Why Does My Sewer Back Up After Heavy Rain?

Frisco runs two separate pipe systems. Storm drains carry rainwater off streets and toward creeks and lakes. Sanitary sewers carry waste from your home to a treatment plant.

Some older cities combine the two into one pipe. That's why so much online advice blames the city system whenever it rains. Here, the sewer line from your house was never meant to carry rainwater at all.

So if your sewer backs up only when it storms, rainwater is finding a way in. Engineers call this inflow and infiltration. Inflow is rain pouring in through an opening. Infiltration is groundwater seeping in through cracks and loose joints.

Homes here sit on slabs, so there's no basement drain to catch it. Instead, the water shows up at the lowest drains, like a downstairs shower, tub, or toilet. Sometimes it spills out of the yard cleanout first.

The fastest way to find the problem is to follow the water. Start at the roof and work toward the street.

Every storm sends a lot of water off your roof. Gutters and downspouts should carry it to your lawn or the storm drain, away from the sewer.

Some setups tie a downspout or a yard drain straight into the sewer line. It might be an older connection or a do-it-yourself fix. Either way, the rain off your roof goes straight into a pipe built for household waste.

Walk around the house and see where each downspout ends. Many empty onto the ground or into a buried pipe that runs toward the street.

A buried pipe isn't a problem on its own, but it's worth knowing where it goes. If you can't tell whether it reaches the storm drain or your sewer, have it traced.

Your cleanout is the short, capped pipe sticking up from the ground, usually near the house. It gives a plumber a way into your sewer line.

That cap is all that keeps rainwater out of the opening. If it's missing, loose, or cracked, rain and yard debris pour straight into your sewer. A lawn mower clipping the cap is a common way it gets broken.

Check your cleanout cap

• Is it there? A missing cap leaves the sewer wide open to rain.
• Is it tight? A loose cap lets water seep in around the edges.
• Is it whole? A cracked cap or pipe lets water in even when the cap is on.

Replacing a missing or broken cap is often the simplest fix in this whole article. For a homeowner's checklist, see this Texas city's guide to keeping rainwater out of sewers.

If the roof and yard check out, the problem may be underground. After heavy rain, the ground fills with water and the water level in the soil rises.

Your sewer line sits in that wet soil. Any crack, hole, or loose joint lets that groundwater seep in. On a dry day the line works fine, but a long rain adds water it was never meant to carry.

Roots make it worse. They find those same cracks and joints, and they grow inside toward the water. If you've had roots in your sewer line before, they may be part of the story.

A partial clog or a sag in the line causes trouble too. The pipe handles normal use, but a surge of rainwater fills what little room is left. That's when sewage backs up into the house.

None of this shows from the yard. A camera inspection is the only way to see cracks, roots, or a sag inside the pipe.

Sometimes the problem isn't on your property at all. During a big storm, the city's sewer main can fill with rainwater that got in somewhere else along the system.

When the main is full, the flow can reverse. Sewage looks for the lowest opening it can find, and that can be a drain inside your home.

A few clues point to the main:

• Neighbors on your street are backing up too
• It only happens in the heaviest storms

If it looks like the main, report it to the city's Public Works Department at 972-292-5800. The city can look into problems with its own lines.

A backwater valve can protect your home when the main overloads. We cover how it works in the prevention section below.

If sewage is coming up into your home right now, start here. These steps limit the damage and help keep your household safe until a plumber arrives.

During a sewer backup

• Stop using water. Don't flush, shower, or run the dishwasher or washing machine. Every gallon adds to the backup.
• Stay out of the water. Sewage carries harmful bacteria and viruses.
• Keep kids and pets away. Wash anything that touches the water, including hands and shoes.
• Stay clear of electrical outlets and cords near standing water.
• Take photos before you clean up. Your insurance company may ask for them.
• Call a plumber to clear the line and find out why it backed up.

Clearing the backup is only half the job. If rain caused it, the water will keep getting in until the entry point is fixed. We can get a backup cleared and then track down where the water came from.

A sewer that backs up every time it rains has a way in, and we can find it. We clear the backup, trace where the water is coming from, and fix the entry point.

We answer calls 24/7. Before you call, read reviews from Frisco homeowners about working with Berkeys in Frisco.

Berkeys Plumbing, A/C & Electrical

Business Address: 4645 Avon Ln Suite 260, Frisco, TX 75033

Call (214) 216-1727 for sewer backup repair in Frisco.