoretically, even some homes in Forest Knolls could participate. That alternative would serve the equivalent of 420 homes.

The report ranked these alternatives on multiple factors, including cost, regulatory compliance, reliability, environmental impacts, energy use, water conservation and land impacts. The water-recycling alternatives scored more poorly on energy use, because building the treatment facility and running it would take much more energy than a simple community leach field. 

But the water recycling options better with respect to environmental impacts because of the recycled water they would provide, as well as on regulatory compliance, since the wastewater would be filtered and disinfected.

The alternative serving 360 parcels ranked the highest, although the option including the school district and French Ranch ranked just one point lower. But the report says these two are not necessarily mutually exclusive, as the latter “could be undertaken in a subsequent phase as an expansion.”

These projects are not cheap. The preferred alternative, which would produce 16.28 million gallons of recycled water annually, would cost $14.3 million—or $39,788 per parcel—in capital costs. Operations and maintenance is estimated to cost $1,004 per parcel per year. And that was one of the cheapest options. 

A project that served only the Woodacre flats would cost $45,542 per parcel in capital costs and $1,356 per year in operations and maintenance. A Woodacre community leach field, without water recycling, would be less expensive, at $37,670 per parcel in capital costs and $885 a year in operations and maintenance. 

Those costs do not include what it would cost a homeowner to run pipes from a property to the road, which Norm Hantzsche, of Questa Engineering, which conducted the studies, estimated would cost between $1,500 to $3,000 per parcel.

Those costs could come down with grant funding, but some people are skeptical that enough homeowners in the project are interested. “There is very lukewarm support for this, in my opinion,” said Jean Berensmeier, a longtime valley resident on the planning group’s steering committee.

Brian Staley, the group’s chair, asked how the county would “identify the most troubled systems” to ensure that they hook up. Among many other concerns, the group has wondered whether people with failing septics would be prioritized over others.

But the project would actually require people to opt out, not in. Ms. Jackson said that if homeowners in the project area vote to create an assessment district, they must either hook up or prove to the county that their septic systems are in working order. Liza Crosse, a former aide to Supervisors Steve Kinsey and Dennis Rodoni, chimed in: barring mandatory home inspections, the project area had been defined by homes closest to the creek, which are assumed to be the most troublesome.

Homeowners in the project area would vote on whether to assess themselves to pay for the project. 

One man from Woodacre said it seemed unfair that only people in the project area would vote on a district to fund the project. “It seems like this is going to affect the whole valley,” he said.

Ms. Jackson responded that while only people in the project area would vote on the district, the Board of Supervisors would vote on ratifying the environmental impact report, a process that would include opportunity for public comment.

Valley resident Amos Klausner also critiqued the project during the meeting, listing recent wastewater spills, the possible proximity of pipes to ephemeral streams at the golf course and the potential for offensive odors, among other things. (The wastewater project would include a biofilter odor system.)

Growth is also a major concern. The environmental impact report will consider ways to address concerns about how the project could facilitate growth by eliminating septic systems—a major limitation to development, and in particular to adding bedrooms to homes, since they can only handle a limited amount of effluent.

While a growth-limiting mechanism has not been outlined, presenters referenced the community wastewater project in Marshall, where each home was allotted 500 extra square feet of development, though not in the form of bedrooms. 

And though the project is intended to serve existing homes, the environmental report may analyze serving undeveloped lots for affordable housing.

“The project is aimed at developed properties, not vacant properties, but the county also has an important role in providing affordable housing,” Ms. Jackson said.

A draft of the environmental analysis is expected in the fall, when another period of public comment will be held. Those comments will be addressed in the final report, expected in the spring or summer of 2018, which the Board of Supervisors will vote on certifying. 

A public scoping session will be held at 6 p.m. on Tuesday, April 18 in the Lagunitas School Multipurpose Room. For a copy of the study, visit Written comments should be sent to or Rachel Reid, Environmental Planning Manager, 3501 Civic Center Drive, Suite 308, San Rafael, CA 94903.