Swim at
the Inkwells
The familiar West Marin swimming-hole idea deserves a careful second look. Here is what to check before you go, when to stay out, and how to enjoy the area without entering the creek.
By Best of Marin Staff · Reviewed
What—and where—are the Inkwells?
A creek landscape, not a managed swimming pool
The Inkwells is a rocky creek feature near Shafter Bridge in Lagunitas, off the Sir Francis Drake Boulevard corridor. Marin Water’s Lagunitas Creek Stewardship Plan locates it just above the meeting of San Geronimo and Lagunitas creeks. That is more precise than treating every nearby stretch of water as the same swimming spot.
The appeal is easy to understand: shade, sculpted rock, and the feeling of finding a small pocket of wild Marin. But a place can be beautiful without being an appropriate place to get in the water. Popularity, photographs, and a long history of visits are not safety certifications.
Plan for an informal natural setting, not a lifeguarded facility. Do not count on supervision, rescue equipment, easy entry and exit, changing rooms, or an accessible route down to the water.
Three checks before you leave home
1. Water quality: read the date, not just the color
The County monitoring program explains that samples are snapshots and conditions can change. Results are posted during the April–October monitoring season. An old result, missing sample, or lack of a sign is not proof of clean water.
Find the Inkwells row, read the newest completed week, and follow the advisory. You can also check the County’s recorded water-quality information at 415-473-2335. Do not substitute a social-media post or a stranger’s reassurance for current official information.
2. Access: nearby land can have different rules
We have not verified a blanket, year-round permission to swim at the Inkwells. Marin Water prohibits swimming in its reservoirs and streams. Nearby Samuel P. Taylor State Park closes creek access December 1–June 15 to protect fish.
These are land-manager rules, not interchangeable labels for every bank and pool. Confirm which rules apply to the exact access point and water you intend to use. Do not assume the end of a seasonal closure gives permission everywhere. If you cannot confirm access, stay out.
3. Weather and flow: no fixed safe season
Heavy rain can bring contaminated runoff and changing flows. The CDC’s natural-water guidance recommends checking advisories especially after rain and staying out of discolored, unusually cloudy, or foul-smelling water. Visible scum or suspected algae is another reason to avoid contact.
Do not treat a sunny afternoon, low-looking water, or a fixed number of dry days as an all-clear. If conditions are uncertain, the right decision is a different activity—not a test swim.
The warnings that matter most
No jumping. No diving. No bridge stunts.
Do not jump or dive from rocks, banks, or the bridge. Dark water can hide submerged rock and debris; depth and landing conditions can change. Seeing another person jump successfully tells you nothing reliable about your next landing.
Serious head or spinal injury, drowning, and death are possible. This guide intentionally does not identify launch points, landing zones, or supposedly safe jump heights. Skip the stunt even if it appears in an old video.
Cold water, current, and slippery rock are different risks
Natural water can hide currents, obstacles, and abrupt changes in depth. Cold water can impair your ability to swim, while slick rock can make getting out harder than getting in. Treat all of these as potential hazards, not conditions we have measured at this site today.
Do not scramble onto wet ledges for a photo or let a crowded bank push you closer to the edge. A sturdy shoe can improve footing, but it cannot make an unsafe approach safe. If the route requires a risky climb, turn around.
Water quality is a health issue, not a matter of toughness
The CDC warns that natural water can transmit illness when swallowed and cause infections through open wounds. Stay out if you have diarrhea or an open wound; people with weakened immune systems should seek individual medical guidance before natural-water swimming.
Do not drink creek water or assume clear water is free of germs. Keep pets out of questionable water too. A brief dip or wade still involves contact; shortening the exposure does not cancel an advisory.
Make the visit low-impact—or change the plan
Parking is not permission to enter the creek
Use only legal, signed parking. Respect time limits, private property, road shoulders, gates, and emergency access. Do not stop on a bridge or cross traffic casually because you can see the water nearby.
Marin Water notes that the nearby Leo T. Cronin Fish Viewing Area has a small lot that fills quickly. It is a fish-viewing destination, not a promise of swimming access or overflow parking. If you cannot park legally, move on.
Pack for a creekside outing, not a party
Bring drinking water, a charged phone, a downloaded map, grippy footwear, a warm layer, and a bag for all rubbish. Keep glass and loud speakers out of the outing. Avoid alcohol and other impairing substances around water.
Stay on authorized routes, leave rocks and vegetation in place, and never build little dams or disturb fish. Keep the group small enough to move courteously past others. This is habitat and a neighborhood, not a private backyard.
Have a plan if something goes wrong
Know your location and the nearest legal access point before approaching the creek. Do not assume you will have reliable phone reception or that help can reach the bank immediately.
If someone is in distress, call 911 and follow dispatcher instructions. Do not enter hazardous water and become a second victim. The American Red Cross recommends reaching or throwing assistance from a safe position rather than entering the water. Water-safety and CPR training are worth arranging before any future swimming outing.
A good West Marin day without swimming
Choose redwoods, a walk, and a picnic
With an advisory in place, make the outing a dry-land one. Our Samuel P. Taylor back-roads guide offers a relaxed park visit with a flexible walk and picnic. Check park conditions, pay applicable entry fees, and follow trail and creek restrictions.
Or pause in Fairfax before a scenic drive and leave the water for another day at a supervised facility. Agree on this backup before you depart so nobody feels pressured to swim simply because you made the trip.
The best local advice is sometimes permission to change your mind. A shaded walk and lunch can still be a memorable afternoon; entering questionable water is not what makes it count.
Inkwells swimming questions
Is it safe to swim at the Inkwells today?
This article cannot confirm today’s conditions. At our October 23, 2026 review, Marin County listed AVOID for the week of October 19. Avoid water contact while an advisory applies, check the latest official results, and obey all restrictions. An acceptable bacteria result does not establish that swimming is safe or permitted.
Can I jump or dive from the rocks or bridge?
No—do not jump or dive. Depth, submerged rocks, debris, and water conditions cannot be judged reliably from above. Other people jumping does not make it safe. Serious injury or death is possible.
Is this a good swimming spot for young children or beginners?
We do not recommend it for children learning to swim, non-swimmers, or anyone wanting a supervised swimming area. Choose an operating, lifeguarded pool instead. Adults must closely supervise children even when staying on shore.
Does clear water mean clean water?
No. Harmful germs can be present without an obvious visual warning. Use current official advisories rather than appearance, crowd size, or an old review. Avoid swimming after heavy rain.
Does swim at your own risk mean swimming is allowed?
No. It is a warning about personal risk, not permission to enter closed or restricted water. Check with the land manager, obey signs, and stay out if access or conditions are uncertain.