Forecasters are watching a strong El Niño build in the Pacific this year, and it’s raising real questions for San Francisco property owners. What does that actually mean for your building, and what should you do about it before the rain arrives?
NOAA’s Climate Prediction Center now puts the odds of a strong-to-very-strong El Niño this winter above 80 percent. That doesn’t guarantee a flood year. But history is clear on one point: Northern California has never landed in the driest third of winters during a moderate-to-strong El Niño event. The safer bet is to prepare your property now, while crews and materials are still easy to schedule.
Why El Niño Matters for Your Building
El Niño winters don’t always bring steady rain. They tend to bring bursts: a string of atmospheric river storms with little dry time in between. That pattern is hard on buildings in specific ways. Drainage systems sized for ordinary storms get overwhelmed. Ground that’s already saturated has nowhere left to send the next round of water. Small gaps in your building envelope that never caused problems in a normal year suddenly do.
For San Francisco specifically, that means the usual suspects: roof and gutter systems, exterior stairs and decks, window and door seals, and any spot where water has pooled or intruded before.
Roof and Gutter Systems
Clogged gutters and downspouts are one of the most common causes of water damage during a wet winter. Leaves, debris, and old sealant failures let water back up under roofing material instead of draining away.
- Clear gutters and downspouts before the first major storm
- Check that downspouts direct water well away from the foundation
- Look for cracked, lifted, or missing roofing material
- Inspect flashing around chimneys, vents, and roof penetrations
Decks and Outdoor Staircases
San Francisco’s outdoor staircases take a beating in a wet winter, and they’re already under close regulatory scrutiny through Section 604 and SB 721 compliance requirements. Standing water, soft wood, and rusted hardware are red flags that get worse fast once the rain starts.
- Check for soft, splintering, or discolored wood on treads and stringers
- Look for rust or corrosion on structural hardware and connectors
- Confirm drainage slopes water away from the structure, not toward it
- Address any deferred repair flagged in a recent inspection before winter
Exterior Painting and Building Envelope
Paint isn’t just cosmetic. It’s a big part of what keeps water out of your building’s walls. Cracked, peeling, or thin coatings let moisture behind the surface, where it can sit for months before anyone notices.
- Inspect exterior walls for peeling, bubbling, or cracked paint
- Recaulk around windows, doors, and trim where seals have failed
- Check that exterior wood surfaces are still fully sealed
Foundation and Drainage
Because El Niño storms tend to arrive in close succession, saturated ground is often the real risk, not any single storm. Water that can’t drain around your foundation will find the path of least resistance, and that’s usually into a basement, garage, or ground-floor unit.
- Grade soil and landscaping away from the foundation where possible
- Clear storm drains and area drains near the building of debris
- Check basements and ground-floor units for past water staining
The Case for Acting Early
Every property owner in San Francisco is watching the same forecast. Contractors book up fast once storms actually start, and a small gutter repair now is a lot cheaper than water damage remediation in January. A pre-winter walkthrough is the fastest way to find out where your building is exposed before it costs you.
For more on how NOAA is tracking this year’s El Niño, you can read the Climate Prediction Center’s latest ENSO discussion.
Not sure where your building stands heading into a strong El Niño winter? Maven Maintenance offers free pre-storm inspections for San Francisco apartment buildings, condos, and TICs. Request a bid today and get ahead of the rain.