Wet El Niño Winter? Get Your Main Line Ready

Sewer cleanout installed in a yard, the access point a plumber uses to clear a main line

A very strong El Niño is underway, according to NOAA's Climate Prediction Center. The center's October 15, 2026 seasonal outlook shows an elevated likelihood of above-normal precipitation for much of California from November through January (NOAA CPC outlook). No forecast is certain, but a wetter-than-usual winter is a good reason to check your drains and sewer line now, before the heavy rain arrives.

Why main lines back up in wet weather

Your main line carries every drop of wastewater from your home to the city sewer. A line that's partly blocked by grease, wipes, buildup or tree roots, or that has a crack or a sag, can get by for months. Then a busy holiday weekend or a stretch of wet weather adds stress. Groundwater can seep into cracked or offset pipe and older clay joints, and a slow drain turns into a backup in your lowest tub, shower or floor drain. Our post on why a main line keeps backing up covers the usual causes in older Burbank, Glendale and Valley homes.

Warning signs to watch for

Several drains running slow at once. One slow sink is usually a local clog. Several slow drains often point to the main line.
Toilets that gurgle when another fixture drains. See what gurgling drains mean.
Water coming up in a shower, tub or floor drain.
Sewer smell inside the house or outside near the line. See sewer smell in the house.
A soggy or unusually green strip of yard over the sewer line.

If sewage is already coming up, stop using water and see what to do when the main line backs up.

Four steps to take now

Clear slow drains early. A drain cleaning through the cleanout clears grease, buildup and roots before they cause a backup in the middle of a downpour.
Schedule a sewer camera inspection. A small camera goes into the line and shows roots, buildup, cracks, breaks and sags. You see the footage, so you know what's going on before you decide on any repair. Read the signs you need a sewer camera inspection and what a sewer camera shows.
Ask about a backwater valve. A backwater valve helps keep sewage from flowing back into your home if the line backs up.
Find your cleanout. Knowing where it is means a plumber can reach a main-line clog from outside. Here's how to find your sewer cleanout, and if you don't have one, cleanout installation makes future work faster.

For the outdoor side of rain prep, such as gutters, downspouts and yard drains, see our LA rainy season prep checklist.

Don't forget the water heater

Cold mornings put the most demand on your water heater. If yours is leaking, making noise or not keeping up, have it looked at before winter. Here are the signs a water heater is dying. If you're replacing a gas water heater this year, check the SoCalGas water heater rebate before December 31.

What it costs at Rooter Pros

Drain cleaning and sewer camera inspections come with a free estimate: call (818) 669-9019 and you get the price before any work begins. New customers can also ask about our $49 first-time drain cleaning coupon: new customers only, one per household, one drain or line per visit, residential only, Monday–Friday 7am–5pm, accessible ground-level cleanout required, not valid with other offers. It's a new-customer special, not our regular rate. See our pricing page, the drain cleaning cost guide and the sewer camera inspection cost guide for more.

Want your main line checked before the rain? Rooter Pros handles drain cleaning, sewer camera inspections, sewer line repair and water heaters across the San Fernando Valley, Glendale, Pasadena, Santa Clarita and Los Angeles. Licensed & bonded (CSLB #917630), open 24/7 including holidays, with no overtime charges.

Call (818) 669-9019

Source: NOAA Climate Prediction Center, Prognostic Discussion for Long-Lead Seasonal Outlooks, issued October 15, 2026 (cpc.ncep.noaa.gov). Seasonal outlooks are probabilities, not promises of rainfall. Rooter Pros prices are starting prices for straightforward residential jobs with normal access.

Rainy season main line FAQ

Straight answers, no sales pitch.

Does rain really cause sewer backups?

Rain doesn't clog a healthy line by itself, but it can push a struggling one over the edge. Groundwater and rainwater can get into cracked or offset sewer pipes and older clay joints, and that extra water takes up room in a line that's already partly blocked by roots, grease or wipes. The result is often a backup into the lowest drain in the house during or just after heavy rain.

What does NOAA expect for this winter?

NOAA's Climate Prediction Center outlook issued October 15, 2026 says a very strong El Niño is underway and shows an elevated likelihood of above-normal precipitation for much of California for November through January. It's a probability, not a promise, but it's a good reason to check your drains and sewer line before the rain.

When should I get a sewer camera inspection?

Get one if more than one drain is slow, toilets gurgle when other fixtures drain, the main line has backed up before, you have big trees near the sewer line, or the house has original clay or cast iron pipe. A camera shows roots, buildup, cracks and sags so you know what's going on before you decide on any repair. At Rooter Pros, call us for a free estimate on a camera inspection.

What is a backwater valve?

A backwater valve is a one-way valve on the sewer line. It lets wastewater leave the house but closes if sewage tries to flow back in, which helps protect the lowest drains in the home during a backup. Whether you need one depends on how your home sits relative to the street sewer; a plumber can check.

How much does main line drain cleaning cost at Rooter Pros?

Rooter Pros gives free estimates on drain cleaning and sewer camera inspections, and you get the price before any work begins. New customers can ask about our $49 first-time drain cleaning coupon (terms apply).

Wet winter ahead? Get your drains and main line ready before the rain.

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