When water gets into your home, the first day matters more than any other. Water keeps moving, into wall cavities, under flooring, into insulation, and the longer materials stay wet, the more you'll end up replacing. The CDC advises cleaning up and drying out your home fully and quickly, within 24–48 hours, after a flood, in part to limit mold growth (CDC). Here's a practical sequence for the first 24 hours.
Before you do anything else, make sure everyone is safe.
If it's a plumbing problem, shut off the main water valve. In many Marin homes it's near where the line enters the house, in the garage, a front-yard box or the crawlspace. If it's a water heater, there's usually a shutoff on the cold supply line above it. If it's storm water coming through the roof, put buckets down and, if it's safe and the rain allows, a tarp may be needed. Don't climb on a wet, steep roof yourself; see emergency tarping on our roofing site. If it's outside water rising, there may be little you can do but protect people and valuables and wait for it to recede.
Before you move or throw away anything (except for safety reasons), take photos and video:
The California Department of Insurance's residential guides include a claims guide and a home inventory guide that are worth skimming now.
Report the claim to your insurance company as soon as you reasonably can. Ask what they need from you, whether they have requirements about who does the mitigation work, and write down your claim number and the name of everyone you talk to.
At the same time, contact a water damage restoration provider. Most policies expect homeowners to take reasonable steps to prevent further damage, and professional extraction and drying is usually the biggest step. You can request a referral here to an independent local provider. Read our guide on choosing a contractor and checking a CSLB license before you sign anything.
A restoration provider will typically:
Ask for a written scope, daily moisture readings, and photos. These help with your insurance claim and give you confidence that drying is actually complete.
Crawlspaces. Water in a crawlspace is easy to ignore because you don't see it. But a wet crawlspace raises humidity in the whole house and can lead to mold on floor framing. This is common in older homes in San Anselmo, Fairfax and Mill Valley. See our flood cleanup page.
Creek and tidal flooding. Homes near Corte Madera Creek, San Rafael Creek, Novato Creek or the bay may get outside floodwater, which is treated as contaminated and often isn't covered by standard homeowners insurance. Check whether you have flood insurance through FloodSmart.gov or a private carrier.
Vacation and second homes. In Stinson Beach and West Marin, leaks in empty homes can run for days. Consider a smart water-leak sensor and automatic shutoff valve.
Even with good drying, watch for musty smells or spots over the next few weeks, especially in closets, behind furniture and in crawlspaces. Our sister site covers mold prevention after a flood or leak in detail.
Restoration professionals often group water by how contaminated it is. Clean water comes from a sanitary source like a broken supply line. Gray water has some contamination, such as discharge from a washing machine or dishwasher. Black water is grossly contaminated: sewage backups and floodwater from creeks or storm drains. The category affects what can be dried and saved and what has to be removed, as well as what protective gear workers use. Clean water can degrade into a worse category if it sits, which is one more reason to move fast.
The CDC recommends cleaning up and drying fully and quickly, within 24–48 hours after a flood, to help prevent mold.
Ask your insurer, but most policies expect you to take reasonable steps to prevent further damage. Document everything with photos first.
Water from creeks, storm drains or sewers can be contaminated. Wear protective gear and keep children and pets away.
Often yes, depending on the extent and the water category; ask your provider and insurer.
Treat it as contaminated. Avoid contact and get professional cleanup.
This article is general information, not legal, insurance or medical advice. Sources are linked in the text.