The sudden sight of a sewer back up can turn a lazy Sunday morning into a stressful scramble for help. Not only is this an unpleasant task to handle, can also do significant damage to your floors, walls, electrical system, furniture and other belongings.

Learn what causes a sewer backup and what you should do if you're faced with one.

Your home's outgoing sewer lines move wastewater from your toilet, sinks, tub and washing machine away from your home. All household drains converge below the building in a main sewer line that carries wastewater to the municipal sewer lines, usually located in the street.

If an individual drain is clogged, you can sometimes fix it yourself with a plunger or a snake. But if you notice issues in multiple drains, such as slow-flowing water, gurgling noises and water backing up into your home, you probably have a main sewer line problem.

The Insurance Information Institute (III) states that many homeowners don't realize they are responsible for the maintenance and repair of the sewer pipeline between their home and the city sanitary sewer main. Some of the most common threats to keeping your main sewer line in good working order include the following:

• Tree roots: The sewer lines beneath your property can be an attractive water source for the trees and shrubs in your yard. If the roots find cracks in the pipes, they can grow very large and cause extensive blockages or damage. This is especially common in older homes. Have a professional cut the roots for you regularly.
• Grease, oils and fats: Pouring greasy substances down your kitchen drain can create blockages in your drain line as they cool and solidify. Dispose of cooking oils properly using a heat-resistant container.
• Certain paper products: Putting paper towels, disposable diapers and feminine hygiene products down the toilet can be an invitation to drain disaster. Because they don't deteriorate quickly, these products can often cause major clogging.
• Older sewer lines: If your home's sewer pipes are made from cast iron or clay, their age predisposes them to break. It is recommended to replace them with new plastic pipes, which will also help prevent tree roots from invading.
• Problems with the municipal sewer: Sometimes city lines can fail from events such as floods, causing water to back up into your home. Consider hiring a qualified plumber to install a backwater prevention valve.
• A poorly or illegally designed home-drainage system: Connecting flood-control systems, such as French drains and sump pumps, to your main sanitary sewer line is illegal. The accumulated debris can clog and cause backups.

Treat a severe sewer backup that sends waste flowing into your home through drains as an emergency. Prompt cleanup of your affected property can help minimize the damage and prevent mold contamination. Take the following steps:

• Call a licensed plumber immediately, and do not use sinks, toilets or showers while you wait.
• Keep children and pets away from the affected area.
• Once the pipes have been repaired, the water should recede. Depending on the severity of the damage, you might want to hire a professional sewage cleanup service. If you decide to tackle the job yourself, be sure to put on protective gear. You'll need safety goggles, a facemask, heavy-duty rubber gloves and boots when dealing with the contaminated areas.
• Use a shop vacuum on the wet-dry setting to remove the waste. Mop the floors and wipe the walls with disinfectant.
• When dealing with absorbent materials, such as wet carpets, upholstery and drapes, you'll need to decide if a steam-cleaning is sufficient for disinfecting or if the materials should be discarded.
• Depending on how much standing water you had in your home, you might need to remove damaged wallboard or wall covering.

To help ensure you have the appropriate level of homeowners insurance talk with your insurance agent to determine if you have coverage for losses associated with water sewer backup.