How to Prepare Your Plumbing for California's Rainy Season

California's rainy season — typically November through March — puts extra stress on your home's drainage systems, sewer lines, and water management infrastructure. Heavy rain saturates soil, raises groundwater levels, and sends large volumes of water into storm drains and sewer systems. For homeowners, this means an increased risk of sewer backups, drainage failures, and water intrusion if your systems are not prepared.

Clear Outdoor Drains and Gutters

Leaves, debris, and sediment that accumulate in gutters, downspouts, yard drains, and area drains during the dry months can cause water to pool against your foundation during heavy rain. Clear all exterior drains before the first significant rain. Make sure downspouts direct water at least four feet away from the foundation and that yard drains flow freely.

Test Your Sump Pump

If your home has a sump pump — common in lower-lying San Carlos neighborhoods and homes with below-grade areas — test it before the rainy season begins. Pour a bucket of water into the sump pit and verify that the pump activates, runs smoothly, and discharges water through the outlet pipe. Listen for unusual noises and check that the discharge pipe is clear and directed away from the foundation.

If the pump does not activate, runs continuously, or makes grinding sounds, have it serviced or replaced before the rain arrives. A failed sump pump during a heavy storm can result in significant basement or crawl space flooding.

Inspect Your Sewer Lateral

During heavy rain, municipal sewer systems can become overwhelmed, and homes with compromised sewer laterals are at higher risk of backups. If your sewer lateral has existing cracks, root intrusion, or partial blockages, heavy rain increases the likelihood of a backup into your home.

Scheduling a sewer camera inspection and preventive cleaning before the rainy season addresses vulnerabilities when the work can be done on your timeline rather than as an emergency during a storm.

Check for Exterior Leaks

Walk the perimeter of your home and inspect exterior hose bibs, outdoor faucet connections, and any exposed pipes. Repair dripping faucets and replace cracked or worn hose bibs. Even small drips waste water and can cause localized erosion near your foundation during the rainy season when soil is already saturated.

Know Your Emergency Plan

Make sure everyone in your household knows where the main water shutoff valve is and how to operate it. Keep an emergency plumber's number accessible. If water begins backing up from drains during a storm, avoid using water until the backup clears or professional help arrives — running additional water into a backed-up system makes the situation worse.