Why are treatment plants dumping sewage into the Bay?
12.5 million gallons entered our watershed in 2008 alone
The amount of raw sewage illegally entering San Francisco Bay - from sewage treatment plants! - is staggering. In 2008, over 13 million gallons of sewage escaped from treatment plants in 2,048 separate spills, the vast majority of which ended up in the streams and lakes of the Bay watershed. The recently publicized spill of 720,000 gallons of sewage by the Sausalito-Marin City Sanitary District, and Richmond's less-publicized spill of a million gallons of raw sewage just a week later, are only the tip of the iceberg.
A major contributor to the problem is stormwater entering sewers through cracked and leaky sewage pipes. When this happens on a large scale, it can quickly overwhelm the sewage-treatment facilities and exceed the capacity of both storage and treatment ponds. Ultimately, the partially treated or raw sewage mixed with copious amounts of stormwater enters the Bay or its tributaries. Mechanical and human failures in the treatment facilities account for additional illegal discharges.
(The situation is different in San Francisco, which has its own set of problems. San Francisco has a "combined" sewer system, where wastewater and stormwater intentionally go into the same system. All other Bay Area sewage systems are designed to exclude stormwater.)
According to the Regional Board's database the top five chronic offenders in 2008 (by gallons illegally discharged into the Bay) are:
- 1. Hillsborough, 2.96 million gallons in 53 reports;
- 2. Richmond, 2.36 million gallons in 32 reports;
- 3. San Bruno, 1.58 million gallons in 50 reports;
- 4. Sonoma County Water Agency, 871,230 gallons in 27 reports;
- 5. Novato Sanitary District, 419,475 gallons in 26 reports.
Why is this happening in the environmentally savvy Bay Area?
Hillsborough has plenty of tax revenue to fix the problems; why hasn't it done so? Apparently Richmond has been non-compliant for many, many years, and perhaps Sonoma County and Novato have outgrown their sewage capacity due to rapid development.
It's not just a matter of malfunctioning treatment facilities: inadequate capacity has become a widespread problem as developed areas increase in density or sprawl outward, and areas with older infrastructure and aging, cracked sewer pipes continue to suck in extra rain and groundwater. Many sewage districts face a trade-off between increasing capacity versus fixing and replacing pipes to keep stormwater out. The East Bay Municipal Utility District, in cooperation with all the municipalities in its area, for example, carried out a huge multi-year project to detect and repair sources of infiltration. Complicating the issue is the problem that the "lateral" pipes connecting homes to the main sewer are owned by the individual property owners. Privately owned pipes create a legal and enforcement tangle for the local sewer and oversight agencies, and no one seems yet to have developed a workable solution.
Perhaps the largest and most politically thorny problem is the reluctance to step up and pay for the necessary upgrades - by the elected boards that administer sewage facilities, homeowners, and so on. Just who should finally take environmental and financial responsibility for 13 million gallons of partially or untreated sewage dumped into our Bay waters, if not the users of the systems?
The Bay Chapter Water Committee will begin examining the issue of illegal sewage discharges to Bay waters at its Mon., May 18, meeting, 7 - 8:30 pm at the Chapter Office, 2530 San Pablo Ave. in Berkeley, (510)848-0800.
For more information contact Water Committee chair Matt Morrison at (925)846-3835 by email to mattmorrisonus -at- gmail.com or Marin Group chair Elena Belsky at (415)488-9341 or elena_scmg -at- comcast.net
To find out more about sewage problems in your area, try the California Integrated Water Quality System (CIWQS) Database. It's a highly searchable tool for regulatory, compliance, and enforcement information; by site, county, date, city, and other parameters. It was the source for all the numbers in this article.