West Marin's coastal communities, including Stinson Beach, Bolinas, Inverness, Point Reyes Station and the shores of Tomales Bay, have many second homes and vacation rentals. When those homes sit closed up through foggy, rainy months, indoor humidity can climb, and owners sometimes arrive to a musty smell and mold on walls, furniture or bedding. Here's how to prevent it.
The CDC recommends keeping indoor humidity no higher than 50% and fixing leaks promptly (CDC). The EPA emphasizes that moisture control is the key to mold control (EPA).
West Marin is exposed to coastal storms, and Stinson Beach homes, including the Seadrift area, face ocean surge and coastal flooding. As of the Climate Prediction Center's October 8, 2026 ENSO discussion, an El Niño Advisory is in effect, and NOAA says a strong-to-very strong El Niño is likely through January–March 2027. NOAA is also careful to say that a stronger event makes El Niño-like impacts more likely, not guaranteed. El Niño winters have historically tilted Northern California toward wetter conditions, but individual seasons vary, and no outlook can tell you when or where a specific storm will hit. Watch the CPC seasonal outlooks and the National Weather Service Bay Area office for forecasts as the season unfolds.
After big storms, have someone check:
Sign up for AlertMarin for your West Marin address. It allows up to five Marin addresses, so you can include your second home.
If you rent your home short-term or long-term, mold and moisture can become disputes. Keep records of inspections, maintenance and repairs, and address problems promptly. California has habitability requirements for rentals, so consult a qualified professional about your obligations.
Many service providers are based in central Marin or beyond, so response times to West Marin can be longer. Plan ahead: line up a provider before you need one. Our West Marin page has more about local mold factors.
A handful of inexpensive connected devices can make remote ownership far less stressful. Water leak sensors under sinks, near the water heater and by appliances send alerts to your phone. Smart humidity and temperature monitors let you watch conditions from home and spot rising humidity before mold starts. Automatic water shutoff valves can close the main when they detect a leak or unusual flow. Smart plugs or thermostats can run dehumidifiers and heaters on a schedule. Check that your home's internet service is reliable enough for alerts, and make sure your local contact knows what to do if an alert goes off.
Submit a request to connect with an independent provider serving West Marin for mold inspection or remediation.
Control humidity with a drained dehumidifier and monitor, shut off water or use an auto shutoff valve, and arrange post-storm checks.
The CDC recommends no higher than 50% indoors.
For long absences, shutting off the main or using an automatic shutoff valve reduces leak risk.
They can close the main water when a leak or unusual flow is detected; install per manufacturer guidance.
Some devices use cellular connections; otherwise rely on a local contact for checks.
This article is general information, not legal, insurance or medical advice. Sources are linked in the text.