San Francisco is known the world over for its scenic steep hills. While the city is typically dry May through October, the rainy season can bring heavy downfalls that can temporarily overwhelm the city’s stormwater runoff and sewer systems. Therefore, it’s important to protect your home and business regardless if you’re in a direct flood zone or not.
Starting in 2026, the City is here to help qualified residents to offset these costs with the Floodwater Management Grant Program. But before then, let’s explore your potential risk.
San Francisco flood zones
The city of San Francisco has created an urban flooding heat map that shows the areas most likely to flood in a severe storm. But all property owners should be well aware of any potential flood risks to their property.
- Elevation wise, where does the property sit in the neighborhood?
- In a heavy rain, where will excess water runoff most likely go?
- Where does the house, DADU, garage, or other structure you own sit on the lot?
- Are these structures uphill or downhill within the landscaping?
- What basements, crawl spaces, storage or living areas are susceptible to a few inches or more of floodwater?
- Do your gutter downspouts empty rain water into the sewer system, guide water to the street, or empty water into the yard?
- How clogged are the nearest storm drains on your street?
- Do you see litter, garage, or leaves when you peek inside?
- Does your property have a sump pump?
- Does your property have backflow prevention valves?
Now let’s tackle each of these one at a time.
Neighborhood Flood Risk
The lower your property is on the block, the higher the risk of stormwater damage. Take note of where water would likely enter your property from adjacent properties at higher elevations. If you’re near the base of the hill, where exactly are the stormwater drains located? Track how well they absorb runoff when it rains. If you notice a storm drain backup, be sure to report it to the city so they can clean it out. Within city limits you can dial #311, use the city’s SF311 mobile app or report an issue to the city’s website.
Property Flood Risk
Water will always flow downward to the lowest possible location. When you walk your property, take note of where these places might be. Is your home or any related structures built on a slab, basement foundation, or crawl space? How many inches or feet of standing water would it take to reach valued living space? Should water enter these low spaces, what systems are in place to pump it out?
Ace Plumbing and Rooter can install sump pumps in one or more strategic locations to best protect your home. The best sump pumps include battery backups since heavy storms often coincide with power outages. The pump can move water into the sewer line, the storm drain line, or out into the yard or street as local codes and zoning permits allow. We’ll do the research to ensure your system is compliant, plus we’ll arrange the city inspection for you. Best of all, you may be applicable for city grant money to cover all or part of this cost.
Sewer Line Lateral Maintenance and Repair
You don’t want to wait for a major storm to realize that the sewer line pipes that connect your property to the city connection have been compromised. Earthquakes, erosion, and other ground shifts, tree root intrusion, nearby construction, pipe corrosion, and sediment buildup could all lead to cracks or ruptures along the line, leaving your sewage with no place to go. ACE Plumbing and Rooter can scope your line and take note of any potential problems. We have spot repair, trenchless sewer line replacement, and full sewer line replacement strategies to provide you with the most cost efficient remedy.
Backflow Prevention – City Grant Eligible
When excess stormwater, litter, leaves, and other debris overwhelm the city sewer system, sewer backups are highly likely. This is why your house’s sewer line needs to have a working backflow prevention system, typically a series of valves that ensure the waste water that exits your property cannot flow back in. When a sewer line backup happens in an unprotected home, smelly sewage will back up through the toilets and sinks in your house starting with the lower levels, and rising up as blackflow pressure increases. Backflow prevention valves seal your home from this biohazard risk.
Additional Flood Protections – City Grant Eligible
ACE Plumbing and Rooter has completed many projects through this grant, and earned a place on the San Francisco Floodwater Management Grant Program’s “Contractor resource list”. ACE Plumbing and Rooter can provide a wide range of services to protect your home from flooding.
- Design and Installation of Regraded Driveways and Raised Planters to flow a surge of surface level storm water away from your house and garage and into city drains
- French drains and sealed external surfaces that flow above and underground water into sewer laterals
- Raising electrical outlets and other compromisable elements inside your garage to above likely flood levels
- Resurfacing garage and crawl spaces with easy to clean, bacteria-resistant materials that can be hosed off, mopped and dried after a minor flood without compromising the underlying slab and housing structure
- Floodwater barriers that can be deployed manually or activated automatically the moment floodwater is detected. These barriers can protect entry doors, first level windows, and garage doors.
Paperwork, Planning, Design and Construction – ACE has you covered!
While the city clearly spells out the process to obtain floodwater management grants, the process for determining eligibility, submitting a proposal, pulling permits, and managing construction can be overwhelming for many busy homeowners. That’s why ACE can support you through the process every step of the way. We can perform an initial assessment and discuss which strategies are eligible for grant payment and which would be solely your responsibility.
We never sell you products or services you don’t need and strive to be a trusted and reliable resource to help you create a flooding prevention strategy that best works for you.
