LA rainy season prep. Yard drains & sewer backups.
Southern California goes months without rain and then gets a lot at once. Drains that sat dry all summer fill with leaves and dirt, and the first big rains find every weak spot. A couple of hours in October or November prevents most rain-related flooding and backups.
Updated October 2026 · Rooter Pros, Burbank-based mobile plumber · CSLB #917630
What you'll need
Basic yard tools:
- Gloves & a trowel or scoop — for grates and catch basins
- Garden hose — to test-flush drains
- Hand drain snake — for short area-drain runs
- Flashlight — to check grates and the cleanout
- Ladder (with a helper) — only if you can safely reach gutters
Before the first big rain.
Work from the roof down to the street — water follows the same path.
Clear gutters and downspouts
Scoop leaves out of gutters if you can reach them safely, then run a hose into each downspout to make sure it flows. Point downspouts away from the foundation onto splash blocks or into a drain built for rainwater.
Clean area, patio and driveway drains
Lift each grate, scoop out leaves, dirt and debris, and rinse the basin. Run a hose into it and watch the outlet — at the curb or a pop-up emitter in the yard. If it backs up, a hand snake can clear short runs.
Check the low spots
Walk the property and find where water collects — driveway bottoms, patios against the house, side yards. Make sure their drains are clear and the ground slopes away from the walls.
Check your sewer cleanout cap
Find your cleanout (how) and make sure the cap is on, intact and not sitting in a low spot that floods. A missing or broken cap lets rainwater and dirt into your sewer line.
Keep rainwater out of the sewer
Never route downspouts, yard drains or a sump pump into a sewer cleanout or sewer drain. Rainwater belongs in the yard or the street gutter; putting it in the sewer can overload the line and back up into homes — and is generally prohibited.
Know what to do if it backs up
Read what to do in a main sewer line backup now, so you're not searching while it's happening.
Backwater valves: do you need one?
A backwater valve lets sewage flow out of your house but closes if the public sewer backs up toward you.
Homes with low fixtures
Homes where a floor drain or fixture sits low relative to the public sewer — a basement, a lower level, or a house below the street — are the most at risk of backups from the public line.
Ask your city
Requirements for backwater valves are set by local building codes. In the City of LA, check with LADBS; elsewhere, your city's building department. We'll tell you what applies when we look at your line.
They need checking
A backwater valve has a flap that must move freely. Check it periodically — especially before the rainy season. See backwater valves.
Signs rain is getting into your sewer
Drains that slow down or gurgle during heavy rain, sewer smell after rain, or a cleanout that fills with water when it rains can mean groundwater or rainwater is getting into a cracked line. That's a camera inspection — ideally before the next big rain. Report flooded streets to your city; in the City of LA, that's LA Sanitation via 311.
When to call a pro.
Call if:
An area drain backs up into the yard
A buried drain line that won't clear with a hose or hand snake may be crushed, root-filled or disconnected. We'll find out with a camera.
Backups every time it rains
That's a sign of a problem in your lateral or a backwater issue. Get it inspected before the next big rain.
Water against the foundation
Persistent water at the walls can mean drainage that needs reworking. We'll look at where it's going and why.
Rooter Pros is open 24/7 — flat-rate pricing agreed before work starts.
Call (818) 669-9019Rainy season FAQ
Straight answers, no sales pitch.
Can I connect my downspouts to the sewer?
No. Rainwater should soak into the yard or run to the street gutter, not into the sewer. Connections to the sewer can overload the line and are generally prohibited.
Why does my sewer back up when it rains?
Rainwater can enter sewer lines through cracks, open or broken cleanouts and improper connections, overloading pipes. A camera inspection finds where it's getting in.
Do I need a backwater valve?
It depends on how your fixtures sit relative to the public sewer and on local code. Ask your city's building department, or we can assess it when we inspect your line.
Who do I call about a flooded street?
Your city's public works or sanitation department. In the City of Los Angeles, call 311.
Drains not ready for rain?
If this doesn't work or you'd rather not mess with it, call (818) 669-9019. 24/7 emergency service · Free estimates · Upfront flat-rate pricing