A clogged sewer drain may be a plumbing emergency and health risk. Without the main sewer line or septic field, wastewater may back up into fixtures or floor drains. When a sewer line drain is clogged, none of the home’s plumbing should be used.
Drainage Basics
Homes with city sewer service have a single underground sewer drain pipe to the street. The drain pipe diameter is 4 inches but can be 3 inches. This main sewer drain pipe under the yard connects to the main drain inside the house, which accepts wastewater from sinks, tubs, showers, toilets, and the washing machine. These 1 1/4 to 2 1/2-inch-diameter branch drains are smaller. If the main sewer drain is clogged, it can back up all the drains in the house. A clogged main sewer drain pipe may cause wastewater and raw sewage to back up into a home’s basement or floor.
Main Drain Clog Symptoms
Here are some clogged drain signs.
Clogged Plumbing
Multiple plumbing fixtures backing up at once indicate a sewer drain clog. Toilets are often the first to experience problems, but any low-lying fixture, such as a shower or bathtub on the main level, can be involved. If you suspect a clogged sewer drain, check the toilet first.
Fixture Reactions
Check the following fixtures for odd sounds or behavior, starting with the basement. Because backups start at the clog and move up, the lowest drains and fixtures usually back up first.
- Toilets have the quickest path to the main drain and the largest drain pipes, thus problems commonly start there. A toilet, sink, tub, or washing machine drain may gurgle. This shows the drain problem.
- Mainline stoppage affects tub and shower drain. Sink drains are lower. Unclog tub and shower drain. Showers and tubs may fill with sewage during a backup.
- Run the sink to check for trapped air. If you run a sink near the toilet, the water level may rise.
- The washer can indicate a clogged sewage drain. The sewer drain is clogged if washing machine water overflows the toilet or fills the tub or shower.
Main House Trap, Drain Clean Out Fitting
The main house trap is the drain cleanout fitting. It has street and house clean-outs. Brass or fit all plugs are used. Brass plugs unscrew counterclockwise, but if they haven’t been removed in a while, they won’t. They must be cut off.
Fit all must be removed by hammering side-to-side. Replace worn-out brass plugs.
House Trap Workflow
First, remove the street plug. If the plug is under pressure, slam it and call a pro. The stoppage is likely outside the foundation. Professionals should snake your sewer with a high-powered machine to fix this blockage.
Cleaning—Carefully
A drain clean-out can be located at the bottom of the vertical soil stack or on the floor where the horizontal main drain pipe runs to the sewer main. Using pliers or a pipe wrench to grip the nut allows you to unscrew and remove the plug. Most homes have a main drain or sewer line clean-out.
Clogged Main Sewer Drain
No water or toilet flushing! If the clog is in your line, adding water won’t make it worse (see below). As a precaution, turn off the house’s main water supply. Call a plumber or drain specialist to clear the drain. These professionals use motorized augers to quickly clear main sewer drain clogs.
