THE TASK AT HAND
Next year, Central San will proudly celebrate 80 years of dedicated service to our community. As we take a moment to reflect on our history, we remain focused on the task at hand: ensuring our wastewater system is ready to meet the needs of the future.
Every year at our treatment plant, we clean more than 13 billion gallons of wastewater. That's equivalent to 50 Olympic-sized swimming pools every single day. However, parts of our system are reaching the end of their operational lifespan. Currently, we are working on the most transformative upgrades to our plant since the passage of the Clean Water Act in 1972.
At the top of our agenda is an extensive, multi-year rehabilitation of our solids handling facilities, including seismic upgrades and the replacement of aging equipment. These improvements will ensure we can continue reliably processing wastewater solids while complying with strict air quality regulations.
We're also making excellent progress on renovations to our aeration basins, which will enhance seismic reliability, boost efficiency, and extend the lifespan of these critical facilities. As just one measure of the magnitude of this project, this summer we completed two concrete pours, each requiring the coordination of two giant pumps and over 50 trucks of concrete.
Alongside our other upgrades, we are preparing to launch a large-scale demonstration test of Membrane Aerated Biofilm Reactor technology. This cutting-edge treatment method has the potential to help us meet stringent new nitrogen limits at a lower cost than traditional treatment processes. You can read more about this exciting project on page 4.
In short, the task at hand is about much more than concrete and steel: It's about delivering service you can count on while honoring our commitment to environmental stewardship. With your support, we are building a resilient wastewater system that will serve our community for decades to come.
As we prepare to mark Central San's 80th anniversary, I invite you to save the date for our Open House event on June 13, 2026. We look forward to celebrating with you!
Roger S. Bailey General Manager
NEIGHBORHOOD UPGRADES
Central San regularly maintains, repairs, and replaces sewer lines and other parts of our wastewater collection system to ensure trouble-free service for our customers. Our construction projects may cause shortterm inconveniences, but they provide long-term benefits for you and your neighbors. We appreciate your understanding!
Here’s what we’re currently working on: (estimated start/completion dates in parentheses)
39-INCH MAIN TRUNK #1 RENOVATION will install approximately 0.8 miles of 8-inch main sewers, allowing approximately 1.25 miles of 39-inch main sewers to be decommissioned in the Marsh Drive neighborhood of Pacheco. (Current – December 2025)
PUMPING STATION UPGRADES, PHASE 2 will replace/retrofit three pumping stations in Martinez. (Current – December 2025)
PLEASANT HILL, PHASE 3 will replace approximately 1.5 miles of sewers primarily in the Gregory Gardens neighborhood of Pleasant Hill. (Current – January 2026)
BUCHANAN LIFT STATIONS ABANDONMENT AND SEWER PROJECT will replace 1.0 miles of sewers, while also decommissioning two aging pumping stations on John Glenn Drive and sewer mains crossing the Buchanan Field Airport in Concord. (Current – May 2026)
PLEASANT HILL, PHASE 4 will replace approximately 1.8 miles of sewers primarily in the Gregory Gardens neighborhood of Pleasant Hill. (Current – May 2026)
NORTH ORINDA, PHASE 9 will replace approximately 1.9 miles of sewers primarily in Tappan Lane, Brookbank Road, Lombardy Lane, Mariposa Lane, El Dorado Lane, Las Cascadas Road, and Linda Vista, as well as various locations in Orinda, north of Interstate 24. (November 2025 – June 2026)
LAFAYETTE, PHASE 16 will replace approximately 2.1 miles of sewers in the Dolores Drive, Moraga Road, Walnut Lane, Burton Drive, Windsor Drive, Reliez Station Road, and Mosswood Drive neighborhoods of Lafayette. (February – December 2026)
To learn more about these or other construction projects, please contact Senior Community Affairs Representative Chris Carpenter at ccarp@centralsan.org or (925) 229-7200, or visit: centralsan.org/construction
CENTRAL SAN PREPARES FOR GROUNDBREAKING MABR DEMONSTRATION TEST
Central San is preparing to launch a large-scale demonstration test of Membrane Aerated Biofilm Reactor (MABR) technology—the first test of its kind in California. This innovative wastewater treatment technology could help us meet stringent new nitrogen regulations at a lower cost than conventional technologies.
Using traditional treatment processes, Central San would need to build expensive new aeration basins and clarifiers to meet the 40% nitrogen reductions required under the new regulations. In contrast, MABR offers an exciting opportunity to "do more with less" by enhancing treatment within our existing basins.
Our aeration basins provide an oxygen-rich habitat for millions of beneficial microorganisms that break down pollutants in wastewater. To increase nitrogen removal, we need these microorganisms to linger longer in the treatment process. MABR uses gas-permeable, hollow membranes to deliver oxygen directly to a thin layer of microorganisms
NUTRIENTS AND WASTEWATER
Nutrients like nitrogen and phosphorus enter our wastewater from human waste, food waste, soaps, and detergents. Even after wastewater is cleaned to rigorous required standards, some nutrients remain in the water that the Bay Area's wastewater treatment facilities release into San Francisco Bay.
Nutrients are essential for life, but excessive levels can contribute to harmful algae blooms. With climate change, historically "normal" levels of nutrients may now be too much for the Bay's ecosystem.
known as a biofilm. This biofilm provides an ideal environment to support a diverse microbial community that can efficiently remove nitrogen.
Last year, Central San's Optimization Division successfully completed a seven-month MABR pilot test. We found that the technology performed well under varied conditions and showed great promise for helping us achieve the necessary reductions. The pilot project garnered regional and national attention and was honored with the 202425 Dr. Jenkins Research Achievement Award from the California Water Environment Association. We are now working hard to prepare for a large-scale MABR demonstration in one of our four aeration basins. This includes installing structural supports for the MABR equipment, along with big bubble mixers and baffles to optimize hydraulic flow and maximize the effectiveness of the technology. We anticipate launching the demonstration test in 2026. Stay tuned for updates in future issues of Pipeline!
The San Francisco Bay Regional Water Quality Control Board has identified nitrogen as the primary nutrient of concern for the Bay, prompting new regulations requiring all Bay Area wastewater agencies to reduce nitrogen discharges by 40% from 2022 levels by October 2034. Achieving this target will require significant upgrades to treatment facilities across the region, at an estimated price tag of $11-13 billion for Bay Area residents.
BY THE NUMBERS:
MAINTAINING AN AWARD-
WINNING COLLECTION SYSTEM
Before we can clean your wastewater, it must reach our treatment plant safely. Our Collection System Operations (CSO) team is responsible for cleaning, inspecting, and maintaining our pipes and pumping stations to keep wastewater flowing smoothly.
Through their dedication and expertise, we've achieved one of the best reliability records in the state. This past year, more than 99.99999% of flows reached the treatment plant without incident! To cap off a successful year, Central San was honored as the Large Collection System of the Year by the California Water Environment Association.
What does it take to maintain a collection system that sets the standard for excellence? Here's some of what our CSO crews accomplished in 2024:
INSPECTED
133 miles of pipe using closed-circuit TV cameras
CLEANED
748 miles of pipe to remove grease, wipes, roots, and other clog culprits
WE NEED YOUR HELP!
As you can see, we work hard to keep our sewer system in tip-top shape. However, as amazing as our employees are, they cannot be everywhere at once. If you see, smell, or suspect a sewage spill, please call us immediately at (925) 933-0990. We will dispatch a crew to investigate and take appropriate action as quickly as possible.
REMINDER: WIPES CLOG PIPES!
Unlike toilet paper, wipes don't disintegrate easily (if at all) when flushed. They clog pipes in homes, and cause clogs, sewage spills, and equipment malfunctions in our pipes, pumping stations, and treatment plant. Please help keep our system flowing smoothly by disposing of all wipes where they belong: in the trash.
PROVIDED
24/7 on-call emergency response
74 spot repairs and 17,263 work orders
992 vehicle and equipment services, MAINTAINING
100% uptime for our fleet
PROTECT YOUR PIPES THIS HOLIDAY SEASON: KEEP FOG OUT!
The holiday season is all about enjoying time with loved ones—and, of course, indulging in festive foods! Before you dive into your holiday cooking and baking, take a moment to protect your home’s plumbing. Fats, oils, and grease (FOG) might seem harmless when rinsed down the drain, but they can build up in your pipes, causing costly (and messy) sewage blockages and backups.
Follow these simple steps to keep your pipes flowing smoothly this holiday season:
WIPE: Use a paper towel to soak up greasy residue from plates and pans before washing them.
LEARN MORE: Reach out to your local solid waste service provider for additional FOG disposal options and guidelines.
SCRAPE: Dispose of leftover food scraps in the compost bin.
RECYCLE: Bring your used cooking oils and grease to our Household Hazardous Waste Collection Facility. They’ll be recycled into biofuel, helping the planet while keeping your pipes clear!
By following these quick tips, you can enjoy your celebrations worry-free, without the headache of clogged drains or plumbing emergencies.
Wishing you happy (and clog-free) holidays from everyone at Central San!
RESIDENTS: Mon. – Sat., 7 a.m. – 2 p.m.
BUSINESSES: Mon. – Sat., by appointment
REUSE ROOM: Mon. – Sat., 7 a.m. – 1:30 p.m.
RECYCLED WATER FILL STATION: Mon. – Sat., 7 a.m. – 2 p.m. (May close during periods of rain; please call ahead: 925-335-7717) HOLIDAY CLOSURES: Nov. 27–28, Dec. 24 – Jan. 1
THERE’S EVEN MORE TO LOVE ABOUT COMPOSTING
You probably already know about the many benefits of composting, from reducing landfill waste to conserving water, enriching soil, and promoting healthier plants. But did you know composting also offers bonus benefits for our wastewater system?
PROTECTING YOUR PIPES: Common food scraps— like peels, eggshells, coffee grounds, and starchy or fatty leftovers—can contribute to sewer blockages and backups. By keeping these items out of your kitchen sink drain and garbage disposal, you can protect your household plumbing and help keep our sewer system working well.
PROTECTING THE ENVIRONMENT: Food waste is high in nutrients like nitrogen and phosphorus. When nutrients enter our wastewater system, they can eventually reach local waterways, contributing to harmful algae blooms. Composting helps reduce nutrient levels in our wastewater and protects our beautiful Bay. (Read more about how Central San is tackling nutrients on page 4.)
Whether you have a backyard compost system or use the “green bin” provided by your solid waste service provider, your composting efforts make a difference. Thank you!
RESTORING A MARSH &
Take a stroll or paddle through the newly restored Pacheco Marsh and you’ll see native plants thriving, wildlife returning, and a landscape coming back to life. What you may not notice is the pipeline under your feet—a hidden but vital link between Central San’s wastewater system and the environment it helps protect.
Running beneath Pacheco Marsh, our outfall pipeline carries millions of gallons of cleaned water daily from our treatment plant to Suisun Bay. To safeguard this critical piece of infrastructure, Central San worked closely with John Muir Land Trust (JMLT), Contra Costa County Flood Control District, and other partners throughout the design and construction of the marsh restoration project. "This is our only outfall, so it's crucial to protect it," explains Central San Associate Engineer Amanda
PROTECTING A
Cauble. "JMLT and the other partners were great to work with and really listened to our needs."
Central San's engineering, survey, and inspection teams all helped with the project, reviewing plans and providing input to ensure we can access the pipe for maintenance. They also monitored the site during construction, including installing special leveling monuments on the pipe to check for any elevation changes.
"It's been impressive to see these public access, habitat restoration, and flood control improvements become a reality," says Senior Engineer Dan Frost. "The restoration of Pacheco Marsh truly exemplifies the power of partnerships."
Like 90% of the Bay Area's tidal wetlands, Pacheco Marsh suffered significant human impacts in the
A PIPELINE
MEET OUR OUTFALL
"The restoration of Pacheco Marsh truly exemplifies the power of partnerships."
last century, when it was diked, drained, and filled with dredge spoils. Beginning in the early 2000s, the county, JMLT, and other partners worked to acquire the land from private owners and transition management of Lower Walnut Creek from the Army Corps of Engineers back to local control. In 2019, construction began to carve out new tidal channels, and in 2021 the levee was breached to allow water to flow back in.
Beyond providing habitat, the restored marsh will enhance water quality and provide a natural buffer against floods and sea level rise. JMLT has also constructed trails, bridges, a kayak launch, and other facilities to allow visitors to enjoy this special place. Interpretive signs help to highlight the natural and human history of the marsh. If you visit, look for a sign about Central San's outfall!
Every day on average, Central San cleans about 35 million gallons of wastewater. Apart from a portion we recycle, we return most of this water safely to the environment via our outfall. Built in 1958, this 6-foot diameter, reinforced concrete pipe carries cleaned water from our plant north to Suisun Bay. The pipe extends for about 3.5 miles, including a 1,700-foot section under the bay where the water is released through diffusers. A weir structure allows clean water to flow out while preventing bay water from backing up into the pipe.
VISIT PACHECO MARSH
John Muir Land Trust's Pacheco Marsh is located at 2501 Waterfront Road, Martinez, and is open daily from dawn until dusk. Parking gate hours are 9 a.m. – 5 p.m. Find a map and visitor information at: jmlt.org/our-places/pacheco-marsh
POLLUTION PREVENTION & RECYCLED WATER WINNERS
Congratulations to our 2025 Pollution Prevention Award Winners and Recycled Water Champions! Every year, Central San teams up with Sustainable Contra Costa to celebrate those who are helping to keep our community healthy, beautiful, clean, and resilient. This year’s winners were honored at the 17th Annual Leadership in Sustainability Awards Gala in September.
RECYCLED WATER BUSINESS CHAMPION
GARNEY CONSTRUCTION
Various sites within Central San’s service area
Garney Construction is a national leader in water and wastewater construction. Since June 2024, they have used over 106,000 gallons of recycled water for dust control at their construction sites. We thank them for helping to conserve precious drinking water supplies!
RECYCLED WATER CITIZEN CHAMPIONS
LINDA GALLAGHER & MARGE MCCLEAN
Martinez
Linda Gallagher and Marge McClean are customers of Central San's Residential Recycled Water Fill Station. From July 2024 to June 2025, they visited 227 times, collecting 62,425 gallons of recycled water. They use the water to irrigate over two acres of abundant landscaping at their property, which doubles as a spiritual center in Martinez. Thank you, Linda and Marge, for being frequent and dedicated recycled water customers, and for creating a beautiful outdoor space for people to enjoy!
POLLUTION PREVENTION PARTNER
BIKE CONCORD
Concord
Bike Concord helped Central San launch our award-winning Go With the Flow Bike Tour program in 2023 and has been an invaluable partner ever since. They have aided us in outreach to the broader cycling community, provided bike guides for our rides, and supported tour participants with bike maintenance services and safety information. Through this partnership, we have connected with a new segment of our customer base who are eager to explore and learn about Central San’s wastewater collection system by bicycle.
POLLUTION PREVENTION AWARD WINNER
EUROPEAN AUTOSERVICE
Walnut Creek
Owners Tom and Petra Kasan run a clean, well-organized vehicle service facility. They handle fluids with care, using roll-around catch pans for oil changes and placing absorbent material and metal pans under every car, regardless of the work being performed, to catch incidental leaks. This proactive approach prevents floor spills and minimizes the discharge of polluted mop water to the sanitary sewer system. They are equally meticulous about hazardous waste storage to prevent any spills to the stormwater system. Additionally, Tom created a process for drip-draining containers to reclaim usable products and minimize fluid and plastic waste. We applaud European Autoservice for going the extra mile to prevent pollution and protect our water environment!
See page 15 for how to play!
Nice! Get a boost from a pumping station!
Oh no! Someone flushed a toy. Move another player back 1 space.
Good job! Throw trash in the bin rather than the toilet. Move forward 1 space.
Oops! Get tangled in a wipe in a pipe. Move back 2 spaces.
Way to go! Encourage your family to flush only the 3 P’s (pee, poop, and toilet paper). Move ahead 3 spaces.
Well done! Use a grease scraper or wipe dishes before washing. Move ahead 2 spaces.
Nice! Get a boost from a pumping station!
Nice! Central San maintenance crew clears a clog. Take another turn!
Oh no! Get caught in a FOG clog. Miss a turn.
Oops! Get tangled in a wipe in a pipe. Move back 2 spaces.
Right on! Join a Central San bike tour. Ride forward 2 spaces.
LEARN MORE ABOUT US!
CENTRAL SAN ACADEMY
Take a deep dive into the world of wastewater at the next session of our award-winning citizens’ academy. Learn all about the work we do, from collecting and cleaning your wastewater to preventing pollution, recycling water, piloting new technologies, and much more. Sign up for our email list and be among the first to be notified when we announce our next session. Learn more and subscribe at: centralsan.org/academy
PUBLIC TOURS
Join us for a guided walking tour of our wastewater treatment plant in Martinez and see firsthand how we clean millions of gallons of wastewater every single day. Or, grab your bike and “go with the flow” on a family-friendly bicycling tour following our wastewater infrastructure along the Iron Horse Trail. Visit centralsan.org/tours for details about upcoming tours.
SPEAKERS BUREAU
Looking for a speaker for your group or event? We may be able to help! Central San offers free presentations on pollution prevention and the world of wastewater. Talks can be in-person or virtual and tailored to your group’s interests. For more information, please contact Ben Lavender at blavender@centralsan.org or (925) 335-7723.
SAVE THE DATE!
SATURDAY, JUNE 13, 2026, 10AM–2PM
Mark your calendar for a free, all-ages, community-wide event with games, food, and fun!
KIDS’ PAGE:
HOW TO PLAY POOPS & PIPES
Whenever you flush the toilet, brush your teeth, or take a shower, all that water flows down the drain and travels through miles of pipeline to Central San. It’s our job to make sure all that dirty water is clean before we return it to the environment. But before we can clean your water, we need every drop to make it to our treatment plant. Sometimes, people flush things that can clog our pipes and stop the water from passing through. You can help make sure your dirty water reaches Central San safely by being careful about what goes down the drain.
Our Poops & Pipes game lets you follow along the path that your water takes from your home to our treatment plant. Can you be the first player to make it all the way to Central San?
HOW TO PLAY
Cut out all the game pieces on this page. Glue or tape the “die” around an empty toilet paper tube.
Have each player pick their game piece and place it on the “start” space. (Find the game board on pages 12-13.)
When it’s your turn, “roll the dice” by tossing the toilet paper tube. When the tube stops moving, see what number is on top and move your game piece ahead that many spaces.
If you land on a space with words, follow the instructions.
The first person to make it all the way to the treatment plant wins!
5019 Imhoff Place, Martinez, CA 94553
WE ARE HERE TO HELP
General Information (925) 228-9500 or CentralSan.org
Sewer Overflows (925) 933-0990
Household Hazardous Waste InfoLine (800) 646-1431 or CentralSan.org/HHW
Recycled Water Fill Station InfoLine (925) 335-7717
Sewer Connection Permits/Permit Counter (925) 229-7371
Community Information Line (925) 335-7702
Student Education Programs (925) 335-7723 or CentralSan.org/Learn
Environmental Compliance (925) 229-7288
Report Illegal Discharges Into Sewer System (925) 229-7288 (during business hours); (925) 229-7214 (after hours)
Treatment Plant InfoLine (Report Odors) (925) 335-7703
Employment Opportunities CentralSan.org/Careers
The Central Contra Costa Sanitary District PIPELINE
Written and designed by Central San staff to communicate pollution prevention messages to the people and communities we serve.
Ann Vallée, Editor, Writer
Kelsey Lansang, Graphic Designer
Joseph Zumbo, Photographer
View archived issues at CentralSan.org
Please share or recycle this newsletter.
Board meetings are open to the public and are usually held on the 1st and 3rd Thursday of each month at 2:30 p.m. in the Central San Board Room, 5019 Imhoff Place, Martinez. Meetings can be live-streamed at centralsan.org
Central San serves nearly half a million customers within its 146-square-mile service area.
Wastewater collection & treatment; Household Hazardous Waste (HHW) disposal.
Wastewater treatment & HHW disposal in Concord & Clayton by contract.
HHW disposal only.
Central San headquarters, treatment plant, HHW Facility & Residential Recycled Water Fill Station.
SUISUN BAY
CONCORD
MARTINEZ
PLEASANT HILL
CLAYTON
WALNUT CREEK
LAFAYETTE
ORINDA
MORAGA ALAMO
DANVILLE
SAN RAMON