On Oct. 22, The Press reported that invasive golden mussels have spread through the Delta to the Discovery Bay Marina and Orwood Resort in Brentwood. The same story says the mussel showed up in Lake Del Valle in September and in Antioch's Contra Loma Reservoir the year before. It also says researchers have not found a way to get rid of it.
If your boat lives at a backyard dock or in a slip, the rules that matter most are at the launch ramps of the lakes you trailer to. Most agencies that run inspected lakes within driving distance honor only their own band or seal. Lake Berryessa accepts some outside seals, but only under conditions a Delta boat has to plan around. Once a boat leaves Discovery Bay, it's mostly on one lake's terms at a time.
The lakes already treated Delta boats as suspect
The East Bay Regional Park District inspects boats at Contra Loma, Del Valle, Lake Chabot, Quarry Lakes and Shadow Cliffs. Every inspection starts with a vessel history survey. That survey flags any boat that has been in mussel-infested water during the past 30 days, and the district's list of that water names "the Delta" outright, alongside San Luis Reservoir, Bethany Reservoir and Lake Mead.
So a confirmed sighting at the Discovery Bay Marina doesn't create a new category for local boats. They were already in it. A boat that spends its weeks tied up off a Discovery Bay backyard has been in the Delta during the past 30 days by default. That's true of a kayak or paddleboard launched off the same dock, too. The district's inspections cover kayaks, canoes, inflatables and "any form of floating board."
The sightings in the region have been building for more than a year. In 2025, the California Department of Fish and Wildlife recorded golden mussels on the underside of slips at New Bridge Marina in Antioch and at a yacht club in Pittsburg, and in Grant Line Canal and Upper Old River. In June 2026, CDFW confirmed its northernmost detection so far, at the Port of West Sacramento. CDFW keeps a live sightings map that it updates as new detections are confirmed.
A band from one lake doesn't open the next one
Here's where living on the water in Discovery Bay starts to shape the rest of your boating calendar. On Sept. 21, 2026, the park district announced that anyone launching at Lake Del Valle now faces a 30-day quarantine before the boat can go into any other district water. Contra Loma boaters were already under the same rule. A boat that launches only at Del Valle and comes back with its Del Valle band intact skips the quarantine, but only for Del Valle. The district has used lake-specific bands since summer 2025.
The other agencies in reach have each built their own version.
| Lake | Operator | What a trailered boat faces |
|---|---|---|
| Lake Del Valle, Contra Loma | East Bay Regional Park District | Inspection at $10 for motorized boats and $5 for car-top craft. Launching at either lake means 30 days before any other district lake. |
| San Pablo Reservoir | EBMUD | Inspection, banding and a full 30-day quarantine. No other reservoir's band is accepted, and after launch the boat is limited to EBMUD waters. |
| Lake Berryessa | Solano County Water Agency program | A 30-day red-seal quarantine or approved hot-water decontamination, for every motorized boat, new ones included. |
| New Melones Lake | U.S. Bureau of Reclamation | A red wire seal linking boat to trailer for 30 days, then a green seal on the way out. |
| Lake Tahoe | Tahoe Boat Inspections | Inspection and decontamination for motorized boats arriving from other areas. |
| Los Vaqueros Reservoir | Contra Costa Water District | No outside boats. Rental boats only. |
Taken together, the table shows that most of these seals work like a passport stamp good for a single country. EBMUD's San Pablo Reservoir won't honor another reservoir's band. The park district honors its band only at the lake that issued it. The New Melones seal system applies only at New Melones. Lake Berryessa is the exception. It accepts a 30-day red quarantine seal from any agency if the completed quarantine is recorded in the Watercraft Inspection and Decontamination database, known as WID, and it accepts Lake Tahoe blue seals. A red seal from another lake that's still inside its 30 days won't get a boat onto Berryessa. Among the conditions Berryessa lists for honoring an outside red seal, one is that the lake that applied it hasn't tested positive for quagga, zebra or golden mussels, and Del Valle now has. EBMUD also set Oct. 30 as the last day of San Pablo's 2026 launch season, with launches running Thursday through Sunday and holidays until then.
Some lakes do let a boat skip the 30-day wait. At Lake Berryessa, the Solano County Water Agency lists approved hot-water decontamination providers that include Markley Cove, Pleasure Cove, Putah Canyon and Gone Fishin' Marine. A boat that finishes quarantine launches with the red seal still on and gets a green seal on the way out. That green seal lets it come back later without repeating the quarantine. The agency's Lake Solano County Park station closed for the season on Sept. 7, 2026, and is set to reopen in spring 2027. The New Melones Lake Marina advertises fee-based decontamination for same-day access. The Bureau of Reclamation's New Melones boating page carries an update date of 2020, so the procedure there is worth confirming with the lake before a 2026 trip. At Tahoe, a boat last launched at Tahoe with an intact Tahoe seal can return without reinspection.
"Dry" means something specific for a boat that lives in the water
Every one of these programs depends on the boat arriving dry. For a trailered boat that sits in a garage between trips, that's easy. For a boat that comes out of Discovery Bay's water the morning of the trip, it isn't.
The California Division of Boating and Waterways spells out the steps, and the park district's inspectors check the same places:
- Inspect and clean the hull, motor and trailer, and throw out any plants, debris or animals.
- Drain the motor and lower outboard unit, the ballast, the live well, buckets and anything else that holds water. Drain the bilge, too. DBW says bilge water contaminated with petroleum has to be handled as hazardous waste.
- Dry everything. DBW recommends at least five days in warm, dry weather and up to 30 days in cool, moist weather, with compartments open and standing water sponged out.
- Leave the motor alone for a few days before the trip. The park district says a freshly flushed motor can hold trapped water, so it suggests flushing at least five days ahead and leaving the motor down so the intakes drain.
- On launch day, check the bilge, live wells, engine compartment and dry storage again, and tilt the motor up and down several times.
The timing matters more in Discovery Bay than for inland boaters. The fall and winter months are when DBW's guidance stretches toward the 30-day end of the drying range. The park district's penalty for showing up wet is a denied launch and a five-day wait before trying again. Discovery Bay Marina, which DBW lists as a public marina with launch, dry storage, washdown, haul-out and bilge pumpout services, sits close to most of the town's docks for the haul-out and washdown part of that routine.
Even the experts don't have a firm number on drying. "Some water managers are having success drying them out, but we don't know for sure how long that takes," Wyatt Moore, supervising naturalist at Big Break Regional Shoreline in Oakley, told The Press. That uncertainty explains why so many agencies fall back on a flat 30-day quarantine instead of trusting a visual check.
The boat that stays in the slip has its own maintenance math
Mussels aren't only a problem at the lake gate. CDFW's fact sheet says colonies impede water flow, clog pipes and foul watercraft motors. The Press reported that the mussel grows on virtually any surface, including piers, boats and pumps.
What that looks like on a single boat showed up farther up the Delta. In December 2025, KMPH reported on a Stockton Sea Scouts vessel that came out of the water heavily fouled. Mussels had clogged its sonar and its raw-water engine-cooling intakes, and the story described more hull drag and lower fuel efficiency as possible effects.
CDFW's current advice to Delta boaters is about the moment equipment leaves the water. Inspect it each time, remove organisms, drain ballast, bilge and live-well water, and dry it until no moisture is left. The agency hasn't published a separate schedule for boats moored year-round. For an owner at a backyard dock, the practical version so far is that every haul-out doubles as an inspection. Anyone who spots a mussel can report it through CDFW's golden mussel page.
Staying home has never been simpler
All of these rules apply when a boat leaves the Delta. A boat that stays on Discovery Bay's own water this season doesn't need a seal, a band or a quarantine. December is the busiest month for that kind of boating here.
The Discovery Bay Lighted Holiday Street Parade, now in its 24th year, is set for Saturday, Dec. 5, from 5 to 10 p.m. One week later, the DBYC Lighted Boat Parade runs Saturday, Dec. 12. Boats assemble on Kellogg Creek just off the point of Newport Lane, and the parade starts at 5:15 p.m. It winds through every other bay of Discovery Bay and ends in Marina Bay just past F dock. This year's theme celebrates America's 250 years. The parade is open to any boater who registers. Every boat needs a VHF radio on board, and skippers have to attend a meeting on Dec. 6 at 7 p.m. That's where the wristbands for the post-parade awards, food and drinks at the Disco Bay Yacht Club on Marina Road are handed out.
Lake rules and fees change with each new detection, so treat this as general information. Check with the agency that runs a lake before you tow, and for questions about your own vessel, ask a marine professional.
At Bogosian & Co., we keep track of what changes on Discovery Bay's water because so many of our neighbors' lives are built around it, from the dock out back to the December parade. If you'd like to talk through what owning a home on the water here looks like today, we'd be glad to sit down with you. Schedule a Free Consultation.
