Water damage and mold after a leak or flood: first steps and cost

For Silicon Valley homes · Updated October 2026 · Sources below

Stop the water, make the area safe, and photograph everything before cleanup. Then dry it fast: the EPA says water-damaged areas should be dried within 24 to 48 hours to prevent mold. Small mold spots under about 10 square feet are usually a DIY job; larger areas or a lot of water damage call for a professional.

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Turn off power to wet areas at the breaker panel before walking in standing water. Keep people and pets away from sewage, and get fresh air if anyone feels unwell around mold.

The short version

Stop the water source and turn off power to wet areas first
Photograph and video the damage before you move or throw anything out
Dry within 24-48 hours to prevent mold (EPA)
Mold over about 10 square feet, or a lot of water damage: hire a pro (EPA)
Standard homeowners insurance does not cover flood damage (CA Dept. of Insurance)

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What it costs

Water damage restoration$1,383 - $6,369 (average $3,868)
Mold removal$1,100 - $3,400 (average $2,225)

Clean water from a supply line costs less to dry out than gray water or sewage. The size of the wet area and what has to be removed drive the price.

Typical ranges from published cost guides - mostly national figures. Bay Area prices usually run higher. Your actual price depends on your home and the job, and a pro gives you the real number. Source: HomeAdvisor cost guide (national) (Jun 2026). Have a quote? Check it with the Quote Explainer

Signs water damage is spreading

Stains, bubbling paint or soft drywall that keep growing
Warped or cupped floors, or carpet that stays damp
A musty smell
Visible mold spots on walls, ceilings or under sinks
Swollen cabinet bases or baseboards

What to do first

Stop the water: close the fixture valve or the main shutoff, and fix or cap the leak.
Make it safe: turn off power to wet areas at the breaker panel. If sewage is involved, keep people and pets away.
Document it: take photos and video of the damage room by room before cleanup, and keep damaged items for the adjuster if you can.
Report it to your insurer and make temporary repairs to prevent more damage. Keep receipts and a log of calls.
Dry it within 24-48 hours: open windows, run fans and dehumidifiers, and pull out wet carpet pads, insulation or ceiling tiles that can't be dried.

In Silicon Valley

Bay Area storms: Valley Water urges Santa Clara County residents to know their flood risk, download the county's AlertSCC emergency app, and know where to get free sandbags before a storm. It gave out 140,000 free sandbags in the winter of 2023-24.
California Department of Insurance: standard homeowners insurance does not cover flood damage. A new flood policy usually takes effect 30 days after you buy it, so don't wait for a storm warning.
The Department of Insurance also says to make temporary repairs after a loss to prevent further damage, and notes the first insurance check is often an advance, not the final payment.

Questions homeowners ask

What should I do first after water damage in my house?

Stop the water, turn off power to any wet areas, and photograph the damage before cleanup. Report it to your insurer, make temporary repairs to stop more damage, and start drying right away.

How fast does mold grow after water damage?

The EPA says to dry water-damaged areas and items within 24 to 48 hours to prevent mold growth. Porous materials like carpet and ceiling tiles that get moldy may have to be thrown away.

Can I clean up mold myself?

For a moldy area under about 10 square feet, the EPA says you can usually do it yourself: scrub hard surfaces with detergent and water and dry them completely. Hire a professional if there's a lot of water damage or mold covers more than 10 square feet. Never mix bleach with cleaners that contain ammonia.

Does homeowners insurance cover water damage?

It depends on the cause and your policy. Water damage is among the losses a homeowners policy may cover, but standard homeowners insurance does not cover flood damage. Report the loss promptly and ask your insurer what's covered before major demolition.

What photos should I take for an insurance claim?

Before cleanup, photograph and video each room, the source of the water, damaged walls and floors, and damaged belongings. Keep damaged items separate if you can, so an adjuster can see them.

How much does water damage restoration cost?

National cost guides put water damage restoration at about $1,383 to $6,369, and mold removal at about $1,100 to $3,400. Bay Area prices usually run higher, and sewage or a large wet area costs more.

Questions to ask the pro

How will you measure moisture, and how will I know it's dry?
What needs to be removed, and what can be dried in place?
Do you work directly with my insurance company, and what do I pay up front?
Is mold testing or mold removal included, or separate?
Who rebuilds the drywall, flooring or cabinets after drying?

Before you sign, check the contractor's license at cslb.ca.gov. How to hire a contractor in California

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