Forecasters have spent most of 2026 watching a developing El Niño in the Pacific, and many expect it to be a strong one. Strong El Niño winters have historically raised the odds of heavy, repeated rainstorms across Southern California. For San Diego renters, that means one thing: the leaks your landlord has been “meaning to fix” are about to be tested.
Many local families still remember the January 2024 floods, when neighborhoods from Southcrest to Shelltown took on water and hundreds of homes were left damp for weeks. Much of the mold we see in our practice does not start with a disaster, though. It starts with a small roof leak, a failed window seal, or a slow drip behind a wall that goes unrepaired through one rainy season and then another.
This guide explains what to watch for, what California law requires of your landlord, and the simple steps that protect both your family’s health and your legal rights.
Why Heavy Rain Leads to Mold Indoors
Mold needs three things to grow: moisture, a food source, and time. Drywall, wood framing, carpet padding, and ceiling tiles are all excellent food sources. Once building materials stay wet for roughly 24 to 48 hours, mold growth can begin.
During a wet winter, water enters rental housing through predictable paths:
- Roofs with worn or missing flashing, especially around vents and skylights
- Windows and sliding doors with failed seals or clogged weep holes
- Balconies and exterior walkways that drain toward the building instead of away from it
- Poor grading or blocked drains that let water pool against foundations and slab edges
- Plumbing and HVAC condensate lines that were already marginal before the storm
Water that gets inside a wall cavity may never be visible. Often the first warning sign is a smell.
Early Warning Signs Renters Should Not Ignore
Watch for these signs during and after every storm:
- A musty or earthy odor, especially in closets, bathrooms, or behind furniture
- Brown rings or bubbling paint on ceilings and upper walls
- Soft, swollen, or stained baseboards
- Condensation or water beading on the inside of windows that does not clear
- Carpet that feels damp or smells sour near exterior walls
- New or worsening headaches, congestion, coughing, or eye irritation that improves when you are away from home
That musty odor matters. The California Department of Public Health has recognized that visible water damage, damp materials, and mold odor are themselves indicators of a problem that should be corrected. You do not need a lab report to know something is wrong. Learn more in our guide to musty odors in your home.
What California Law Requires of Your Landlord
Every residential lease in California includes an implied warranty of habitability. Under Civil Code section 1941.1, a rental is not fit to live in if it lacks “effective waterproofing and weather protection of roof and exterior walls, including unbroken windows and doors.” Health and Safety Code section 17920.3 separately lists dampness of habitable rooms and visible mold growth as conditions that can make a building substandard.
In plain terms: keeping rain out is the landlord’s job. Once your landlord has notice of a leak or mold, California law expects a timely, proper repair. That means fixing the source of the water and correcting the damage, not just painting over the stain.
Five Steps to Take Before and During the Storm Season
1. Document the condition of your home now. Walk through with your phone and photograph ceilings, window frames, under sinks, and closets. Date-stamped photos taken before the rain are powerful evidence that damage appeared after a storm. See our tips on photos and video.
2. Report every leak in writing, every time. A phone call is easy to deny. Send an email or use your landlord’s online portal, describe what you see, attach photos, and keep a copy. Notice is one of the most important elements of a mold case, which is why we wrote an entire article on giving proper notice.
3. Limit the damage you can safely control. Move belongings away from wet areas, run fans or a dehumidifier if you have one, and put down towels to catch drips. Taking reasonable steps protects your property and shows good faith.
4. Do not let “we’ll send someone after the storm” become months. Write down each promised repair date. If a technician only wipes surfaces or paints over staining without drying the wall or fixing the leak, note that in writing too.
5. Pay attention to your health. Keep a simple log of symptoms and when they occur. If you or your children are having respiratory symptoms, see a doctor and tell them about the water damage at home.
When a Leak Becomes a Legal Claim
Not every leak is a lawsuit. A landlord who responds quickly, dries the area properly, and fixes the source is doing what the law requires. A legal claim typically arises when a landlord knows about water intrusion or mold and fails to correct it within a reasonable time, and a tenant’s health, belongings, or use of the home suffers as a result.
Depending on the facts, tenants may be entitled to recover for physical symptoms, medical expenses, damaged personal property, rent paid for a home that was not habitable, and other losses. Our article Can I Sue My Landlord for Toxic Mold? walks through how these cases work.
Frequently Asked Questions
Is my landlord responsible for storm damage inside my apartment?
Generally, the landlord is responsible for keeping the roof, walls, windows, and doors weatherproof. If water gets in because those systems failed, the landlord is usually responsible for fixing the source and the resulting damage once notified. Your own renter’s insurance may cover your personal belongings.
How fast does mold grow after a leak?
Mold can begin growing on wet building materials within 24 to 48 hours. That is why prompt drying is so important and why delay by a landlord can turn a simple leak into a serious mold problem.
Can I withhold rent if my roof leaks during El Niño?
Withholding rent carries real eviction risk and should only be considered after speaking with an attorney. California offers several remedies, and the right one depends on your situation.
What if the governor declares a storm emergency?
If a disaster is formally declared, a newer California law (SB 610) adds specific cleanup duties for landlords, including addressing mold and water damage. See our post on SB 610 and disaster cleanup.
Talk to a San Diego Mold Attorney Before the Damage Spreads
For nearly 50 years, Thompson Injury Law has focused on one thing: helping Southern California families harmed by mold and water-damaged housing. If rain is coming into your home and your landlord is not fixing it, call attorney Anthony D. Thompson at (619) 615-0767 or request a free mold case evaluation. Hablamos español.
This article is for general information only and is not legal advice. Reading it does not create an attorney-client relationship.
