By Giovanni Longo, third-generation master plumber and certified Flood Mitigation expert, Flood Brothers Plumbing
Forecast note (as of Nov 5, 2026): NOAA’s Climate Prediction Center has an El Niño Advisory in effect and expects a strong-to-very strong El Niño through January–March 2027, with chances remaining above 83% (CPC ENSO discussion, Oct 8, 2026; CPC status update, Nov 2, 2026). The National Weather Service in Los Angeles (AFD 12:43 PM PST Nov 5) keeps dry offshore weather through about Wednesday, a chance of light rain Thursday, Nov 12, then wet and unsettled weather from about Friday, Nov 13 into that weekend, with ensembles showing decent chances of widespread 1+ inch totals though timing and amounts remain uncertain (NWS Los Angeles AFD). NWS San Diego likewise flags a large trough late next week with substantial rain possible but low confidence in the details (NWS San Diego AFD). El Niño raises the odds of a wet winter, but it doesn’t guarantee one. Check weather.gov/lox before each storm.
"We’re on a hill, so we won’t flood." I hear it every winter. On a hill, water doesn’t pile up the way it does in a valley. Instead it runs, fast, carrying leaves and soil with it, and it finds every low spot on its way down. Some of the worst storm calls I’ve handled were hillside homes.
Why hill homes get hit
A hillside lot catches water from everything above it. That water hits the back of a retaining wall, runs down the driveway, and pours toward any door or lower floor set into the slope. When the drains clog with debris, the water goes wherever gravity sends it, often into the garage or a lower bedroom.
This guide covers the basics. I’ve also written separate posts for Hollywood Hills, Calabasas, Sherman Oaks, Studio City, Tarzana, Encino, Woodland Hills and Bel Air and Beverly Hills.
The hillside basics I check on every hill home
- Runoff from above: water from the slope, the street and neighbors’ lots all lands on you.
- Retaining walls: weep holes and the drains behind the wall have to flow. When they clog, water pressure builds up behind the wall.
- Debris in drains: brush, leaves and soil wash into area drains and plug them fast.
- Driveway runoff: steep driveways carry water straight to the garage.
- Lower floors: rooms set into the hillside take water through walls and doors.
Warning signs that mean "leave and call 911": cracks opening in the ground or walls, tilting trees or fences, sudden mud or debris flow, or doors that suddenly stick. A pump doesn’t fix a moving slope. Follow evacuation orders from your city or county.
The pump setup for a hillside home
On a hill, gravity does part of the work. Put the pump at the low spot where water collects, usually the garage threshold, a lower patio or a window well. Then run the hose downhill to the street. If the curb sits above the low spot, buy a pump rated for that lift. Full guide: pump, hose and outlet.
Safe when it’s set up right: the electrical part
Water and electricity can mix safely only when you set them up correctly. Here’s how I set up every pump:
- Plug into a GFCI-protected outdoor outlet only, and test it first: press TEST (power should cut off), then RESET. If it won’t trip or won’t reset, don’t use it.
- Use an outdoor-rated, heavy-gauge extension cord (12 or 14 gauge), as short as you can get away with. Skip thin indoor cords and power strips.
- Keep every plug and connection off the ground and dry. Hang it on a hook, set it on a bucket, or put it in a weatherproof connection box.
- Never handle the pump, cord or plug while you’re standing in water.
- Unplug before you touch, lift or move the pump. Every time.
- If water reaches an outlet, appliance or your electrical panel, get out and stay out. Call a licensed electrician or your utility. Don’t try to pump your way out of that one.
Learn more about our service in Los Angeles and about water damage restoration.
Need a hand before or during the storm?
Call or text 855-840-7800. A live person answers 24/7, and we offer same-day service. Flood Brothers Plumbing is licensed, bonded and insured (CA License C36-985487), we’ve been at this for more than 15 years, and we work directly with your insurance company. If water already got in, see our water damage restoration service: water removal and drying, odor treatment, tarps and board-ups.
Gio’s $99 Special
Before the El Niño rains and the holidays, get a sewer mainline snake plus camera inspection for $99. Mention "Gio’s $99 special" when you call or text 855-840-7800. Mention the special when booking; valid through 12/31/2026. See Gio’s $99 Special.
FAQs
My house is on a hill. Can it really flood?
Yes. Runoff from above, clogged retaining wall drains and steep driveways send water into garages and lower floors.
What should I check on a hillside property before the rain?
Retaining wall weep holes, area drains, gutters and downspouts, and the drain at the bottom of the driveway.
Will a pump help on a hillside?
Yes, at the low spots: garage thresholds, lower patios and window wells. Run the hose downhill to the street.
When is it too dangerous to stay?
If the ground, walls or trees are moving or cracking, or if mud starts to flow, leave and call 911. Follow evacuation orders.
