Clogged Cast Iron Floor Drain

Floor drains can become clogged.

Floor drains, which carry away waste water from flooding, washing machines, dishwashers, water heaters and other moisture buildup, can become clogged with lint, dirt, soap scum, bacteria or other blockages over time. Regardless of whether your floor drain is constructed of iron or another material, unclogging a floor drain requires a power auger and some patience.

Iron Drains

Although all floor drains clog, a specific issue with cast iron drains is accumulated rust. San Diego home inspector Steve John estimates that cast iron drains and drain lines have a life span between 50 and 70 years. If you attempt to clear a clog from your cast iron floor drain and cannot break through using an auger, you may have a rust buildup inside your pipes causing the drain’s slow-down or back-up. In this case, you may need to have the drain and drain lines replaced to avoid cracking and leaking.

Beginning

Remove the strainer that covers the floor drain. You may want to use protective gloves when removing the drain to protect your hands from the sticky or gloopy material that collects around the floor drain. Next, look for the clean-out plug. This plug is usually on one side of the drain basin. Use a wrench to remove the plug. This allows you access into the drain to clear out any clogs and blockages. If your drain does not have a clean-out plug, you will need to try and feed an auger through the drain; this may require you to contact a licensed plumber for assistance.

Using an Auger

Augers, also called snakes, are handy to unclog most types of clogs in your home’s plumbing. For a clogged floor drain, however, you should rent an electric power auger with at least 50 feet of cable. You can rent power augers at most home improvement, plumbing supply or hardware stores. Plug in the auger and position the body near the drain. Feed a few feet of cable down the drain using either the hand crank or the foot pedal, depending on the model of auger. Set the switch or button that feeds the cable clockwise, then turn on the auger. Push the cable down further into the drain pipes until you feel resistance. This resistance is probably the source of the clog.

Clear the Clog

When you reach the clog, turn off the auger’s motor and switch the motor from clockwise to counter-clockwise and back out a few feet of cable. Reverse again to feed the cable into the clog and then back out again. Repeat this reverse process until you feel less resistance. When there is no or little resistance, set the motor counter-clockwise and slowly retract the cable. You may want to have a waste bucket nearby to place any detritus that is stuck to the end of the cable from the clog; it sometimes can be quite messy.

Finishing

Pour several buckets of hot water down the drain to rinse the pipes before replacing the plugs and the drain. If the water drains slowly or backs up, reinsert the auger and feed more cable into the drain, as there may be a deeper clog. When done, be sure the plugs and drains are seated well or else sewer gas may escape into your home through the gaps.

References

• This Old House; Clear Any Clogged Drain; Merle Henkenius
• ACE Hardware: Unstopping Clogged Drains, Toilets, and Sewers
• All Pro Home Inspections: Cast Iron Drain Lines