What Does It Mean When Black Water Is Coming Up From The Tub Drain?

Black water coming up your bathtub's drain and spilling into your tub isn't exactly a comforting sight. Adding insult to this aesthetic injury is knowing that the discolored water could be waste that's backing up from the sewer.

For the sake of your health, discontinue using the bathtub until the problem is resolved. A quick call to your local water and sewer authority may confirm a sewer backup in your area as the cause, which means you must wait for the city to correct the problem.

The different plumbing fixtures in your house have their own drainpipes, but those drainpipes converge into larger pipes. Several plumbing fixtures' drainpipes feed into the larger pipes, called branch pipes, which eventually connect to the sewer drainpipe that feeds into the sewer system or septic tank. A clog in one of the branch pipes or the sewer pipe will allow waste water from one plumbing fixture to come up the drain of another.

To clear a clog that sits in a branch pipe, remove the toilet that sits nearest the bathtub from its mount on the floor. Feeding the flexible line of a toilet auger, also called a plumbing snake, down the toilet's drainpipe gives you the greatest chance of reaching and removing the clog in the branch pipe since you do not need to feed the line through the plumbing fixture itself.

You may also check the cleanouts between your house and the sewer lines or septic tank. Removing the cleanout covers allows you to see if the water inside the sewer pipe is sitting stagnant, indicating there's a large clog that should be cleared by a plumber.

All of the drainpipes in your house's plumbing system need to be ventilated to work correctly and safely. Each branch pipe connects to a vent pipe, which runs up through the house's roof.

The vent pipes transport sewer gases up and out of the house's plumbing. The vent pipes also allow fresh air to enter the plumbing, replacing air lost with waste water transported to the sewer or septic tank. An obstruction in a vent pipe can lead to sewage water backing up a drainpipe.

If you suspect one of the vent pipes in your house's plumbing has a clog, you must look for and remove clogs from the house's rooftop. Climbing onto the roof can pose a serious safety hazard, particularly during inclement weather, so wait for better weather or contact a plumber to do this work for you.

Sometimes you may see an obstruction on top of the vent pipe, or near the opening, which you can remove easily. Other times you must shine a flashlight down the vent pipes to locate obstructions. A drain auger or a garden hose with a high-pressure nozzle allows you to knock free clogs that sit deep down a vent pipe.